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دانلود کتاب Guyton and Hall textbook of medical physiology
دانلود کتاب کتاب درسی فیزیولوژی پزشکی گایتون و هال
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Guyton and Hall textbook of medical physiology
ویرایش: [14 ed.] نویسندگان: John Edward Hall, Michael Edward Hall سری: ISBN (شابک) : 9780323597128, 0323672809 ناشر: Elsevier Inc. سال نشر: 2021 تعداد صفحات: [1028] زبان: English فرمت فایل : PDF (درصورت درخواست کاربر به PDF، EPUB یا AZW3 تبدیل می شود) حجم فایل: 61 Mb
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توجه داشته باشید کتاب کتاب درسی فیزیولوژی پزشکی گایتون و هال نسخه زبان اصلی می باشد و کتاب ترجمه شده به فارسی نمی باشد. وبسایت اینترنشنال لایبرری ارائه دهنده کتاب های زبان اصلی می باشد و هیچ گونه کتاب ترجمه شده یا نوشته شده به فارسی را ارائه نمی دهد.
توضیحاتی در مورد کتاب کتاب درسی فیزیولوژی پزشکی گایتون و هال
کتاب درسی فیزیولوژی پزشکی گایتون و هال، ویرایش چهاردهم، به دلیل سبک ارائه واضح، صدای تک نویسنده و تمرکز بر محتوایی که بیشتر مربوط به دانشجویان بالینی و پیش بالینی است، از قالبی متمایز برای اطمینان از حداکثر یادگیری و حفظ مفاهیم پیچیده استفاده می کند. . اندازه فونت بزرگتر بر اطلاعات اصلی تأکید دارد، در حالی که اطلاعات پشتیبانی، از جمله نمونه‌های بالینی، با فونت کوچک‌تر و با رنگ آبی کم‌رنگ برجسته می‌شوند - مرور سریع متن ضروری یا دنبال کردن مطالعه عمیق‌تر را آسان می‌کند. این رویکرد دو رنگ، همراه با سایر ویژگی های برجسته، این متن پرفروش را مورد علاقه دانش آموزان در سراسر جهان قرار می دهد. یک چشم انداز بالینی را ارائه می دهد که با دانش آموز بالینی و پیش بالینی نوشته شده است و فیزیولوژی پایه را با پاتوفیزیولوژی پیوند می دهد. تمرکز بر مواد اصلی و نحوه حفظ هموستاز بدن برای سالم ماندن، با تاکید بر اصول مهمی که در تصمیم گیری بالینی بعدی کمک می کند. اطلاعات را در فصل های کوتاه با استفاده از صدایی مختصر و خوانا ارائه می کند که یادگیری و حفظ را تسهیل می کند. شامل بیش از 1200 طرح و نمودار تمام رنگی - همه با دقت ساخته شده اند تا درک فیزیولوژی را آسان تر کنند. دارای پوشش بالینی گسترده از جمله چاقی، اختلالات متابولیک و قلبی عروقی، بیماری آلزایمر، و سایر بیماری های دژنراتیو. شامل دسترسی آنلاین به چهره‌های تعاملی، صدای جدید صدای قلب، انیمیشن‌ها، سوالات خودارزیابی و موارد دیگر است. نسخه کتاب الکترونیکی پیشرفته همراه با خرید. کتاب الکترونیکی پیشرفته شما به شما امکان می دهد به تمام متن ها، شکل ها و مراجع کتاب در دستگاه های مختلف دسترسی داشته باشید.
توضیحاتی درمورد کتاب به خارجی
Known for its clear presentation style, single-author voice, and focus on content most relevant to clinical and pre-clinical students, Guyton and Hall Textbook of Medical Physiology, 14th Edition, employs a distinctive format to ensure maximum learning and retention of complex concepts. A larger font size emphasizes core information, while supporting information, including clinical examples, are detailed in smaller font and highlighted in pale blue - making it easy to quickly skim the essential text or pursue more in-depth study. This two-tone approach, along with other outstanding features, makes this bestselling text a favorite of students worldwide. Offers a clinically oriented perspective written with the clinical and preclinical student in mind, bridging basic physiology with pathophysiology. Focuses on core material and how the body maintains homeostasis to remain healthy, emphasizing the important principles that will aid in later clinical decision making. Presents information in short chapters using a concise, readable voice that facilitates learning and retention. Contains more than 1,200 full-color drawings and diagrams - all carefully crafted to make physiology easier to understand. Features expanded clinical coverage including obesity, metabolic and cardiovascular disorders, Alzheimer's disease, and other degenerative diseases. Includes online access to interactive figures, new audio of heart sounds, animations, self-assessment questions, and more. Enhanced eBook version included with purchase. Your enhanced eBook allows you to access all of the text, figures, and references from the book on a variety of devices.
فهرست مطالب
NOTE TO INSTRUCTORS Guyton and Hall Textbook of Medical Physiology Copyright Dedication Preface 1 - Functional Organization of the Human Body and Control of the “Internal Environment” 2 - The Cell and Its Functions 3 - Genetic Control of Protein Synthesis, Cell Function, and Cell Reproduction 4 - Transport of Substances Through Cell Membranes 5 - Membrane Potentials and Action Potentials Basic Physics of Membrane Potentials Membrane Potentials Caused by Ion Concentration Differences Across a Selectively Permeable Membrane The Nernst Equation Describes the Relationship of Diffusion Potential to the Ion Concentration Difference Across a Membrane. The... The Goldman Equation Is Used to Calculate the Diffusion Potential When the Membrane Is Permeable to Several Different Ions. When... Measuring the Membrane Potential Resting Membrane Potential of Neurons Active Transport of Sodium and Potassium Ions Through the Membrane—the Sodium-Potassium (Na+-K+) Pump. Recall from Chapter 4 t... Origin of the Normal Resting Membrane Potential Contribution of the Potassium Diffusion Potential. In Figure 5-5A, we assume that the only movement of ions through the membran... Contribution of Sodium Diffusion Through the Nerve Membrane. Figure 5-5B shows the addition of slight permeability of the nerve... Contribution of the Na+-K+ Pump. In Figure 5-5C, the Na+-K+ pump is shown to provide an additional contribution to the restin... Neuron Action Potential Resting Stage. The resting stage is the resting membrane potential before the action potential begins. The membrane is said to b... Depolarization Stage. At this time, the membrane suddenly becomes permeable to sodium ions, allowing rapid diffusion of positive... Repolarization Stage. Within a few 10,000ths of a second after the membrane becomes highly permeable to sodium ions, the sodium ... Activation and Inactivation of the Voltage-Gated Sodium Channel Activation of the Sodium Channel. When the membrane potential becomes less negative than during the resting state, rising from −... Inactivation of the Sodium Channel. The upper right panel of Figure 5-7 shows a third state of the sodium channel. The same inc... Voltage-Gated Potassium Channel and Its Activation Initiation of the Action Potential A Positive-Feedback Cycle Opens the Sodium Channels. As long as the membrane of the nerve fiber remains undisturbed, no action ... Initiation of the Action Potential Occurs Only After the Threshold Potential is Reached. An action potential will not occur unti... Propagation of the Action Potential Direction of Propagation. As demonstrated in Figure 5-11, an excitable membrane has no single direction of propagation, but the... Plateau in Some Action Potentials Rhythmicity of Some Excitable Tissues—Repetitive Discharge Special Characteristics of Signal Transmission in Nerve Trunks Myelinated and Unmyelinated Nerve Fibers. Figure 5-15 shows a cross section of a typical small nerve, revealing many large nerv... Saltatory Conduction in Myelinated Fibers from Node to Node. Even though almost no ions can flow through the thick myelin sheath... Velocity of Conduction in Nerve Fibers. The velocity of action potential conduction in nerve fibers varies from as little as 0.2... Excitation—The Process of Eliciting the Action Potential Threshold for Excitation and Acute Local Potentials. A weak negative electrical stimulus may not be able to excite a fiber. Howe... Inhibition of Excitability—Stabilizers and Local Anesthetics In contrast to the factors that increase nerve excitability, membrane-stabilizing factors can decrease excitability. For exampl... 6 - Contraction of Skeletal Muscle 7 - Excitation of Skeletal Muscle: Neuromuscular Transmission and Excitation-Contraction Coupling Neuromuscular Junction and Transmission of Impulses from Nerve Endings to Skeletal Muscle Fibers Acetylcholine Opens Ion Channels on Postsynaptic Membranes. Figure 7-2 also shows many small acetylcholine receptors and voltage... Destruction of the Released Acetylcholine by Acetylcholinesterase. The acetylcholine, once released into the synaptic space, con... End Plate Potential and Excitation of the Skeletal Muscle Fiber. The sudden insurgence of sodium ions into the muscle fiber when... Safety Factor for Transmission at the Neuromuscular Junction—Fatigue of the Junction. Ordinarily, each impulse that arrives at t... Muscle Action Potential Excitation-Contraction Coupling Transverse Tubule–Sarcoplasmic Reticulum System Release of Calcium Ions by the Sarcoplasmic Reticulum Calcium Pump Removes Calcium Ions from the Myofibrillar Fluid After Contraction Occurs. Once the calcium ions have been release... Excitatory Pulse of Calcium Ions. The normal resting state concentration (<10−7 molar) of calcium ions in the cytosol that bathe... 8 - Excitation and Contraction of Smooth Muscle Contraction of Smooth Muscle Types of Smooth Muscle Multi-Unit Smooth Muscle. Multi-unit smooth muscle is composed of discrete, separate, smooth muscle fibers. Each fiber operate... Unitary Smooth Muscle. Unitary smooth muscle is also called syncytial smooth muscle or visceral smooth muscle. The term unitary ... Contractile Mechanism in Smooth Muscle Chemical Basis for Smooth Muscle Contraction Physical Basis for Smooth Muscle Contraction Comparison of Smooth Muscle Contraction and Skeletal Muscle Contraction Slow Cycling of the Myosin Cross-Bridges. The rapidity of cycling of the myosin cross-bridges in smooth muscle—that is, their ... Low Energy Requirement to Sustain Smooth Muscle Contraction. Only 1/10 to 1/300 as much energy is required to sustain the same t... Slowness of Onset of Contraction and Relaxation of the Total Smooth Muscle Tissue. A typical smooth muscle tissue begins to cont... Maximum Force of Contraction Is Often Greater in Smooth Muscle Than in Skeletal Muscle. Despite the relatively few myosin filame... Latch Mechanism Facilitates Prolonged Holding of Contractions of Smooth Muscle. Once smooth muscle has developed full contractio... Stress-Relaxation of Smooth Muscle. Another important characteristic of smooth muscle, especially the visceral unitary type of ... Regulation of Contraction by Calcium Ions Calcium Ions Combine with Calmodulin to Cause Activation of Myosin Kinase and Phosphorylation of the Myosin Head. In place of tr... Source of Calcium Ions That Cause Contraction Role of the Smooth Muscle Sarcoplasmic Reticulum. Figure 8-4 shows a few slightly developed sarcoplasmic tubules that lie near t... Smooth Muscle Contraction Is Dependent on Extracellular Calcium Ion Concentration. Whereas changing the extracellular fluid calc... A Calcium Pump Is Required to Cause Smooth Muscle Relaxation. To cause relaxation of smooth muscle after it has contracted, the ... Myosin Phosphatase Is Important in Cessation of Contraction. Relaxation of the smooth muscle occurs when the calcium channels cl... Possible Mechanism for Regulating the Latch Phenomenon. Because of the importance of the latch phenomenon in smooth muscle, and ... Nervous and Hormonal Control of Smooth Muscle Contraction Neuromuscular Junctions of Smooth Muscle Physiologic Anatomy of Smooth Muscle Neuromuscular Junctions. Neuromuscular junctions of the highly structured type found on ske... Membrane Potentials and Action Potentials in Smooth Muscle Membrane Potentials in Smooth Muscle. The quantitative voltage of the membrane potential of smooth muscle depends on the momenta... Action Potentials in Unitary Smooth Muscle. Action potentials occur in unitary smooth muscle (e.g., visceral muscle) in the same... Spike Potentials. Typical spike action potentials, such as those seen in skeletal muscle, occur in most types of unitary smooth ... Action Potentials with Plateaus. Figure 8-7C shows a smooth muscle action potential with a plateau. The onset of this action pot... Calcium Channels Are Important in Generating the Smooth Muscle Action Potential. The smooth muscle cell membrane has far more vo... Slow Wave Potentials in Unitary Smooth Muscle Can Lead to Spontaneous Generation of Action Potentials. Some smooth muscle is sel... Excitation of Visceral Smooth Muscle by Muscle Stretch. When visceral (unitary) smooth muscle is stretched sufficiently, spontan... Local Tissue Factors and Hormones Can Cause Smooth Muscle Contraction Without Action Potentials Smooth Muscle Contraction in Response to Local Tissue Chemical Factors. In Chapter 17, we discuss control of contraction of the ... Effects of Hormones on Smooth Muscle Contraction. Many circulating hormones in the blood affect smooth muscle contraction to som... Mechanisms of Smooth Muscle Excitation or Inhibition by Hormones or Local Tissue Factors. Some hormone receptors in the smooth m... 9 - Cardiac Muscle; The Heart as a Pump and Function of the Heart Valves Physiology of Cardiac Muscle Cardiac Muscle Anatomy Cardiac Cycle Diastole and Systole Relationship of the Electrocardiogram to the Cardiac Cycle The Atria Function as Primer Pumps for the Ventricles Function of The Ventricles as Pumps The Ventricles Fill with Blood During Diastole. During ventricular systole, large amounts of blood accumulate in the right and l... Period of Ejection. When the left ventricular pressure rises slightly above 80 mm Hg (and the right ventricular pressure rises s... Period of Isovolumic (Isometric) Relaxation. At the end of systole, ventricular relaxation begins suddenly, allowing both the ri... End-Diastolic Volume, End-Systolic Volume, and Stroke Volume Output. During diastole, normal filling of the ventricles increas... The Heart Valves Prevent Backflow of Blood During Systole Atrioventricular Valves. The A-V valves (i.e., the tricuspid and mitral valves) prevent backflow of blood from the ventricles t... Aortic Pressure Curve Volume-Pressure Diagram During the Cardiac Cycle; Cardiac Work Output. The red lines in Figure 9-10 form a loop called the vol... Concepts of Preload and Afterload. In assessing the contractile properties of muscle, it is important to specify the degree of t... Regulation of Heart Pumping What Is the Explanation of the Frank-Starling Mechanism When an extra amount of blood flows into the ventricles, the cardiac mu... Ventricular Function Curves Control of the Heart by the Sympathetic and Parasympathetic Nerves 10 - Rhythmical Excitation of the Heart Specialized Excitatory and Conductive System of the Heart Sinus (Sinoatrial) Node Mechanism of Sinus Nodal Rhythmicity. Figure 10-2 shows action potentials recorded from inside a sinus nodal fiber for three he... Leakiness of Sinus Nodal Fibers to Sodium and Calcium Causes Self-Excitation. Because of the high sodium ion concentration in t... Cause of the Slow Conduction. The slow conduction in the transitional, nodal, and penetrating A-V bundle fibers is caused mainl... The A-V Bundle Is Normally a One-Way Conduction Path. A special characteristic of the A-V bundle is the inability, except in ... Distribution of the Purkinje Fibers in the Ventricles—Left and Right Bundle Branches. After penetrating the fibrous tissue betwe... The Sinus Node is the Normal Pacemaker of the Heart Abnormal Pacemakers—Ectopic Pacemaker. Occasionally, some other part of the heart develops a rhythmical discharge rate that is ... Parasympathetic (Vagal) Stimulation Slows the Cardiac Rhythm and Conduction. Stimulation of the parasympathetic nerves to the he... Mechanism of the Vagal Effects. The acetylcholine released at the vagal nerve endings greatly increases the permeability of the ... Sympathetic Stimulation Increases the Cardiac Rhythm and Conduction. Sympathetic stimulation causes essentially the opposite eff... Mechanism of the Sympathetic Effect. Stimulation of the sympathetic nerves releases norepinephrine at the sympathetic nerve endi... 11 - Fundamentals of Electrocardiography Waveforms of the Normal Electrocardiogram Relation of the Monophasic Action Potential of Ventricular Muscle to the QRS and T Waves in the Standard Electrocardiogram. The ... Normal Voltages in the Electrocardiogram. The recorded voltages of the waves in the normal ECG depend on the manner in which the... P-Q or P-R Interval. The time between the beginning of the P wave and the beginning of the QRS complex is the interval between... Q-T Interval. Contraction of the ventricle lasts almost from the beginning of the Q wave (or R wave, if the Q wave is absent) t... Heart Rate as Determined from the Electrocardiogram. The rate of the heartbeat can be determined easily from an ECG because the ... Recording Electrical Potentials from a Partially Depolarized Mass of Syncytial Cardiac Muscle Flow of Electrical Currents in the Chest Around the Heart Electrocardiographic Leads Three Standard Bipolar Limb Leads Lead I. In recording limb lead I, the negative terminal of the electrocardiograph is connected to the right arm, and the positiv... Lead II. To record limb lead II, the negative terminal of the electrocardiograph is connected to the right arm and the positive ... Lead III. To record limb lead III, the negative terminal of the electrocardiograph is connected to the left arm, and the positiv... Einthoven’s Triangle. In Figure 11-6, the triangle, called Einthoven’s triangle, is drawn around the area of the heart. This tr... Einthoven’s Law. Einthoven’s law states that if the ECGs are recorded simultaneously with the three limb leads, the sum of the p... Normal Electrocardiograms Recorded from the Three Standard Bipolar Limb Leads. Figure 11-7 shows recordings of the ECGs in lead... Precordial Leads Augmented Limb Leads 12 - Electrocardiographic Interpretation of Cardiac Muscle and Coronary Blood Flow Abnormalities: Vectorial Analysis 13 - Cardiac Arrhythmias and Their Electrocardiographic Interpretation Abnormal Sinus Rhythms Tachycardia Bradycardia Bradycardia in Athletes. The well-trained athlete’s heart is often larger and considerably stronger than that of a normal perso... Vagal Stimulation Causes Bradycardia. Any circulatory reflex that stimulates the vagus nerves causes release of acetylcholine at... Sinus Arrhythmia Heart Block Within the Intracardiac Conduction Pathways Sinoatrial Block Atrioventricular Block Incomplete Atrioventricular Block First-Degree Block—Prolonged P-R Interval. The usual lapse of time between the beginning of the P wave and the beginning of th... Second-Degree Block. When conduction through the A-V bundle is slowed enough to increase the P-R interval to 0.25 to 0.45 sec... Complete A-V Block (Third-Degree Block). When the condition causing poor conduction in the A-V node or A-V bundle becomes se... Stokes-Adams Syndrome—Ventricular Escape. In some patients with A-V block, the total block comes and goes; that is, impulses a... Premature Contractions Causes of Premature Contractions Premature Atrial Contractions Pulse Deficit. When the heart contracts ahead of schedule, the ventricles will not have filled with blood normally, and the stro... Vector Analysis of the Origin of an Ectopic Premature Ventricular Contraction. In Chapter 12, the principles of vectorial analys... Disorders of Cardiac Repolarization—the Long QT Syndromes. Recall that the Q wave corresponds to ventricular depolarization, whe... Paroxysmal Tachycardia Paroxysmal Atrial Tachycardia Ventricular Tachycardia Ventricular Fibrillation Ventricular Defibrillation Atrial Fibrillation Atrial Flutter Cardiac Arrest 14 - Overview of the Circulation: Pressure, Flow, and Resistance Physical Characteristics of the Circulation Functional Parts of the Circulation. Before discussing the details of circulatory function, it is important to understand the ro... Volumes of Blood in the Different Parts of the Circulation. Figure 14-1 provides an overview of the circulation and lists the pe... Cross-Sectional Areas and Velocities of Blood Flow. If all the systemic vessels of each type were put side by side, their appro... Pressures in the Various Portions of the Circulation. Because the heart pumps blood continually into the aorta, the mean pressur... Basic Principles of Circulatory Function Interrelationships of Pressure, Flow, and Resistance Blood Flow Methods for Measuring Blood Flow. Many mechanical and mechanoelectrical flowmeter devices can be inserted in series with a blood... Electromagnetic Flowmeter. An electromagnetic flowmeter, the principles of which are illustrated in Figure 14-4, can be used to ... Ultrasonic Doppler Flowmeter. Another type of flowmeter that can be applied to the outside of the vessel and that has many of th... Laminar Flow of Blood in Vessels. When blood flows at a steady rate through a long smooth blood vessel, it flows in streamlines,... Parabolic Velocity Profile During Laminar Flow. When laminar flow occurs, the velocity of flow in the center of the vessel is fa... Turbulent Flow of Blood Under Some Conditions. When the rate of blood flow becomes too great, when it passes by an obstruction i... Blood Pressure Resistance to Blood Flow Units of Resistance. Resistance is the impediment to blood flow in a vessel, but it cannot be measured by any direct means. Inst... Expression of Resistance in CGS Units. Occasionally, a basic physical unit called the CGS (centimeters, grams, seconds) unit is ... Total Peripheral Vascular Resistance and Total Pulmonary Vascular Resistance. The rate of blood flow through the entire circulat... Conductance of Blood in a Vessel Is the Reciprocal of Resistance. Conductance is a measure of the blood flow through a vessel fo... Small Changes in Vessel Diameter Markedly Change Its Conductance. Slight changes in the diameter of a vessel cause tremendous ch... Poiseuille’s Law. The cause of this great increase in conductance when the diameter increases can be explained by referring to F... Importance of the Vessel Diameter Fourth Power Law in Determining Arteriolar Resistance. In the systemic circulation, about two ... Resistance to Blood Flow in Series and Parallel Vascular Circuits. Blood pumped by the heart flows from the high-pressure part ... Effect of Blood Hematocrit and Blood Viscosity on Vascular Resistance and Blood Flow Hematocrit—the Proportion of Blood That Is Red Blood Cells. If a person has a hematocrit of 40, this means that 40% of the blood... Increasing Hematocrit Markedly Increases Blood Viscosity. The viscosity of blood increases markedly as the hematocrit increases,... Effects of Pressure on Vascular Resistance and Tissue Blood Flow Autoregulation Attenuates the Effect of Arterial Pressure on Tissue Blood Flow. From the discussion thus far, one might expect a... Pressure-Flow Relationship in Passive Vascular Beds. In isolated blood vessels or in tissues that do not exhibit autoregulation... Vascular Wall Tension. Tension on the blood vessel wall develops in response to transmural pressure gradients and causes vascula... Vascular Shear Stress. As blood flows it creates a frictional force, or drag, on the endothelial cells lining the blood vessels ... 15 - Vascular Distensibility and Functions of the Arterial and Venous Systems Vascular Distensibility Units of Vascular Distensibility. Vascular distensibility normally is expressed as the fractional increase in volume for each mi... The Veins Are Much More Distensible Than the Arteries. The walls of the arteries are thicker and far stronger than those of the ... Effect of Sympathetic Stimulation or Sympathetic Inhibition on the Volume-Pressure Relationships of the Arterial and Venous Sys... Delayed Compliance (Stress-Relaxation) of Vessels. The term delayed compliance means that a vessel exposed to increased volume ... Arterial Pressure Pulsations Abnormal Pressure Pulse Contours Pressure Pulses Are Damped in the Smaller Arteries, Arterioles, and Capillaries. Figure 15-6 shows typical changes in the pressu... Auscultatory Method. Figure 15-7 shows the auscultatory method for determining systolic and diastolic arterial pressures. A stet... Automated Oscillometric Method. Systolic and diastolic arterial pressures are often measured using automated oscillometric devic... Normal Arterial Pressures as Measured by the Auscultatory and Oscillatory Methods. Figure 15-8 shows the approximate normal syst... Mean Arterial Pressure. The mean arterial pressure is the average of the arterial pressures measured millisecond by millisecond ... Veins and Their Functions Venous Resistance and Peripheral Venous Pressure Effect of High Right Atrial Pressure on Peripheral Venous Pressure. When the right atrial pressure rises above its normal value ... Effect of Intra-abdominal Pressure on Venous Pressures of the Leg. The pressure in the abdominal cavity of a recumbent person n... Effect of Gravitational Pressure on Venous Pressure Effect of the Gravitational Factor on Arterial and Other Pressures. The gravitational factor also affects pressures in the perip... Venous Valves and the Venous Pump: Their Effects on Venous Pressure Venous Valve Incompetence Causes Varicose Veins. The valves of the venous system may become incompetent or even be destroyed whe... Specific Blood Reservoirs Blood-Cleansing Function of the Spleen—Removal of Old Cells Blood cells passing through the splenic pulp before entering the si... Reticuloendothelial Cells of the Spleen. The pulp of the spleen contains many large phagocytic reticuloendothelial cells, and th... 16 - The Microcirculation and Lymphatic System: Capillary Fluid Exchange, Interstitial Fluid, and Lymph Flow Structure of the Microcirculation and Capillary System Structure of the Capillary Wall. Figure 16-2 shows the ultramicroscopic structure of typical endothelial cells in the capillary... Pores in the Capillary Membrane. Figure 16-2 shows two small passageways connecting the interior of the capillary with the exte... Special Types of Pores in Capillaries of Certain Organs. The pores in capillaries of some organs have special characteristics to... Flow of Blood in the Capillaries—Vasomotion Regulation of Vasomotion. The most important factor affecting the degree of opening and closing of the metarterioles and precapi... Average Function of the Capillary System. Despite the fact that blood flow through each capillary is intermittent, so many capil... Diffusion Through the Capillary Membrane Is the Most Important Means of Transferring Substances Between Plasma and Interstitia... Lipid-Soluble Substances Diffuse Directly Through the Cell Membranes of the Capillary Endothelium. If a substance is lipid-sol... Water-Soluble, Non–Lipid-Soluble Substances Diffuse Through Intercellular Pores in the Capillary Membrane. Many substances n... Effect of Molecular Size on Passage Through the Pores. The width of the capillary intercellular cleft pores, 6 to 7 nanometers, ... Diffusion Through the Capillary Membrane Is Proportional to the Concentration Difference Between the Two Sides of the Membrane. ... Interstitium and Interstitial Fluid Gel in the Interstitium. The fluid in the interstitium is derived by filtration and diffusion from the capillaries. It contains ... Fluid Filtration Across Capillaries Capillary Hydrostatic Pressure Interstitial Fluid Pressures in Tightly Encased Tissues. Some tissues of the body are surrounded by tight encasements, such as ... Summary: Interstitial Fluid Pressure in Loose Subcutaneous Tissue Usually Subatmospheric. Although the aforementioned different ... Pumping by the Lymphatic System—Basic Cause of the Negative Interstitial Fluid Pressure. The lymphatic system is discussed later... Plasma Colloid Osmotic Pressure Plasma Proteins Cause Colloid Osmotic Pressure. As discussed in Chapter 4, only the molecules or ions that fail to pass through ... Normal Values for Plasma Colloid Osmotic Pressure. The colloid osmotic pressure of normal human plasma averages about 28 mm Hg; ... Analysis of the Forces Causing Filtration at the Arterial End of the Capillary. The approximate average forces operative at the... Analysis of Reabsorption at the Venous End of the Capillary. The low blood pressure at the venous end of the capillary changes t... Capillary Filtration Coefficient Lymphatic System Lymph Channels of the Body Formation of Lymph Rate of Lymph Flow Effect of Interstitial Fluid Pressure on Lymph Flow. Figure 16-8 shows the effect of different levels of interstitial fluid hyd... Lymphatic Pump Increases Lymph Flow. Valves exist in all lymph channels. Figure 16-9 shows typical valves for collecting lympha... Pumping Caused by External Intermittent Compression of the Lymphatics. In addition to the pumping caused by intrinsic intermitte... Lymphatic Capillary Pump. The terminal lymphatic capillary is also capable of pumping lymph, in addition to the pumping by the l... Summary of Factors That Determine Lymph Flow. From the previous discussion, one can see that the two primary factors that determ... Lymphatic System Plays a Key Role in Controlling Interstitial Fluid Protein Concentration, Volume, and Pressure Significance of Negative Interstitial Fluid Pressure for Holding Body Tissues Together 17 - Local and Humoral Control of Tissue Blood Flow Local Control of Blood Flow in Response to Tissue Needs Variations in Blood Flow in Different Tissues and Organs. Note the very large blood flows listed in Table 17-1 for some organs... Mechanisms of Blood Flow Control Acute Control of Local Blood Flow Increases in Tissue Metabolism Increase Tissue Blood Flow Reduced Oxygen Availability Increases Tissue Blood Flow. One of the most necessary of the metabolic nutrients is oxygen. Wheneve... Vasodilator Theory for Acute Local Blood Flow Regulation—Possible Special Role of Adenosine. According to the vasodilator theory... Oxygen Demand Theory for Local Blood Flow Control. Although the vasodilator theory is widely accepted, several critical facts h... Possible Role of Other Nutrients Besides Oxygen in Control of Local Blood Flow. Under special conditions, it has been shown that... Special Examples of Acute Metabolic Control of Local Blood Flow Reactive Hyperemia Occurs After Tissue Blood Supply Is Blocked for a Short Time. When the blood supply to a tissue is blocked fo... Active Hyperemia Occurs When Tissue Metabolic Rate Increases. When a tissue becomes highly active, such as an exercising muscle,... Autoregulation of Blood Flow During Changes in Arterial Pressure—Metabolic and Myogenic Mechanisms Special Mechanisms for Acute Blood Flow Control in Specific Tissues Control of Tissue Blood Flow: Endothelium-Derived Relaxing or Constricting Factors Nitric Oxide Is a Vasodilator Released from Healthy Endothelial Cells. The most important of the endothelium-derived relaxing ... Endothelin Is a Powerful Vasoconstrictor Released From Damaged Endothelium. Endothelial cells also release vasoconstrictor subst... Long-Term Blood Flow Regulation Blood Flow Regulation by Changes in Tissue Vascularity Role of Oxygen in Long-Term Regulation. Oxygen is important not only for acute control of local blood flow but also for long-t... Importance of Vascular Growth Factors in Formation of New Blood Vessels. A dozen or more factors that increase growth of new blo... Vascularity Determined by Maximum Blood Flow Need, Not by Average Need. An especially valuable characteristic of long-term vasc... Blood Flow Regulation by Development of Collateral Circulation Vascular Remodeling in Response to Chronic Changes in Blood Flow or Blood Pressure Humoral Control of the Circulation VasoconstrictorS Norepinephrine and Epinephrine. Norepinephrine is an especially powerful vasoconstrictor hormone; epinephrine is less powerful a... Angiotensin II. Angiotensin II is another powerful vasoconstrictor substance. As little as one millionth of a gram can increase ... Vasopressin. Vasopressin, also called antidiuretic hormone, is even more powerful than angiotensin II as a vasoconstrictor, thus... Vasodilators Bradykinin. Several substances called kinins cause powerful vasodilation when formed in the blood and tissue fluids of some orga... Histamine. Histamine is released in almost every tissue of the body if the tissue becomes damaged or inflamed or is the subject ... Most Vasodilators or Vasoconstrictors Have Little Effect on Long-Term Blood Flow Unless They Alter the Metabolic Rate of the T... 18 - Nervous Regulation of the Circulation and Rapid Control of Arterial Pressure Nervous Regulation of the Circulation Autonomic Nervous System Sympathetic Nervous System. Figure 18-1 shows the anatomy of sympathetic nervous control of the circulation. Sympathetic vasomo... Sympathetic Innervation of the Blood Vessels. Figure 18-2 shows the distribution of sympathetic nerve fibers to the blood vesse... Sympathetic Stimulation Increases Heart Rate and Contractility. Sympathetic fibers also go directly to the heart, as shown in Fi... Parasympathetic Stimulation Decreases Heart Rate and Contractility. Although the parasympathetic nervous system is exceedingly i... Sympathetic Vasoconstrictor System and Its Control by the Central Nervous System Vasomotor Center in the Brain and Its Control of the Vasoconstrictor System. Located bilaterally mainly in the reticular substan... Continuous Partial Constriction of Blood Vessels by Sympathetic Vasoconstrictor Tone. Under normal conditions, the vasoconstrict... Control of Heart Activity by the Vasomotor Center. At the same time that the vasomotor center regulates the amount of vascular c... Control of the Vasomotor Center by Higher Nervous Centers. Large numbers of small neurons located throughout the reticular subs... Norepinephrine Is the Sympathetic Vasoconstrictor Neurotransmitter. The substance secreted at the endings of the vasoconstricto... Adrenal Medullae and Their Relationship to the Sympathetic Vasoconstrictor System. Sympathetic impulses are transmitted to the a... Role of the Nervous System in Rapid Control of Arterial Pressure Nervous Control of Arterial Pressure Is Rapid. An especially important characteristic of nervous control of arterial pressure is... Reflex Mechanisms for Maintaining Normal Arterial Pressure Baroreceptor Arterial Pressure Control System—Baroreceptor Reflexes Physiologic Anatomy of the Baroreceptors and Their Innervation. Baroreceptors are spray-type nerve endings that lie in the wall... Response of the Baroreceptors to Changes in Arterial Pressure. Figure 18-6 shows the effects of different arterial pressure lev... Circulatory Reflex Initiated by the Baroreceptors. After the baroreceptor signals have entered the nucleus tractus solitarius of... Baroreceptors Attenuate Blood Pressure Changes During Changes in Body Posture. The ability of the baroreceptors to maintain rela... Pressure Buffer Function of the Baroreceptor Control System. Because the baroreceptor system opposes increases or decreases in a... Are the Baroreceptors Important in Long-Term Regulation of Arterial Pressure Although the arterial baroreceptors provide power... Control of Arterial Pressure by the Carotid and Aortic Chemoreceptors—Effect of Low Oxygen on Arterial Pressure. Closely associa... Atrial and Pulmonary Artery Reflexes Regulate Arterial Pressure. The atria and pulmonary arteries have stretch receptors in thei... Atrial Reflexes That Activate the Kidneys—The Volume Reflex. Stretch of the atria and activation of low-pressure atrial recept... Increased Atrial Pressure Raises Heart Rate—Bainbridge Reflex. Increases in atrial pressure sometimes increase the heart rate as... Importance of CNS Ischemic Response as a Regulator of Arterial Pressure. Despite the powerful nature of the CNS ischemic respons... Cushing Reaction to Increased Pressure Around the Brain. The Cushing reaction is a special type of CNS ischemic response that re... Role of the Skeletal Nerves and Skeletal Muscles in Increasing Cardiac Output and Arterial Pressure Abdominal Compression Reflex Increases Cardiac Output and Arterial Pressure. When a baroreceptor or chemoreceptor reflex is elic... Skeletal Muscle Contraction Increases Cardiac Output and Arterial Pressure During Exercise. When the skeletal muscles contract ... Arterial Pressure Vasomotor Waves—Oscillation of Pressure Reflex Control Systems Oscillation of Baroreceptor and Chemoreceptor Reflexes. The vasomotor waves of Figure 18-11B are often seen in experimental pre... Oscillation of CNS Ischemic Response. The record in Figure 18-11A resulted from oscillation of the CNS ischemic pressure contro... 19 - Role of the Kidneys in Long-Term Control of Arterial Pressure and in Hypertension: The Integrated System for Arterial Pressure Regulation Renal–Body Fluid System for Arterial Pressure Control Figure 19-1 shows the approximate average effect of different arterial pressure levels on the renal output of salt and water by... Experiment Demonstrating the Renal–Body Fluid System for Arterial Pressure Control. Figure 19-2 shows the results of an experim... Renal–Body Fluid Mechanism Provides Nearly Infinite Feedback Gain for Long-term Arterial Pressure Control. Figure 19-1 shows t... Two Key Determinants of Long-Term Arterial Pressure. In Figure 19-1, one can also see that two basic long-term factors determ... Chronic Renal Output Curve Much Steeper Than the Acute Curve. An important characteristic of pressure natriuresis (and pressure ... Failure of Increased Total Peripheral Resistance to Elevate Long-Term Level of Arterial Pressure if Fluid Intake and Renal Func... Increased Fluid Volume Can Elevate Arterial Pressure by Increasing Cardiac Output or Total Peripheral Resistance Importance of Salt (NaCl) in the Renal–Body Fluid Schema for Arterial Pressure Regulation Experimental Volume-Loading Hypertension Caused by Reduced Kidney Mass and Increased Salt Intake. Figure 19-7 shows a typical ... Sequential Changes in Circulatory Function During Development of Volume-Loading Hypertension. It is especially instructive to s... Volume-Loading Hypertension in Patients Who Have No Kidneys but Are Being Maintained With an Artificial Kidney Hypertension Caused by Excess Aldosterone Role of the Renin-Angiotensin System in Arterial Pressure Control Rapidity and Intensity of the Vasoconstrictor Pressure Response to the Renin-Angiotensin System Angiotensin II Causes Renal Retention of Salt and Water—An Important Means for Long-Term Control of Arterial Pressure Mechanisms of the Direct Renal Effects of Angiotensin II to Cause Renal Retention of Salt and Water. Angiotensin has several dir... Angiotensin II Increases Kidney Salt and Water Retention by Stimulating Aldosterone. Angiotensin II is also one of the most pow... Role of the Renin-Angiotensin System in Maintaining a Normal Arterial Pressure Despite Large Variations in Salt Intake One-Kidney Goldblatt Hypertension. When one kidney is removed, and a constrictor is placed on the renal artery of the remaining... Two-Kidney Goldblatt Hypertension. Hypertension also can result when the artery to only one kidney is constricted while the art... Hypertension Caused by Diseased Kidneys That Secrete Renin Chronically. Often, patchy areas of one or both kidneys are diseased ... Primary (Essential) Hypertension Graphic Analysis of Arterial Pressure Control in Essential Hypertension. Figure 19-15 is a graphic analysis of essential hypert... Treatment of Essential Hypertension. As a first step, current guidelines for treating hypertension recommend lifestyle modificat... Summary of Integrated Multifaceted Systems for Arterial Pressure Regulation Arterial Pressure Control Mechanisms That Act Within Seconds or Minutes. The rapidly acting pressure control mechanisms are almo... Arterial Pressure Control Mechanisms That Act After Many Minutes. Several pressure control mechanisms exhibit significant respon... Long-Term Mechanisms for Arterial Pressure Regulation. The goal of this chapter has been to explain the role of the kidneys in ... 20 - Cardiac Output, Venous Return, and Their Regulation Normal Values for Cardiac Output at Rest and During Activity Control of Cardiac Output by Venous Return—Frank-Starling Mechanism of the Heart Cardiac Output Is the Sum of All Tissue Blood Flows—Tissue Metabolism Regulates Most Local Blood Flow Limits for the Cardiac Output Factors That Cause a Hypereffective Heart Nervous Excitation Can Increase Heart Pumping. In Chapter 9, we saw that a combination of sympathetic stimulation and parasympat... Heart Hypertrophy Can Increase Pumping Effectiveness. A long-term increased workload, but not so much excess load that it damag... Factors That Cause a Hypoeffective Heart Nervous System Regulation of Cardiac Output Importance of Nervous System For Maintaining Arterial Pressure When Peripheral Blood Vessels Are Dilated and Venous Return and C... Effect of Nervous System to Increase Arterial Pressure During Exercise. During exercise, intense increases in metabolism in acti... Effect of External Pressure Outside the Heart on Cardiac Output Curves. Figure 20-8 shows the effect of changes in external car... Combinations of Different Patterns of Cardiac Output Curves. Figure 20-9 shows that the final cardiac output curve can change a... Venous Return Curves Normal Venous Return Curve Plateau in Venous Return Curve at Negative Atrial Pressures Caused by Collapse of the Large Veins. When the right atrial pressur... Mean Circulatory Filling Pressure, Mean Systemic Filling Pressure—Effects on Venous Return Increased Blood Volume Raises Mean Circulatory Filling Pressure. The greater the volume of blood in the circulation, the greater... Sympathetic Nervous Stimulation Increases Mean Circulatory Filling Pressure. The green curve and blue curve in Figure 20-11 sho... Mean Systemic Filling Pressure and Relationship to Mean Circulatory Filling Pressure. The mean systemic filling pressure (Psf) i... Effect on Venous Return Curve of Changes in Mean Systemic Filling Pressure. Figure 20-12 shows the effects on the venous return... When Pressure Gradient for Venous Return Is Zero There Is No Venous Return. When the right atrial pressure rises to equal the Ps... Resistance to Venous Return Effect of Resistance to Venous Return on the Venous Return Curve. Figure 20-13 demonstrates the effect of different levels of r... Combinations of Venous Return Curve Patterns. Figure 20-14 shows the effects on the venous return curve caused by simultaneous ... Effect of Increased Blood Volume on Cardiac Output. A sudden increase in blood volume of about 20% increases the cardiac output ... Compensatory Effects Initiated in Response to Increased Blood Volume. The greatly increased cardiac output caused by increased b... Effect of Sympathetic Stimulation on Cardiac Output. Sympathetic stimulation affects the heart and systemic circulation: (1) it ... Effect of Sympathetic Inhibition on Cardiac Output. The sympathetic nervous system can be blocked by inducing total spinal anest... Effect of Opening a Large Arteriovenous Fistula. Figure 20-17 shows various stages of circulatory changes that occur after open... Other Analyses of Cardiac Output Regulation. In Chapter 21, analysis of cardiac output regulation during exercise is presented. ... Methods For Measuring Cardiac Output Pulsatile Output of the Heart Measured by Electromagnetic or Ultrasonic Flowmeter Measurement of Cardiac Output Using the Oxygen Fick Principle Indicator Dilution Method Echocardiography Thoracic Electrical Bioimpedance Method Bibliography 21 - Muscle Blood Flow and Cardiac Output During Exercise; the Coronary Circulation and Ischemic Heart Disease Blood Flow Regulation in Skeletal Muscle at Rest and During Exercise Skeletal Muscle Blood Flow Rate Blood Flow During Muscle Contractions. Figure 21-1 shows a record of blood flow changes in a calf muscle of a leg during strong... Increased Blood Flow in Muscle Capillaries During Exercise. During rest, some muscle capillaries have little or no flowing blood... Control of Skeletal Muscle Blood Flow Decreased Oxygen in Muscle Greatly Enhances Flow. The large increase in muscle blood flow that occurs during skeletal muscle act... Effects of Sympathetic Activation Sympathetic Stimulation May Increase Arterial Pressure During Exercise Why Is Increased Arterial Pressure During Exercise Important When muscles are stimulated maximally in a laboratory experiment, b... Importance of Increased Cardiac Output During Exercise Graphic Analysis of Changes in Cardiac Output During Heavy Exercise. Figure 21-2 shows a graphic analysis of the large increas... Coronary Circulation Cardiac Muscle Compression Causes Phasic Changes in Coronary Blood Flow During Systole and Diastole. Figure 21-4 shows the chan... Control of Coronary Blood Flow Local Muscle Metabolism Is the Primary Controller of Coronary Flow Nervous Control of Coronary Blood Flow Direct Effects of Nervous Stimuli on Coronary Vasculature. The distribution of parasympathetic (vagal) nerve fibers to the vent... Ischemic Heart Disease Acute Coronary Artery Occlusion Lifesaving Value of Collateral Circulation in the Heart. The degree of damage to the heart muscle caused by slowly developing at... Myocardial Infarction Subendocardial Infarction. The subendocardial muscle frequently becomes infarcted, even when there is no evidence of infarction ... Decreased Cardiac Output—Systolic Stretch and Cardiac Shock. When some of the cardiac muscle fibers are not functioning and oth... Damming of Blood in the Body’s Venous System. When the heart is not pumping blood forward, it must be damming blood in the atria... Fibrillation of the Ventricles After Myocardial Infarction. In many people who die of coronary occlusion, death occurs because o... Rupture of Infarcted Area. During the first day or so after an acute infarct, there is little danger of rupture of the ischemic ... Replacement of Dead Muscle by Scar Tissue. In the lower part of Figure 21-8, the various stages of recovery after a large myoca... Value of Rest in Treating Myocardial Infarction. The degree of cardiac cellular death is determined by the degree of ischemia an... Pain in Coronary Heart Disease Angina Pectoris (Cardiac Pain). In most people who sustain progressive constriction of their coronary arteries, cardiac pain, ca... Drug Treatment. Several vasodilator drugs, when administered during an acute anginal attack, can often provide immediate relief ... Surgical Treatment of Coronary Artery Disease Aortic-Coronary Bypass Surgery. In many patients with coronary ischemia, the constricted areas of the coronary arteries are loc... 22 - Cardiac Failure 23 - Heart Valves and Heart Sounds; Valvular and Congenital Heart Defects 24 - Circulatory Shock and Its Treatment Physiological Causes of Shock Circulatory Shock Caused by Decreased Cardiac Output Stages of Shock Shock Caused by Hypovolemia—Hemorrhagic Shock Relationship of Bleeding Volume to Cardiac Output and Arterial Pressure Sympathetic Reflex Compensations in Shock—Their Special Value to Maintain Arterial Pressure. The decrease in arterial pressure a... Greater Effect of Sympathetic Nervous Reflexes in Maintaining Arterial Pressure Than in Maintaining Cardiac Output. Referring ag... Protection of Coronary and Cerebral Blood Flow by the Reflexes. A special value of the maintenance of normal arterial pressure, ... Nonprogressive Shock—Compensated Shock Progressive Shock—Caused by Vicious Cycle of Cardiovascular Deterioration Cardiac Depression. When the arterial pressure falls low enough, coronary blood flow decreases below that required for adequate ... Vasomotor Failure. In the early stages of shock, various circulatory reflexes cause intense activity of the sympathetic nervous ... Blockage of Very Small Vessels by Sludged Blood. In time, blockage occurs in many of the very small blood vessels in the circula... Increased Capillary Permeability. After many hours of capillary hypoxia and lack of other nutrients, the permeability of the cap... Release of Toxins by Ischemic Tissue. Shock has been suggested to cause tissues to release toxic substances, such as histamine, ... Cardiac Depression Caused by Endotoxin. Endotoxin is released from the bodies of dead gram-negative bacteria in the intestines.... Generalized Cellular Deterioration. As shock becomes severe, many signs of generalized cellular deterioration occur throughout t... Patchy Areas of Tissue Necrosis Caused by Patchy Blood Flows in Different Organs. Not all cells of the body are equally damaged ... Acidosis in Shock. Metabolic derangements that occur in shocked tissue can lead to acidosis throughout the body. This results fr... Positive Feedback Deterioration of Tissues in Shock and Vicious Cycle of Progressive Shock. All the factors just discussed that ... Irreversible Shock Neurogenic Shock—Increased Vascular Capacity Anaphylactic Shock and Histamine Shock Septic Shock Physiology of Treatment in Shock Replacement Therapy Blood and Plasma Transfusion. If a person is in shock caused by hemorrhage, the best possible therapy is usually transfusion of ... Dextran Solution as a Plasma Substitute. The principal requirement of a truly effective plasma substitute is that it remain in t... Other Therapy Treatment by the Head-Down Position. When the pressure falls too low in most types of shock, especially in hemorrhagic and neur... Oxygen Therapy. Because a major deleterious effect of most types of shock is too little delivery of oxygen to the tissues, givin... Treatment With Glucocorticoids. Glucocorticoids—adrenal cortex hormones that control glucose metabolism—are frequently given to ... Circulatory Arrest 25 - Regulation of Body Fluid Compartments: Extracellular and Intracellular Fluids; Edema Fluid Intake and Output ARE Balanced During Steady-State Conditions Daily Intake of Water Daily Loss of Body Water Insensible Water Loss. Some water losses cannot be precisely regulated. For example, humans experience continuous water loss by ... Fluid Loss in Sweat. The amount of water lost by sweating is highly variable, depending on physical activity and environmental t... Water Loss in Feces. Only a small amount of water (100 ml/day) normally is lost in the feces. This loss can increase to several ... Water Loss by the Kidneys. The remaining water loss from the body occurs in the urine excreted by the kidneys. Multiple mechanis... Body Fluid Compartments Intracellular Fluid Compartment Extracellular Fluid Compartment Blood Volume Constituents of Extracellular and Intracellular Fluids Intracellular Fluid Constituents Measurement of Body Fluid Compartment Volumes—Indicator-Dilution Principle Determination of Volumes of Specific Body Fluid Compartments Measurement of Total Body Water. Radioactive water (tritium, 3H2O) or heavy water (deuterium, 2H2O) can be used to measure total... Measurement of Extracellular Fluid Volume. The volume of extracellular fluid can be estimated using any of several substances th... Calculation of Intracellular Volume. The intracellular volume cannot be measured directly. However, it can be calculated as foll... Measurement of Plasma Volume. Plasma volume can be measured using a substance that does not readily penetrate capillary membrane... Calculation of Interstitial Fluid Volume. Interstitial fluid volume cannot be measured directly, but it can be calculated as fol... Measurement of Blood Volume. If one measures the hematocrit (the fraction of the total blood volume composed of cells) and plasm... Fluid Exchange and Osmotic Equilibrium Between Intracellular and Extracellular Fluid Osmolality and Osmolarity. The osmolal concentration of a solution is called osmolality when the concentration is expressed as o... Calculation of the Osmolarity and Osmotic Pressure of a Solution. Using the van’t Hoff law, one can calculate the potential osmo... Osmolarity of Body Fluids. Referring back to Table 25-2, note the approximate osmolarity of the various osmotically active subs... Corrected Osmolar Activity of Body Fluids. At the bottom of Table 25-2 are shown corrected osmolar activities of plasma, inters... Osmotic Equilibrium Between Intracellular and Extracellular Fluids Isotonic, Hypotonic, and Hypertonic Fluids. The effects of different concentrations of impermeant solutes in the extracellular f... Isosmotic, Hyperosmotic, and Hypo-Osmotic Fluids. The terms isotonic, hypotonic, and hypertonic refer to whether solutions will... Osmotic Equilibrium Between Intracellular and Extracellular Fluids Is Rapidly Attained. Transfer of fluid across the cell membr... Volume and Osmolality of Extracellular and Intracellular Fluids in Abnormal States Effect of Adding Saline Solution to the Extracellular Fluid Glucose and Other Solutions Administered For Nutritive Purposes Clinical Abnormalities of Fluid Volume Regulation: Hyponatremia and Hypernatremia Causes of Hyponatremia: Excess Water or Loss of Sodium Hyponatremia Causes Cell Edema Causes of Hypernatremia: Water Loss or Excess Sodium Hypernatremia Causes Cell Shrinkage Edema: Excess Fluid in the Tissues Intracellular Edema Extracellular Edema Factors That Can Increase Capillary Filtration Lymphedema—Failure of Lymph Vessels to Return Fluid and Protein to the Blood Summary of Causes of Extracellular Edema Edema Caused by Heart Failure. One of the most serious and common causes of edema is heart failure, which was discussed in Chapt... Edema Caused by Decreased Kidney Excretion of Salt and Water. Most sodium chloride added to the blood remains in the extracellul... Edema Caused by Decreased Plasma Proteins. Failure to produce normal amounts of proteins or leakage of proteins from the plasma ... Safety Factor Caused by Low Compliance of the Interstitium in the Negative Pressure Range Importance of Interstitial Gel in Preventing Fluid Accumulation in the Interstitium. Note in Figure 25-8 that in normal tissue... Importance of Proteoglycan Filaments as a Spacer for Cells and in Preventing Rapid Flow of Fluid in Tissues. The proteoglycan f... Increased Lymph Flow as a Safety Factor Against Edema Washdown of Interstitial Fluid Protein as a Safety Factor Against Edema Fluids in Potential Spaces of the Body Fluid Is Exchanged Between Capillaries and Potential Spaces. The surface membrane of a potential space usually does not offer si... Lymphatic Vessels Drain Protein From the Potential Spaces. Proteins collect in the potential spaces because of leakage out of th... Edema Fluid in the Potential Spaces Is Called Effusion. When edema occurs in the subcutaneous tissues adjacent to the potential... 26 - The Urinary System: Functional Anatomy and Urine Formation by the Kidneys Multiple Functions of the Kidneys Excretion of Metabolic Waste Products, Foreign Chemicals, Drugs, and Hormone Metabolites. The kidneys are the primary means for ... Regulation of Water and Electrolyte Balances. For maintenance of homeostasis, excretion of water and electrolytes must match in... Regulation of Arterial Pressure. As discussed in Chapter 19, the kidneys play a dominant role in long-term regulation of arteri... Regulation of Acid–Base Balance. The kidneys contribute to acid–base regulation, along with the lungs and body fluid buffers, b... Regulation of Erythrocyte Production. The kidneys secrete erythropoietin, which stimulates production of red blood cells by hema... Regulation of 1,25-Dihydroxyvitamin D3 Production. The kidneys produce 1,25-dihydroxyvitamin D3 (calcitriol), the active form ... Glucose Synthesis. The kidneys synthesize glucose from amino acids and other precursors during prolonged fasting, a process refe... General Organization of the Kidneys and Urinary Tract Renal Blood Supply Micturition Innervation of the Bladder. The principal nerve supply of the bladder is via the pelvic nerves, which connect with the spinal co... Micturition Reflex Urine Formation Results from Glomerular Filtration, Tubular Reabsorption, and Tubular Secretion 27 - Glomerular Filtration, Renal Blood Flow, and Their Control Glomerular Filtration—The First Step in Urine Formation Glomerular Capillary Membrane Filterability of Solutes Inversely Related to Their Size. The glomerular capillary membrane is thicker than most other capillari... Negatively Charged Large Molecules Are Filtered Less Easily Than Positively Charged Molecules of Equal Molecular Size. The molec... Minimal-Change Nephropathy and Increased Glomerular Permeability to Plasma Proteins. In minimal-change nephropathy, the glomer... Determinants of the Glomerular Filtration Rate Renal Blood Flow Determinants of Renal Blood Flow Physiological Control of Glomerular Filtration and Renal Blood Flow Norepinephrine, Epinephrine, and Endothelin Constrict Renal Blood Vessels and Decrease Glomerular Filtration Rate. Hormones tha... Angiotensin II Preferentially Constricts Efferent Arterioles in Most Physiological Conditions. A powerful renal vasoconstrictor... Endothelial-Derived Nitric Oxide Decreases Renal Vascular Resistance and Increases Glomerular Filtration Rate. An autacoid t... Prostaglandins and Bradykinin Decrease Renal Vascular Resistance and Tend to Increase Glomerular Filtration Rate. Prostaglandi... Autoregulation of Glomerular Filtration Rate and Renal Blood Flow Importance of Glomerular Filtration Rate Autoregulation in Preventing Extreme Changes in Renal Excretion 28 - Renal Tubular Reabsorption and Secretion Tubular Reabsorption is Quantitatively Large and Highly Selective Tubular Reabsorption Includes Passive and Active Mechanisms Active Transport Reabsorption and Secretion Along Different Parts of the Nephron Proximal Tubular Reabsorption Distal Tubules Medullary Collecting Ducts Regulation of Tubular Reabsorption Use of Clearance Methods to Quantify Kidney Function 29 - Urine Concentration and Dilution; Regulation of Extracellular Fluid Osmolarity and Sodium Concentration Kidneys Excrete Excess Water by Forming Dilute Urine Tubular Fluid Remains Isosmotic in Proximal Tubules. As fluid flows through the proximal tubule, solutes and water are reabsorbe... Tubular Fluid Is Diluted in the Ascending Loop of Henle. In the ascending limb of the loop of Henle, especially in the thick seg... Tubular Fluid in Distal and Collecting Tubules Is Further Diluted in Absence of ADH. As the dilute fluid in the early distal tub... Kidneys Conserve Water by Excreting Concentrated Urine Countercurrent Multiplier Mechanism Produces Hyperosmotic Renal Medullary Interstitium Loop of Henle Characteristics That Cause Solutes to be Trapped in the Renal Medulla Steps Involved in Causing Hyperosmotic Renal Medullary Interstitium. Keeping in mind these characteristics of the loop of Henle,... Recirculation of Urea from Collecting Duct to Loop of Henle Contributes to Hyperosmotic Renal Medulla. A healthy person usually ... Increased Medullary Blood Flow Reduces Urine-Concentrating Ability. Certain vasodilators can markedly increase renal medullary ... Proximal Tubule. About 65% of most filtered electrolytes is reabsorbed in the proximal tubule. However, the proximal tubular mem... Descending Loop of Henle. As fluid flows down the descending loop of Henle, water is absorbed into the medulla. The descending l... Thin Ascending Loop of Henle. The thin ascending limb is essentially impermeable to water but reabsorbs some sodium chloride. Be... Thick Ascending Loop of Henle. The thick part of the ascending loop of Henle is also virtually impermeable to water, but large a... Early Distal Tubule. The early distal tubule has properties similar to those of the thick ascending loop of Henle, so further di... Late Distal Tubule and Cortical Collecting Tubules. In the late distal tubule and cortical collecting tubules, the osmolarity of... Inner Medullary Collecting Ducts. The concentration of fluid in the inner medullary collecting ducts also depends on the followi... Control of Extracellular Fluid Osmolarity and Sodium Concentration Osmoreceptor-ADH Feedback System Other Stimuli for ADH Secretion Importance of Thirst in Controlling Extracellular Fluid Osmolarity and Sodium Concentration Stimuli for Thirst 30 - Renal Regulation of Potassium, Calcium, Phosphate, and Magnesium; Integration of Renal Mechanisms for Control of Blood Volume and Extracellular Fluid Volume Regulation of Extracellular Fluid Potassium Concentration and Potassium Excretion Insulin Stimulates Potassium Uptake Into Cells. Insulin stimulates sodium-potassium adenosine triphosphatase (ATPase) activity... Aldosterone Increases Potassium Uptake Into Cells. Increased potassium intake also stimulates secretion of aldosterone, which in... β-Adrenergic Stimulation Increases Cellular Uptake of Potassium. Increased secretion of catecholamines, especially epinephrine,... Acid–Base Abnormalities Can Cause Changes in Potassium Distribution. Metabolic acidosis increases extracellular potassium concen... Cell Lysis Causes Increased Extracellular Potassium Concentration. As cells are destroyed, the large amounts of potassium contai... Strenuous Exercise Can Cause Hyperkalemia by Releasing Potassium From Skeletal Muscle. During prolonged exercise, potassium is r... Increased Extracellular Fluid Osmolarity Causes Redistribution of Potassium From Cells to Extracellular Fluid. Increased extrace... Variable Potassium Secretion in Distal and Collecting Tubules Mediates Most Daily Changes in Potassium Excretion. The most impor... Control of Potassium Secretion by Principal Cells. The primary factors that control potassium secretion by the principal cells o... Intercalated Cells Can Reabsorb or Secrete Potassium. In circumstances associated with severe potassium depletion, there is a ce... Increased Extracellular Fluid Potassium Concentration Stimulates Potassium Secretion. The rate of potassium secretion in the lat... Aldosterone Stimulates Potassium Secretion. Aldosterone stimulates active reabsorption of sodium ions by the principal cells of ... Increased Extracellular Potassium Ion Concentration Stimulates Aldosterone Secretion. In negative feedback control systems, the ... Blockade of Aldosterone Feedback System Greatly Impairs Potassium Regulation. In the absence of aldosterone secretion, as occurs... Increased Distal Tubular Flow Rate Stimulates Potassium Secretion. A rise in distal tubular flow rate, as occurs with volume exp... Acute Acidosis Decreases Potassium Secretion. Acute increases in extracellular fluid hydrogen ion concentration (acidosis) reduc... Regulation of Renal Calcium Excretion and Extracellular Calcium Ion Concentration Proximal Tubular Calcium Reabsorption. Most of the calcium reabsorption in the proximal tubule occurs through the paracellular p... Loop of Henle and Distal Tubule Calcium Reabsorption. In the loop of Henle, calcium reabsorption is restricted to the thick asce... Regulation of Tubular Calcium Reabsorption. One of the primary controllers of renal tubular calcium reabsorption is PTH. Increas... Regulation of Renal Phosphate Excretion Regulation of Renal Magnesium Excretion and Extracellular Magnesium Ion Concentration Integration of Renal Mechanisms for Control of Extracellular Fluid Importance of Pressure Natriuresis and Pressure Diuresis in Maintaining Body Sodium and Fluid Balance Pressure Natriuresis and Diuresis: Key Components of A Renal–Body Fluid Feedback for Regulating Body Fluid Volumes and Arterial ... Distribution of Extracellular Fluid Between Interstitial Spaces and Vascular System Nervous and Hormonal Factors Increase Effectiveness of Renal–Body Fluid Feedback Control Integrated Responses to Changes in Sodium Intake Conditions That Cause Large Increases in Blood Volume and Extracellular Fluid Volume Conditions That Cause Large Increases in Extracellular Fluid Volume With Normal or Reduced Blood Volume 31 - Acid–Base Regulation Hydrogen Ion Concentration is Precisely Regulated Acids and Bases—Definitions and Meanings Strong and Weak Acids and Bases. A strong acid, such as HCl, rapidly dissociates and releases especially large amounts of H+ in ... Defending Against Changes in H+ Concentration: Buffers, Lungs, and Kidneys Buffering of H+ in the Body Fluids Bicarbonate Buffer System Phosphate Buffer System Proteins are Important Intracellular Buffers Respiratory Regulation of Acid–Base Balance Feedback Control of H+ Concentration by the Respiratory System. Because increased H+ concentration stimulates respiration and be... Efficiency of Respiratory Control of H+ Concentration. Respiratory control cannot return the H+ concentration all the way back t... Buffering Power of the Respiratory System. Respiratory regulation of acid–base balance is a physiological type of buffer system ... Impairment of Lung Function Can Cause Respiratory Acidosis. We have discussed thus far the role of the normal respiratory mechan... Renal Control of Acid–Base Balance Secretion of H+ and Reabsorption of HCO3− by the Renal Tubules Combination of Excess H+ with Phosphate and Ammonia Buffers In the Tubule Generates “New” HCO3− Quantifying Renal Acid–Base Excretion Regulation of Renal Tubular H+ Secretion Renal Correction of Acidosis—Increased Excretion of H+ and Addition of HCO3− to the Extracellular Fluid Renal Correction of Alkalosis—Decreased Tubular Secretion of H+ and Increased Excretion of HCO3− 32 - Diuretics and Kidney Diseases 33 - Red Blood Cells, Anemia, and Polycythemia Red Blood Cells (Erythrocytes) Shape and Size of Red Blood Cells. Normal RBCs, shown in Figure 33-3, are biconcave discs having a mean diameter of about 7.8 m... Concentration of Red Blood Cells in the Blood. In healthy men, the average number of RBCs per cubic millimeter is 5,200,000 (±30... Quantity of Hemoglobin in the Cells. RBCs can concentrate hemoglobin in the cell fluid up to about 34 g/100 ml of cells. The con... Production of Red Blood Cells Areas of the Body That Produce Red Blood Cells. In the early weeks of embryonic life, primitive nucleated RBCs are produced in t... Stages of Differentiation of Red Blood Cells Erythropoietin Regulates Red Blood Cell Production Tissue Oxygenation—Essential Regulator of Red Blood Cell Production. Conditions that decrease the quantity of oxygen transported... Hypoxia Increases Formation of Erythropoietin Which Stimulates Red Blood Cell Production. The principal stimulus for RBC product... Erythropoietin Is Formed Mainly in the Kidneys. Normally, about 90% of all erythropoietin is formed in the kidneys, and the rema... Erythropoietin Stimulates Production of Proerythroblasts From Hematopoietic Stem Cells. When an animal or person is placed in an... Maturation of Red Blood Cells Requires Vitamin B12 (Cyanocobalamin) and Folic Acid Maturation Failure Anemia Caused by Poor Absorption of Vitamin B12 From the Gastrointestinal Tract—Pernicious Anemia. A common c... Maturation Failure Anemia Caused by Folic Acid (Pteroylglutamic Acid) Deficiency. Folic acid is a normal constituent of green ve... Hemoglobin Formation Iron Metabolism Transport and Storage of Iron. Transport, storage, and metabolism of iron in the body are diagrammed in Figure 33-7 and can be ... Daily Loss of Iron. An average man excretes about 0.6 mg of iron each day, mainly into the feces. Additional quantities of iron ... Absorption of Iron From the Intestinal Tract Regulation of Total Body Iron by Controlling Absorption Rate. When the body becomes saturated with iron so that essentially all ... Destruction of Hemoglobin by Macrophages. When RBCs burst and release their hemoglobin, the hemoglobin is phagocytized almost im... Anemias Blood Loss Anemia. After rapid hemorrhage, the body replaces the fluid portion of the plasma in 1 to 3 days, but this response r... Aplastic Anemia Due to Bone Marrow Dysfunction. Bone marrow aplasia means lack of functioning bone marrow. For example, exposure... Megaloblastic Anemia. Based on the earlier discussions of vitamin B12, folic acid, and intrinsic factor from the stomach mucosa,... Hemolytic Anemia. Different abnormalities of the RBCs, many of which are acquired through hereditary, make the cells fragile, so... Polycythemia Secondary Polycythemia. Whenever the tissues become hypoxic because of too little oxygen in the breathed air, such as at high al... 34 - Resistance of the Body to Infection: I. Leukocytes, Granulocytes, the Monocyte-Macrophage System, and Inflammation Leukocytes (White Blood Cells) Genesis of White Blood Cells Life Span of White Blood Cells Neutrophils and Macrophages Defend Against Infections White Blood Cells Enter the Tissue Spaces by Diapedesis. Neutrophils and monocytes can squeeze through gaps between endothelial ... White Blood Cells Move Through Tissue Spaces by Ameboid Motion. Both neutrophils and macrophages can move through the tissues by... White Blood Cells Are Attracted to Inflamed Tissue Areas by Chemotaxis. Many different chemical substances in the tissues cause ... Phagocytosis Phagocytosis by Neutrophils. The neutrophils entering the tissues are already mature cells that can immediately begin phagocytos... Phagocytosis by Macrophages. Macrophages are the end-stage product of monocytes that enter the tissues from the blood. When act... Once Phagocytized, Most Particles Are Digested by Intracellular Enzymes. Once a foreign particle has been phagocytized, lysosome... Neutrophils and Macrophages Can Kill Bacteria.In addition to the digestion of ingested bacteria in phagosomes, neutrophils and m... Monocyte-Macrophage Cell System (Reticuloendothelial System) Tissue Macrophages in Skin and Subcutaneous Tissues (Histiocytes). The skin is mainly impregnable to infectious agents, except w... Macrophages in Lymph Nodes. Essentially no particulate matter that enters the tissues, such as bacteria, can be absorbed directl... Alveolar Macrophages in Lungs. Another route whereby invading organisms frequently enter the body is through the lungs. Large nu... Macrophages (Kupffer Cells) in Liver Sinusoids. Another route whereby bacteria invade the body is through the gastrointestinal t... Macrophages of Spleen and Bone Marrow. If an invading organism succeeds in entering the general circulation, there are other lin... Inflammation Macrophage and Neutrophil Responses During Inflammation Tissue Macrophages Provide First Line of Defense Against Infection. Within minutes after inflammation begins, the macrophages al... Neutrophil Invasion of the Inflamed Area Is a Second Line of Defense. Within the first hour or so after inflammation begins, lar... Acute Increase in the Number of Neutrophils in Blood—Neutrophilia. Also, within a few hours after the onset of acute severe infl... Second Macrophage Invasion Into the Inflamed Tissue Is a Third Line of Defense. Along with the invasion of neutrophils, monocyte... Increased Production of Granulocytes and Monocytes by Bone Marrow Is a Fourth Line of Defense. The fourth line of defense is gre... Feedback Control of Macrophage and Neutrophil Responses Formation of Pus Eosinophils Basophils Leukopenia Leukemias 35 - Resistance of the Body to Infection: II. Immunity and Allergy Acquired (Adaptive) Immunity T and B Lymphocytes Promote Cell-Mediated and Humoral Immunity. Although most lymphocytes in normal lymphoid tissue look alike... Thymus Gland Preprocesses T Lymphocytes. The T lymphocytes, after origination in the bone marrow, first migrate to the thymus gl... Liver and Bone Marrow Preprocess B Lymphocytes. In humans, B lymphocytes are preprocessed in the liver during midfetal life and ... Millions of Specific Types of Lymphocytes Are Stored in Lymphoid Tissue. Millions of different types of preformed B lymphocytes ... Role of Macrophages in the Activation Process. Aside from the lymphocytes in lymphoid tissue, literally millions of macrophages ... Role of T Cells in Activation of B Lymphocytes. Most antigens activate both T lymphocytes and B lymphocytes at the same time. So... Specific Attributes of The B-Lymphocyte System—Humoral Immunity and Antibodies Antibody Formation by Plasma Cells. Before exposure to a specific antigen, the clones of B lymphocytes remain dormant in the lym... Formation of Memory Cells Enhances Antibody Response to Subsequent Antigen Exposure. A few of the lymphoblasts formed by activat... Generation of Lifelong Immunity by Plasma Cells. When naïve B lymphocytes encounter their associated antigens, become activated,... Nature of Antibodies Specificity of Antibodies. Each antibody is specific for a particular antigen; this characteristic is a result of the unique str... Five General Classes of Antibodies. There are five general classes of antibodies, respectively named IgM, IgG, IgA, IgD, and IgE... Mechanisms of Action of Antibodies Direct Action of Antibodies on Invading Agents. Figure 35-5 shows antibodies (designated by the red Y-shaped bars) reacting wi... Classical Pathway. The classical pathway is initiated by an antigen-antibody reaction. That is, when an antibody binds with an ... Special Attributes of T-Lymphocyte System—Activated T Cells and Cell-Mediated Immunity Release of Activated T Cells From Lymphoid Tissue and Formation of Memory Cells. On exposure to the proper antigen, as presented... Antigen-Presenting Cells, Major Histocompatibility Complex Proteins, and Antigen Receptors on T Lymphocytes. T-cell responses ... Different Types of T Cells and Their Functions T-Helper Cells Are the Most NumerousT Cells Specific Regulatory Functions of Lymphokines. In the absence of the lymphokines from the T-helper cells, the remainder of the i... Stimulation of Growth and Proliferation of Cytotoxic T Cells and Regulatory T Cells. In the absence of T-helper cells, the clon... Stimulation of B-Cell Growth and Differentiation to Form Plasma Cells and Antibodies. The direct actions of antigens to cause B... Activation of the Macrophage System. The lymphokines also affect the macrophages. First, they slow or stop the migration of the ... Feedback Stimulatory Effect on T-Helper Cells. Some of the lymphokines, especially interleukin-2, have a direct positive feedb... Cytotoxic T Cells Are Killer Cells Regulatory T Cells Most Tolerance Results From Clone Selection During Preprocessing. Most tolerance is believed to develop during the preprocessing... Failure of the Tolerance Mechanism Causes Autoimmune Diseases. Sometimes, people lose immune tolerance of their own tissues. Thi... Passive Immunity Allergy and Hypersensitivity Anaphylaxis—Widespread Allergic Reaction. When a specific allergen is injected directly into the circulation, the allergen can r... Urticaria—Localized Anaphylactoid Reactions. Urticaria results from antigen entering specific skin areas and causing localized ... Hay Fever. In hay fever, the allergen-reagin reaction occurs in the nose. Histamine released in response to the reaction causes... Asthma. Asthma often occurs in the hypersensitive allergic person. In these individuals, the allergen-reagin reaction occurs in... 36 - Blood Types; Transfusion; and Tissue and Organ Transplantation Antigenicity Causes Immune Reactions of Blood O-A-B Blood Types A and B Antigens—Agglutinogens Agglutinins Blood Typing Rh Blood Types Rh Immune Response Transfusion Reactions Resulting From Mismatched Blood Types Transplantation of Tissues and Organs 37 - Hemostasis and Blood Coagulation HEMOSTASIS EVENTS VASCULAR CONSTRICTION FORMATION OF THE PLATELET PLUG Physical and Chemical Characteristics Mechanism of Platelet Plug Formation MECHANISM OF BLOOD COAGULATION GENERAL MECHANISM CONVERSION OF FIBRINOGEN TO FIBRIN—FORMATION OF THE CLOT Extrinsic Pathway for Initiating Clotting Intrinsic Pathway for Initiating Clotting Role of Calcium Ions in the Intrinsic and Extrinsic Pathways Interaction Between Extrinsic and Intrinsic Pathways—Summary of Blood-Clotting Initiation PLASMIN CAUSES LYSIS OF BLOOD CLOTS CONDITIONS THAT CAUSE EXCESSIVE BLEEDING IN HUMANS HEMOPHILIA THROMBOCYTOPENIA THROMBOEMBOLIC CONDITIONS ANTICOAGULANTS FOR CLINICAL USE COUMARINS AS ANTICOAGULANTS BLOOD COAGULATION TESTS BLEEDING TIME CLOTTING TIME 38 - Pulmonary Ventilation 39 - Pulmonary Circulation, Pulmonary Edema, and Pleural Fluid 40 - Principles of Gas Exchange; Diffusion of Oxygen and Carbon Dioxide Through the Respiratory Membrane Compositions of Alveolar Air and Atmospheric Air are Different Air Is Humidified in the Respiratory Passages Alveolar Air Is Slowly Renewed by Atmospheric Air Slow Replacement of Alveolar Air Helps Stabilize Respiratory Control. The slow replacement of alveolar air is of particular impo... Oxygen Concentration and Partial Pressure in Alveoli CO2 Concentration and Partial Pressure in Alveoli Respiratory Membrane. Figure 40-9 shows the ultrastructure of the respiratory membrane drawn in cross section on the left and a... Factors Affecting Rate of Gas Diffusion Through the Respiratory Membrane Diffusing Capacity of the Respiratory Membrane Diffusing Capacity for Oxygen. In the average young man, the diffusing capacity for O2 under resting conditions averages 21 ml/m... Increased Oxygen Diffusing Capacity During Exercise. During strenuous exercise or other conditions that greatly increase pulmona... Diffusing Capacity for Carbon Dioxide. The diffusing capacity for CO2 has never been measured because CO2 diffuses through the r... 41 - Transport of Oxygen and Carbon Dioxide in Blood and Tissue Fluids Uptake of Oxygen by the Pulmonary Blood During Exercise. During strenuous exercise, a person’s body may require as much as 20 ti... Increasing Blood Flow Raises Interstitial Fluid Po2. If the blood flow through a particular tissue is increased, greater quantit... Reversible Combination of O2 With Hemoglobin Oxygen-Hemoglobin Dissociation Curve. Figure 41-8 shows the O2-hemoglobin dissociation curve, which demonstrates a progressive... Maximum Amount of Oxygen That Can Combine With the Hemoglobin of the Blood. The blood of a normal person contains about 15 grams... Amount of Oxygen Released From Hemoglobin When Systemic Arterial Blood Flows Through Tissues. The total quantity of O2 bound wit... Transport of Oxygen Is Markedly Increased During Strenuous Exercise. During heavy exercise, the muscle cells use O2 at a rapid r... Utilization Coefficient. The percentage of the blood that gives up its O2 as it passes through the tissue capillaries is called ... Hemoglobin “Buffers” Tissue Po2 Hemoglobin Helps Maintain Nearly Constant Po2 in the Tissues. Under basal conditions, the tissues require about 5 ml of O2 from ... When Atmospheric Oxygen Concentration Changes Markedly, the Buffer Effect of Hemoglobin Still Maintains Almost Constant Tissue P... Factors That Shift the Oxygen-Hemoglobin Dissociation Curve—Their Importance for Oxygen Transport Increased Delivery of Oxygen to Tissues When CO2 and H+ Shift the Oxygen-Hemoglobin Dissociation Curve—the Bohr Effect Effect of BPG to Cause Rightward Shift of the Oxygen-Hemoglobin Dissociation Curve Rightward Shift of the Oxygen-Hemoglobin Dissociation Curve During Exercise Metabolic Use of Oxygen by Cells Effect of Intracellular Po2 on Oxygen Usage Rate. Only a minute level of O2 pressure is required in the cells for normal intrace... Effect of Diffusion Distance From the Capillary to the Cell on Oxygen Usage. Tissue cells are seldom more than 50 micrometers aw... Effect of Blood Flow on Metabolic Use of Oxygen. The total amount of O2 available each minute for use in any given tissue is det... Transport of Co2 in Blood Transport of CO2 in a Dissolved State Carbon Dioxide Dissociation Curve When Oxygen Binds With Hemoglobin, CO2 Is Released (the Haldane Effect) to Increase CO2 Transport Respiratory Exchange Ratio 42 - Regulation of Respiration Respiratory Center Rhythmical Inspiratory Discharges From the Dorsal Respiratory Group. The basic rhythm of respiration is generated mainly in the ... Chemical Control of Respiration Direct Control of Respiratory Center Activity by Co2 and H+ Chemosensitive Area of the Respiratory Center Beneath the Medulla’s Ventral Surface. We have mainly discussed three areas of the... Excitation of the Chemosensitive Neurons by H+ Is Likely the Primary Stimulus. The sensor neurons in the chemosensitive area are... CO2 Indirectly Stimulates the Chemosensitive Neurons. Although CO2 has little direct effect in stimulating the neurons in the ch... Attenuated Stimulatory Effect of CO2 After the First 1 to 2 Days. Excitation of the respiratory center by CO2 is great the first... Quantitative Effects of Blood Pco2 and H+ Concentration on Alveolar Ventilation. Figure 42-3 shows quantitatively the approxima... Changes in O2 Have Little Direct Effect on Control of the Respiratory Center. Changes in O2 concentration have virtually no dire... Peripheral Chemoreceptor System—Role of Oxygen in Respiratory Control Decreased Arterial Oxygen Stimulates the Chemoreceptors. When the oxygen concentration in the arterial blood falls below normal,... Basic Mechanism of Stimulation of the Chemoreceptors by O2 Deficiency. The exact means whereby low Po2 excites the nerve endings... Increased CO2 and H+ Concentration Stimulates the Chemoreceptors. An increase in CO2 or H+ concentration also excites the chemor... Effect of Low Arterial Po2 to Stimulate Alveolar Ventilation When Arterial CO2 and H+ Concentrations Remain Normal Chronic Breathing of Low O2 Stimulates Respiration Even More—The Phenomenon of “Acclimatization” Composite Effects of Pco2, pH, and Po2 on Alveolar Ventilation Regulation of Respiration During Exercise Interrelationship Between Chemical and Nervous Factors in Controlling Respiration During Exercise. When a person exercises, dire... 43 - Respiratory Insufficiency—Pathophysiology, Diagnosis, Oxygen Therapy Useful Methods for Studying Respiratory Abnormalities Study of Blood Gases and Blood ph Determination of Blood pH. Blood pH is measured using a glass pH electrode of the type commonly used in chemical laboratories. H... Determination of Blood CO2. A glass electrode pH meter can also be used to determine blood CO2. When a weak solution of sodium b... Determination of Blood Po2. The concentration of O2 in a fluid can be measured by a technique called polarography. Electric curr... Abnormalities of the Maximum Expiratory Flow-Volume Curve. Figure 43-2 shows the normal maximum expiratory flow-volume curve,... Chronic Pulmonary Emphysema Atelectasis—Collapse of the Alveoli Airway Obstruction Causes Lung Collapse. The airway obstruction type of atelectasis usually results from the following: (1) bloc... Lack of “Surfactant” as a Cause of Lung Collapse. The secretion and function of surfactant in the alveoli were discussed in Chap... Tuberculosis Hypoxia and Oxygen Therapy Inadequate Tissue Capability to Use Oxygen. The classic cause of inability of the tissues to use O2 is cyanide poisoning, in whi... Cyanosis Hypercapnia—Excess Carbon Dioxide in the Body Fluids Dyspnea Artificial Respiration Resuscitator. Many types of respiratory resuscitators are available, and each has its own characteristic principles of operation... Tank Respirator (the “Iron Lung”). Figure 43-9B shows the tank respirator with a patient’s body inside the tank and the head pr... Effect of the Resuscitator and the Tank Respirator on Venous Return. When air is forced into the lungs under positive pressure b... 44 - Aviation, High Altitude, and Space Physiology Alveolar Po2 at Different Elevations Carbon Dioxide and Water Vapor Decrease the Alveolar Oxygen. Even at high altitudes, carbon dioxide (CO2) is continually excrete... Alveolar Po2 at Different Altitudes. The fifth column of Table 44-1 shows the approximate Po2 values in the alveoli at differen... Saturation of Hemoglobin With Oxygen at Different Altitudes. Figure 44-1 shows arterial blood O2 saturation at different altitu... The “Ceiling” When Breathing Air and When Breathing Oxygen in an Unpressurized Airplane. When comparing the two arterial blood O... Acute Effects of Hypoxia Acclimatization to Low Po2 Increased Pulmonary Ventilation—Role of Arterial Chemoreceptors. Immediate exposure to low Po2 stimulates the arterial chemorece... Increase in Red Blood Cells and Hemoglobin Concentration During Acclimatization. As discussed in Chapter 33, hypoxia is a major ... Increased Diffusing Capacity After Acclimatization. The normal diffusing capacity for O2 through the pulmonary membrane is about... Peripheral Circulatory System Changes During Acclimatization—Increased Tissue Capillarity. The cardiac output often increases as... Cellular Acclimatization. In animals native to altitudes of 13,000 to 17,000 feet, cell mitochondria and cellular oxidative enzy... Chronic Mountain Sickness 45 - Physiology of Deep-Sea Diving and Other Hyperbaric Conditions Relationship of Pressure to Sea Depth. A column of seawater 33 feet (10.1 meters) deep exerts the same pressure at its bottom as... Effect of High Partial Pressures of Individual Gases on the Body Oxygen Toxicity at High Pressures Effect of Very High Po2 on Blood Oxygen Transport. When the Po2 in the blood rises above 100 mm Hg, the amount of O2 dissolved i... Effect of High Alveolar Po2 on Tissue Po2. Let us assume that the Po2 in the lungs is about 3000 mm Hg (4 atm pressure). Referri... Acute Oxygen Poisoning. The extremely high tissue Po2 that occurs when O2 is breathed at a very high alveolar O2 pressure can be... Excessive Intracellular Oxidation as a Cause of Nervous System Oxygen Toxicity—Oxidizing Free Radicals. Molecular O2 has little ... Chronic Oxygen Poisoning Causes Pulmonary Disability. A person can be exposed to only 1 atm pressure of O2 almost indefinitely w... Carbon Dioxide Toxicity at Great Depths in the Sea Decompression of the Diver After Excess Exposure to High Pressure Symptoms of Decompression Sickness (“Bends”). The symptoms of decompression sickness are caused by gas bubbles blocking many blo... Nitrogen Elimination From the Body; Decompression Tables. If a diver is brought to the surface slowly, enough of the dissolved n... Tank Decompression and Treatment of Decompression Sickness. Another procedure widely used for decompression of professional dive... Self-Contained Underwater Breathing Apparatus (Scuba) Diving 46 - Organization of the Nervous System, Basic Functions of Synapses, and Neurotransmitters Central Nervous System Neuron: The Basic Functional Unit Storage of Information—Memory Major Levels of Central Nervous System Function Spinal Cord Level Lower Brain or Subcortical Level Higher Brain or Cortical Level Comparison of the Nervous System to A Computer Central Nervous System Synapses “One-Way” Conduction at Chemical Synapses. Chemical synapses have one exceedingly important characteristic that makes them high... Transmitter Release From Presynaptic Terminals—Role of Calcium Ions Transmitter Actions on Postsynaptic Neurons—Function of Receptor Proteins Ion Channels. The ion channels in the postsynaptic neuronal membrane are usually of two types: (1) cation channels, which usuall... “Second Messenger” System in the Postsynaptic Neuron. Many functions of the nervous system—for example, the process of memory—re... Excitatory or Inhibitory Receptors in the Postsynaptic Membrane Excitation Inhibition Small-Molecule, Rapidly Acting Transmitters Recycling of Small-Molecule Types of Vesicles. Vesicles that store and release small-molecule transmitters are continually rec... Characteristics of Some Important Small-Molecule Transmitters. Acetylcholine is secreted by neurons in many areas of the nervou... Neuropeptides Neuropeptide and Small-Molecule Transmitters May Coexist in the Same Neurons. Slowly acting neuropeptide transmitters and rapid... Resting Membrane Potential of the Neuronal Soma. Figure 46-9 shows the soma of a spinal motor neuron, indicating a resting memb... Concentration Differences of Ions Across the Neuronal Somal Membrane. Figure 46-9 also shows the concentration differences acro... Uniform Distribution of Electrical Potential Inside the Neuronal Soma. The interior of the neuronal soma contains a highly condu... Effect of Synaptic Excitation on the Postsynaptic Membrane—Excitatory Postsynaptic Potential. Figure 46-10A shows the resting n... Generation of Action Potentials in the Initial Segment of the Axon Leaving the Neuron—Threshold for Excitation. When the EPSP ri... Electrical Events During Neuronal Inhibition Effect of Inhibitory Synapses on the Postsynaptic Membrane—Inhibitory Postsynaptic Potential. The inhibitory synapses mainly ope... Presynaptic Inhibition Time Course of Postsynaptic Potentials “Spatial Summation” in Neurons—Threshold for Firing “Temporal Summation” Caused by Successive Discharges of a Presynaptic Terminal Simultaneous Summation of Inhibitory and Excitatory Postsynaptic Potentials. If an IPSP tends to decrease the membrane potential... Facilitation of Neurons Special Functions of Dendrites for Exciting Neurons Large Spatial Field of Excitation of Dendrites. The dendrites of the anterior motor neurons often extend 500 to 1000 micrometers... Most Dendrites Cannot Transmit Action Potentials—But They Can Transmit Signals Within the Same Neuron by Electrotonic Conduction... Decrement of Electrotonic Conduction in the Dendrites—Greater Excitatory (or Inhibitory) Effect by Synapses Located Near the Som... Summation of Excitation and Inhibition in Dendrites. The uppermost dendrite of Figure 46-12 is shown to be stimulated by both e... Excitation State of the Neuron and Rate of Firing “Excitatory State” Is the Summated Degree of Excitatory Drive to the Neuron. If there is a higher degree of excitation than inhi... Fatigue of Synaptic Transmission. When excitatory synapses are repetitively stimulated at a rapid rate, the number of discharges... Effect of Acidosis or Alkalosis on Synaptic Transmission. Most neurons are highly responsive to changes in pH of the surrounding... Effect of Hypoxia on Synaptic Transmission. Neuronal excitability is also highly dependent on an adequate supply of oxygen. Cess... Effect of Drugs on Synaptic Transmission. Many drugs are known to increase the excitability of neurons, and others are known to ... Synaptic Delay. During transmission of a neuronal signal from a presynaptic neuron to a postsynaptic neuron, a certain amount of... 47 - Sensory Receptors, Neuronal Circuits for Processing Information Types of Sensory Receptors and the Stimuli they Detect Differential Sensitivity of Receptors Modality of Sensation—The “Labeled Line” Principle Local Electrical Currents at Nerve Endings—Receptor Potentials Mechanisms of Receptor Potentials. Different receptors can be excited in one of several ways to cause receptor potentials: (1) b... Maximum Receptor Potential Amplitude. The maximum amplitude of most sensory receptor potentials is about 100 mV, but this level ... Relation of the Receptor Potential to Action Potentials. When the receptor potential rises above the threshold for eliciting act... Receptor Potential of the Pacinian Corpuscle—an Example of Receptor Function Relation Between Stimulus Intensity and the Receptor Potential. Figure 47-4 shows the changing amplitude of the receptor potent... Adaptation of Receptors Mechanisms by Which Receptors Adapt. The mechanism of receptor adaptation is different for each type of receptor in much the sam... Slowly Adapting Receptors Detect Continuous Stimulus Strength—the “Tonic” Receptors. Slowly adapting receptors continue to trans... Rapidly Adapting Receptors Detect Change in Stimulus Strength—the “Rate Receptors,” “Movement Receptors,” or “Phasic Receptors.”... Predictive Function of the Rate Receptors. If the rate at which some change in the body’s status is taking place is known, the s... Signal Intensity Transmission in Nerve Tracts—Spatial and Temporal Summation Spatial Summation. Figure 47-7 shows the phenomenon of spatial summation, whereby increasing signal strength is transmitted by ... Transmission and Processing of Signals in Neuronal Pools Relaying of Signals Through Neuronal Pools Organization of Neurons for Relaying Signals. Figure 47-9 is a schematic diagram of several neurons in a neuronal pool, showin... Threshold and Subthreshold Stimuli—Excitation or Facilitation. As discussed in Chapter 46, discharge of a single excitatory pres... Inhibition of a Neuronal Pool. Some incoming fibers inhibit neurons, rather than exciting them. This mechanism is the opposite o... Divergence of Signals Passing Through Neuronal Pools Convergence of Signals Neuronal Circuit With Both Excitatory and Inhibitory Output Signals Synaptic Afterdischarge. When excitatory synapses discharge on the surfaces of dendrites or soma of a neuron, a postsynaptic ele... Reverberatory (Oscillatory) Circuit as a Cause of Signal Prolongation. One of the most important of all circuits in the entire n... Signal Prolongation Characteristics of a Reverberatory Circuit. Figure 47-15 shows output signals from a typical reverberatory ... Continuous Signal Output From Some Neuronal Circuits Continuous Discharge Caused by Intrinsic Neuronal Excitability. Neurons, like other excitable tissues, discharge repetitively if... Continuous Signals Emitted From Reverberating Circuits as a Means for Transmitting Information. A reverberating circuit that doe... Rhythmical Signal Output Instability and Stability of Neuronal Circuits Automatic Short-Term Adjustment of Pathway Sensitivity by the Fatigue Mechanism. Those neuronal pathways that are overused usua... 48 - Somatic Sensations: I. General Organization, Tactile and Position Senses Classification of Somatic Senses Detection and Transmission of Tactile Sensations Interrelations Among the Tactile Sensations of Touch, Pressure, and Vibration. Although touch, pressure, and vibration are frequ... Tactile Receptors. There are at least six entirely different types of tactile receptors, but many more similar to these also exi... Transmission of Tactile Signals in Peripheral Nerve Fibers. Almost all specialized sensory receptors, such as Meissner’s corpusc... Detection of Vibration. All tactile receptors are involved in detection of vibration, although different receptors detect differ... Detection of Tickle and Itch by Mechanoreceptive Free Nerve Endings. Neurophysiological studies have demonstrated the existence ... Sensory Pathways for Transmitting Somatic Signals Into the Central Nervous System Anatomy of the Dorsal Column–Medial Lemniscal System Spatial Orientation of the Nerve Fibers in the Dorsal Column–Medial Lemniscal System Somatosensory Cortex Somatosensory Areas I and II. Figure 48-6 shows two separate sensory areas in the anterior parietal lobe called somatosensory a... Spatial Orientation of Signals From Different Parts of the Body in Somatosensory Area I. Somatosensory area I lies immediately b... Layers of the Somatosensory Cortex and Their Function The Sensory Cortex Is Organized in Vertical Columns of Neurons; Each Column Detects a Different Sensory Spot on the Body With a ... Functions of Somatosensory Area I Somatosensory Association Areas Characteristics of Dorsal Column–Medial Lemniscal Signal Transmission and Analysis Basic Neuronal Circuit in the Dorsal Column–Medial Lemniscal System. The lower part of Figure 48-9 shows the basic organization... Two-Point Discrimination. A method frequently used to test tactile discrimination is to determine a person’s so-called “two-p... Effect of Lateral Inhibition to Increase the Degree of Contrast in the Perceived Spatial Pattern. As noted in Chapter 47, virtua... Transmission of Rapidly Changing and Repetitive Sensations. The dorsal column system is also of particular importance in apprisi... Vibratory Sensation. Vibratory signals are rapidly repetitive and can be detected as vibration up to 700 cycles/sec. The higher ... Position Senses Position Sensory Receptors. Knowledge of position, both static and dynamic, depends on knowing the degrees of angulation of all ... Processing of Position Sense Information in the Dorsal Column–Medial Lemniscal Pathway. Referring to Figure 48-12, one sees t... Transmission of Sensory Signals in the Anterolateral Pathway 49 - Somatic Sensations: II. Pain, Headache, and Thermal Sensations Fast Pain and Slow Pain and Their Qualities Pain Receptors Are Free Nerve Endings. The pain receptors in the skin and other tissues are all free nerve endings. They are wid... Mechanical, Thermal, and Chemical Stimuli Excite Pain Receptors. Pain can be elicited by multiple types of stimuli, classified a... Nonadapting Nature of Pain Receptors. In contrast to most other sensory receptors of the body, pain receptors adapt very little ... Rate of Tissue Damage as a Stimulus for Pain. The average person begins to perceive pain when the skin is heated above 45°C, as ... Special Importance of Chemical Pain Stimuli During Tissue Damage. Extracts from damaged tissue cause intense pain when injected ... Tissue Ischemia as a Cause of Pain. When blood flow to a tissue is blocked, the tissue often becomes very painful within a few m... Muscle Spasm as a Cause of Pain. Muscle spasm is also a common cause of pain and is the basis of many clinical pain syndromes. T... Dual Pathways for Transmission of Pain Signals Into the Central Nervous System Neospinothalamic Tract for Fast Pain Termination of the Neospinothalamic Tract in the Brain Stem and Thalamus. A few fibers of the neospinothalamic tract terminate i... The Nervous System Can Localize Fast Pain in the Body. The fast-sharp type of pain can be localized much more exactly in the di... Glutamate, the Probable Neurotransmitter of the Type Aδ Fast Pain Fibers. It is believed that glutamate is the neurotransmitter ... Paleospinothalamic Pathway for Transmitting Slow-Chronic Pain Substance P, the Probable Slow-Chronic Neurotransmitter of Type C Nerve Endings. Type C pain fiber terminals entering the spina... Projection of Paleospinothalamic Pathway (Slow-Chronic Pain Signals) Into the Brain Stem and Thalamus. The slow-chronic paleos... Poor Capability of the Nervous System to Localize Precisely the Source of Pain Transmitted in the Slow-Chronic Pathway. Localiz... Function of the Reticular Formation, Thalamus, and Cerebral Cortex in the Appreciation of Pain. Complete removal of the somatic ... Special Capability of Pain Signals to Arouse Overall Brain Excitability. Electrical stimulation in the reticular areas of the br... Surgical Interruption of Pain Pathways. When a person has severe and intractable pain (sometimes resulting from rapidly spreadin... Pain Suppression (Analgesia) System in the Brain and Spinal Cord The Brain’s Opiate System—Endorphins and Enkephalins Referred Pain Visceral Pain Localization of Referred Pain Transmitted via Visceral Pathways. When visceral pain is referred to the surface of the body, the ... Thermal Sensations Thermal Receptors and Their Excitation Stimulation of Thermal Receptors—Sensations of Cold, Cool, Indifferent, Warm, and Hot. Figure 49-10 shows the effects of differ... Stimulatory Effects of Rising and Falling Temperature—Adaptation of Thermal Receptors. When a cold receptor is suddenly subjecte... Spatial Summation of Thermal Sensations. Because the number of cold or warmth endings in any one surface area of the body is sli... 50 - The Eye: I. Optics of Vision Physical Principles of Optics Optics of the Eye Consideration of All Refractive Surfaces of the Eye as a Single Lens—The “Reduced” Eye. If all the refractive surfaces of the ey... Mechanism of “accommodation” Accommodation Is Controlled by Parasympathetic Nerves. Ciliary muscle is controlled almost entirely by parasympathetic nerve sig... Presbyopia—Loss of Accommodation by the Lens. As a person grows older, the lens grows larger and thicker and becomes far less el... Pupillary Diameter Visual Acuity Clinical Method for Stating Visual Acuity. The chart for testing eyes usually consists of letters of different sizes placed 20 f... Determination of Distance by Sizes of Retinal Images of Known Objects. If one knows that a person being viewed is 6 feet tall, o... Determination of Distance by Moving Parallax. Another important means whereby the eyes determine distance is that of moving para... Determination of Distance by Stereopsis—Binocular Vision. Another method whereby one perceives parallax is that of binocular vis... Fluid System of the Eye—Intraocular Fluid Intraocular Pressure 51 - The Eye: II. Receptor and Neural Function of the Retina Anatomy and Function of the Structural Elements of the Retina The Retina Is Composed of Ten Layers or Boundaries. Figure 51-1 shows the functional components of the retina, which are arrang... Foveal Region of the Retina and Its Importance in Acute Vision. The fovea is a minute area in the center of the retina, shown in... Rods and Cones Are Essential Components of Photoreceptors. Figure 51-3 is a diagrammatic representation of the essential compon... Pigment Layer of the Retina. The black pigment melanin in the pigment layer prevents light reflection throughout the globe of th... Photochemistry of Vision Rhodopsin-Retinal Visual Cycle and Excitation of the Rods Rhodopsin and Its Decomposition by Light Energy. The outer segment of the rod that projects into the pigment layer of the retina... Re-Formation of Rhodopsin. The first stage in re-formation of rhodopsin, as shown in Figure 51-5, is to reconvert the all-tr... Role of Vitamin A for Formation of Rhodopsin. Note in Figure 51-5 that there is a second chemical route whereby all-trans reti... Duration of the Receptor Potential, and Logarithmic Relation of the Receptor Potential to Light Intensity. When a sudden pulse o... Mechanism Whereby Rhodopsin Decomposition Decreases Membrane Sodium Conductance—The Excitation “Cascade.” Under optimal conditio... Photochemistry of Color Vision by the Cones Value of Light and Dark Adaptation in Vision. Between the limits of maximal dark adaptation and maximal light adaptation, the ey... Color Vision Spectral Sensitivities of the Three Types of Cones. On the basis of color vision tests, the spectral sensitivities of the three ... Interpretation of Color in the Nervous System. In Figure 51-10, one can see that an orange monochromatic light with a wavelengt... Perception of White Light. About equal stimulation of all the red, green, and blue cones gives one the sensation of seeing white... Neural Function of the Retina The Visual Pathway From the Cones to the Ganglion Cells Functions Differently From the Rod Pathway. As is true for many of our o... Neurotransmitters Released by Retinal Neurons. Not all the neurotransmitter chemical substances used for synaptic transmission i... Transmission of Most Signals Occurs in the Retinal Neurons by Electrotonic Conduction, Not by Action Potentials. The only retina... Lateral Inhibition to Enhance Visual Contrast—Function of the Horizontal Cells Depolarizing and Hyperpolarizing Bipolar Cells Amacrine Cells and Their Functions P and M Cells. In primates, a different classification of retinal ganglion cells is used, and as many as 20 types of retinal gan... Excitation of the Ganglion Cells Spontaneous, Continuous Action Potentials in the Ganglion Cells. It is from the ganglion cells that the long fibers of the optic... Transmission of Signals Depicting Contrasts in the Visual Scene—The Role of Lateral Inhibition Transmission of Color Signals by the Ganglion Cells 52 - The Eye: III. Central Neurophysiology of Vision Visual Pathways Organization and Function of the Visual Cortex Primary Visual Cortex. The primary visual cortex (see Figure 52-2) lies in the calcarine fissure area, extending forward from t... The Primary Visual Cortex has six Major Layers Vertical Neuronal Columns in the Visual Cortex. The visual cortex is organized structurally into several million vertical column... “Color Blobs” in the Visual Cortex. Interspersed among the primary visual columns, as well as among the columns of some of the s... Interaction of Visual Signals From the Two Separate Eyes. Recall that visual signals from the two separate eyes are relayed thro... Two Major Pathways for Analysis of Visual Information: (1) The Fast “Position” and “Motion” Pathway and (2) the Accurate Color P... Analysis of Contrasts in Visual Images. If a person looks at a blank wall, only a few neurons in the primary visual cortex will ... Visual Cortex Also Detects Orientation of Lines and Borders—“Simple” Cells. The visual cortex detects not only the existence of ... “Complex” Cells Detect Line Orientation When a Line Is Displaced Laterally or Vertically in the Visual Field. As the visual sign... Detection of Lines of Specific Lengths, Angles, or Other Shapes. Some neurons in the outer layers of the primary visual columns,... Detection of Color Eye Movements and Their Control Muscular Control of Eye Movements. The eye movements are controlled by three pairs of muscles, shown in Figure 52-7: (1) the me... Fixation Movements of the Eyes Mechanism of Involuntary Locking Fixation—Role of the Superior Colliculi. The involuntary locking type of fixation discussed in ... Saccadic Movement of the Eyes—A Mechanism of Successive Fixation Points. When a visual scene is moving continually before the ey... Saccadic Movements During Reading. During the process of reading, a person usually makes several saccadic movements of the eyes ... Fixation on Moving Objects—“Pursuit Movement.” The eyes can also remain fixed on a moving object, which is called pursuit moveme... Superior Colliculi Are Mainly Responsible for Turning the Eyes and Head Toward a Visual Disturbance. Even after the visual corte... Neural Mechanism of Stereopsis for Judging Distances of Visual Objects Autonomic Nerves to the Eyes Control of Pupillary Diameter 53 - The Sense of Hearing 54 - The Chemical Senses—Taste and Smell Sense of Taste Primary Taste Sensations Sour Taste. The sour taste is caused by acids—that is, by the hydrogen ion concentration—and the intensity of this taste sensati... Salty Taste. The salty taste is elicited by ionized salts, mainly by the sodium ion concentration. The quality of the taste vari... Sweet Taste. The sweet taste is not caused by any single class of chemicals. Some of the types of chemicals that cause this tast... Bitter Taste. The bitter taste, like the sweet taste, is not caused by any single type of chemical agent. Here again, the substa... Umami Taste. Umami, a Japanese word meaning “delicious,” designates a pleasant taste sensation that is qualitatively different f... Threshold for Taste Taste Buds and Their Function Location of the Taste Buds. The taste buds are found on three types of papillae of the tongue, as follows (see Figure 54-1A): (... Specificity of Taste Buds for a Primary Taste Stimulus. Microelectrode studies from single taste buds show that each taste bud ... Generation of Nerve Impulses by the Taste Bud. On first application of the taste stimulus, the rate of discharge of the nerve fi... Taste Reflexes Are Integrated in the Brain Stem. From the tractus solitarius, many taste signals are transmitted within the brai... Rapid Adaptation of Taste. Everyone is familiar with the fact that taste sensations adapt rapidly, often almost completely, with... Sense of Smell Olfactory Membrane Stimulation of the Olfactory Cells Mechanism of Excitation of the Olfactory Cells. The portion of each olfactory cell that responds to the olfactory chemical stimu... Membrane Potentials and Action Potentials in Olfactory Cells. The membrane potential inside unstimulated olfactory cells, as me... Rapid Adaptation of Olfactory Sensations. The olfactory receptors adapt about 50% in the first second or so after stimulation. T... Search for the Primary Sensations of Smell Affective Nature of Smell. Smell, even more so than taste, has the affective quality of either pleasantness or unpleasantness, a... Threshold for Smell. One of the principal characteristics of smell is the minute quantity of stimulating agent in the air that c... Gradations of Smell Intensities. Although the threshold concentrations of substances that evoke smell are extremely slight, for ... Transmission of Olfactory Signals Into the Olfactory Bulb. The olfactory bulb is shown in Figure 54-5. The olfactory nerve fibe... Primitive and Newer Olfactory Pathways Into the Central Nervous System The Primitive Olfactory System—The Medial Olfactory Area. The medial olfactory area consists of a group of nuclei located in th... The Less Old Olfactory System—The Lateral Olfactory Area. The lateral olfactory area is composed mainly of the prepyriform and ... The Newer Pathway. A newer olfactory pathway that passes through the thalamus, passing to the dorsomedial thalamic nucleus and t... Summary. Thus, there appear to be a primitive olfactory system that subserves the basic olfactory reflexes, a less old system th... Centrifugal Control of Activity in the Olfactory Bulb by the Central Nervous System. Many nerve fibers that originate in the olf... 55 - Spinal Cord Motor Functions; the Cord Reflexes Organization of the Spinal Cord for Motor Functions Anterior Motor Neurons. Located in each segment of the anterior horns of the cord gray matter are several thousand neurons that ... Alpha Motor Neurons. The alpha motor neurons give rise to large type A alpha (Aα) motor nerve fibers, averaging 14 micrometers i... Gamma Motor Neurons. Along with the alpha motor neurons, which excite contraction of the skeletal muscle fibers, about one-half ... Interneurons. Interneurons are present in all areas of the cord gray matter—in the dorsal horns, the anterior horns, and the int... Muscle Sensory Receptors—Muscle Spindles and Golgi Tendon Organs—and Their Roles in Muscle Control Receptor Function of the Muscle Spindle Structure and Motor Innervation of the Muscle Spindle. The organization of the muscle spindle is shown in Figure 55-3. Each sp... Sensory Innervation of the Muscle Spindle. The receptor portion of the muscle spindle is its central portion. As shown in Figure... Primary Ending. In the center of the receptor area, a large sensory nerve fiber encircles the central portion of each intrafusal... Secondary Ending. Usually one but sometimes two smaller sensory nerve fibers—type II fibers with an average diameter of 8 microm... Division of the Intrafusal Fibers Into Nuclear Bag and Nuclear Chain Fibers—Dynamic and Static Responses of the Muscle Spindle. ... The Primary and the Secondary Endings Both Respond to the Length of the Receptor—“Static” Response. When the receptor portion of... The Primary Ending (but Not the Secondary Ending) Responds to Rate of Change of Receptor Length—“Dynamic” Response. When the len... Control of Intensity of the Static and Dynamic Responses by the Gamma Motor Nerves. The gamma motor nerves to the muscle spindl... Continuous Discharge of the Muscle Spindles Under Normal Conditions. Normally, when there is some degree of gamma nerve excitati... Muscle Stretch Reflex Neuronal Circuitry of the Stretch Reflex. Figure 55-5 demonstrates the basic circuit of the muscle spindle stretch reflex, show... Dynamic Stretch Reflex and Static Stretch Reflexes. The stretch reflex can be divided into two components: the dynamic stretch r... “Damping” Function of the Dynamic and Static Stretch Reflexes in Smoothing Muscle Contraction. An especially important function ... Brain Areas for Control of the Gamma Motor System The Muscle Spindle System Stabilizes Body Position During Tense Action. One of the most important functions of the muscle spindl... Golgi Tendon Reflex Golgi Tendon Organ Helps Control Muscle Tension. The Golgi tendon organ, shown in Figure 55-8, is an encapsulated sensory recep... Transmission of Impulses From the Tendon Organ Into the Central Nervous System. Signals from the tendon organ are transmitted th... The Tendon Reflex Prevents Excessive Tension on the Muscle. When the Golgi tendon organs of a muscle tendon are stimulated by in... Possible Role of the Tendon Reflex to Equalize Contractile Force Among the Muscle Fibers. Another likely function of the Golgi ... Function of the Muscle Spindles and Golgi Tendon Organs in Motor Control by Higher Levels of the Brain Flexor Reflex and the Withdrawal Reflexes Neuronal Mechanism of the Flexor Reflex. The left-hand portion of Figure 55-9 shows the neuronal pathways for the flexor refle... Crossed Extensor Reflex Reciprocal Inhibition and Reciprocal Innervation Postural and Locomotive Reflexes of the Cord Positive Supportive Reaction. Pressure on the footpad of a decerebrate animal causes the limb to extend against the pressure app... Cord “Righting” Reflexes. When a spinal animal is laid on its side, it will make uncoordinated movements to try to raise itself ... Stepping and Walking Movements Rhythmical Stepping Movements of a Single Limb. Rhythmical stepping movements are frequently observed in the limbs of spinal ani... Reciprocal Stepping of Opposite Limbs. If the lumbar spinal cord is not split down its center, every time stepping occurs in the... Diagonal Stepping of All Four Limbs—“Mark Time” Reflex. If a well-healed spinal animal (with spinal transection in the neck abo... 56 - Cortical and Brain Stem Control of Motor Function Motor Cortex and Corticospinal Tract Primary Motor Cortex Premotor Area Supplementary Motor Area Broca’s Area (Motor Speech Area). Figure 56-3 shows a premotor area labeled “word formation” lying immediately anterior to the ... “Voluntary” Eye Movement Field. In the premotor area immediately above Broca’s area is a locus for controlling voluntary eye mov... Head Rotation Area. Slightly higher in the motor association area, electrical stimulation elicits head rotation. This area is cl... Area for Hand Skills. In the premotor area immediately anterior to the primary motor cortex for the hands and fingers is a regio... Corticospinal (Pyramidal) Tract The Corticorubrospinal System Is an Accessory Pathway for Transmitting Relatively Discrete Signals From the Motor Cortex to the ... Each Column of Neurons Functions as an Integrative Processing System. The neurons of each column operate as an integrative proce... Dynamic and Static Signals Are Transmitted by the Pyramidal Neurons. If a strong signal is sent to a muscle to cause initial rap... Somatosensory Feedback to the Motor Cortex Helps Control Precision of Muscle Contraction Stimulation of the Spinal Motor Neurons Patterns of Movement Elicited by Spinal Cord Centers. From Chapter 55, recall that the spinal cord can provide certain specific ... Control of Motor Functions by the Brain Stem Excitatory-Inhibitory Antagonism Between Pontine and Medullary Reticular Nuclei Pontine Reticular System Transmits Excitatory Signals. The pontine reticular nuclei transmit excitatory signals downward into th... Medullary Reticular System Transmit Inhibitory Signals. The medullary reticular nuclei transmit inhibitory signals to the same a... Role of the Vestibular Nuclei to Excite the Antigravity Muscles The Decerebrate Animal Develops Spastic Rigidity. When the brain stem of an animal is sectioned below the midlevel of the mesenc... Vestibular Apparatus “Maculae”—Sensory Organs of the Utricle and Saccule for Detecting Orientation of the Head With Respect to Gravity. Located on th... Directional Sensitivity of the Hair Cells—Kinocilium. Each hair cell has about 100 small cilia called stereocilia, plus one larg... Semicircular Ducts. The three semicircular ducts in each vestibular apparatus, known as the anterior, posterior, and lateral (ho... Function of the Utricle and Saccule in the Maintenance of Static Equilibrium Detection of Head Rotation by the Semicircular Ducts 57 - Cerebellum and Basal Ganglia Contributions to Overall Motor Control The Cerebellum and its Motor Functions Neuronal Circuit of the Functional Unit. Also shown in the left half of Figure 57-7 is the neuronal circuit of the functional u... Purkinje Cells and Deep Nuclear Cells Fire Continuously Under Normal Resting Conditions. One characteristic of both Purkinje cel... Balance Between Excitation and Inhibition at the Deep Cerebellar Nuclei. Referring again to the circuit of Figure 57-7, note th... Basket Cells and Stellate Cells Cause Lateral Inhibition of Purkinje Cells in the Cerebellum. In addition to the deep nuclear ce... Turn-On/Turn-Off and Turn-Off/Turn-On Output Signals From the Cerebellum The Purkinje Cells “Learn” to Correct Motor Errors—Role of the Climbing Fibers The Vestibulocerebellum Functions in Association With the Brain Stem and Spinal Cord to Control Equilibrium and Postural Movemen... Spinocerebellum—Feedback Control of Distal Limb Movements via the Intermediate Cerebellar Cortex and the Interposed Nucleus Function of the Cerebellum to Prevent Overshoot and to “Damp” Movements. Almost all movements of the body are “pendular.” For ex... Cerebellar Control of Ballistic Movements. Most rapid movements of the body, such as the movements of the fingers in typing, occ... Cerebrocerebellum—Function of the Large Lateral Zone of the Cerebellar Hemisphere to Plan, Sequence, and Time Complex Movements Planning of Sequential Movements. The planning of sequential movements requires that the lateral zones of the hemispheres commun... Timing Function for Sequential Movements. Another important function of the lateral zones of the cerebellar hemispheres is to pr... Extramotor Predictive Functions of the Cerebrocerebellum. The cerebrocerebellum (the large lateral lobes) also helps to “time” e... The Basal Ganglia and Their Motor Functions Neural Pathways of the Putamen Circuit. Figure 57-11 shows the principal pathways through the basal ganglia for executing learn... Integration of the Many Parts of the Total Motor Control System Spinal Level Hindbrain Level Motor Cortex Level Associated Functions of the Cerebellum. The cerebellum functions with all levels of muscle control. It functions with the spinal... Associated Functions of the Basal Ganglia. The basal ganglia are essential to motor control in ways entirely different from thos... What drives us to action 58 - Cerebral Cortex, Intellectual Functions of the Brain, Learning, and Memory Physiologic Anatomy of the Cerebral Cortex Functions of Specific Cortical Areas Association Areas Parieto-Occipitotemporal Association Area Analysis of the Spatial Coordinates of the Body. An area beginning in the posterior parietal cortex and extending into the super... Wernicke’s Area Is Important for Language Comprehension. The major area for language comprehension, called Wernicke’s area, lies... The Angular Gyrus Area Is Needed for Initial Processing of Visual Language (Reading). Posterior to the language comprehension ar... Area for Naming Objects. In the most lateral portions of the anterior occipital lobe and posterior temporal lobe is an area for ... Prefrontal Association Area Broca’s Area Provides the Neural Circuitry for Word Formation. Broca’s area, shown in Figure 58-5, is located partly in the pos... Limbic Association Area Area for Recognition of Faces Angular Gyrus—Interpretation of Visual Information. The angular gyrus is the most inferior portion of the posterior parietal lob... Concept of the Dominant Hemisphere Role of Language in the Function of Wernicke’s Area and in Intellectual Functions Decreased Aggressiveness and Inappropriate Social Responses. Decreased aggressiveness and inappropriate social responses probabl... Inability to Progress Toward Goals or to Carry Through Sequential Thoughts. We learned earlier in this chapter that the prefront... Elaboration of Thought, Prognostication, and Performance of Higher Intellectual Functions by the Prefrontal Areas—Concept of a “... Thoughts, Consciousness, and Memory Positive and Negative Memory—“Sensitization” or “Habituation” of Synaptic Transmission. Although we often think of memories as b... Short-Term Memory Intermediate Long-Term Memory Memory Based on Chemical Changes in Presynaptic Terminals or Postsynaptic Neuronal Membranes Mechanism for Facilitation. In the case of facilitation, at least part of the molecular mechanism is believed to be the followin... Long-Term Memory Structural Changes Occur in Synapses During Development of Long-Term Memory Number of Neurons and Their Connectivities Often Change Significantly During Learning Consolidation of Memory Rehearsal Enhances the Transference of Short-Term Memory Into Long-Term Memory. Studies have shown that rehearsal of the same ... New Memories Are Codified During Consolidation. One of the most important features of consolidation is that new memories are cod... Retrograde Amnesia—Inability to Recall Memories From the Past After Hippocampal or Thalmic Lesions. When retrograde amnesia occu... Hippocampi Are Not Important in Reflexive Learning. People with hippocampal lesions usually do not have difficulty in learning p... 59 - The Limbic System and the Hypothalamus—Behavioral and Motivational Mechanisms of the Brain Activating—Driving Systems Of The Brain Control Of Cerebral Activity By Continuous Excitatory Signals From The Brain Stem Reticular Excitatory Area of the Brain Stem—a Driver of Brain Activity Excitation of the Reticular Excitatory Area by Peripheral Sensory Signals. The level of activity of the reticular excitatory are... Increased Activity of the Excitatory Area Causedby Feedback Signals Returning From the Cerebral Cortex. Not only do excitatory s... The Thalamus Is a Distribution Center That Controls Activity in Specific Regions of the Cortex. As pointed out in Chapter 58, al... A Reticular Inhibitory Area Is Located in the Lower Brain Stem Neurohormonal Systems in the Human Brain. Figure 59-3 shows the brain stem areas in the human brain for activating four neuroho... Other Neurotransmitters and Neurohormonal Substances Secreted in the Brain. Without describing their function, the following is ... Limbic System The Hypothalamus, a Major Control Headquarters for the Limbic System Cardiovascular Regulation. Stimulation of different areas throughout the hypothalamus can cause many neurogenic effects on the c... Body Temperature Regulation. The anterior portion of the hypothalamus, especially the preoptic area, is concerned with regulatio... Body Water Regulation. The hypothalamus regulates body water in two ways: (1) by creating the sensation of thirst, which drives ... Regulation of Uterine Contractility and Milk Ejection from the Breasts. Stimulation of the paraventricular nuclei causes their n... Gastrointestinal and Feeding Regulation. Stimulation of several areas of the hypothalamus causes an animal to experience extreme... Hypothalamic Control of Endocrine Hormone Secretion by the Anterior Pituitary Gland. Stimulation of certain areas of the hypotha... Hypothalamic Control of Circadian Rhythms—The Suprachiasmatic Nucleus. The suprachiasmatic nucleus (SCN) of the hypothalamus con... Summary. Several areas of the hypothalamus control specific vegetative and endocrine functions. The functions of these areas are... Behavioral Functions of the Hypothalamus and Associated Limbic Structures Effects Caused by Stimulation of the Hypothalamus. In addition to the vegetative and endocrine functions of the hypothalamus, st... Reward Centers Punishment Centers Association of Rage With Punishment Centers Placidity and Tameness. Exactly the opposite emotional behavior patterns occur when the reward centers are stimulated—placidity ... Effect of Tranquilizers on the Reward or Punishment Centers. Administration of a tranquilizer, such as chlorpromazine, usually i... Importance of Reward or Punishment in Learning and Memory—Habituation Versus Reinforcement Functions Of The Hippocampus 60 - States of Brain Activity—Sleep, Brain Waves, Epilepsy, Psychoses, and Dementia Sleep REM (Paradoxical, Desynchronized) Sleep Slow-Wave Sleep Basic Theories of Sleep Sleep Is Caused by an Active Inhibitory Process. An earlier theory of sleep was that the excitatory areas of the upper brain ste... Neuronal Centers, Neurohumoral Substances, and Mechanisms That Can Cause Sleep—Possible Role for Serotonin Lesions in Sleep-Promoting Centers Can Cause Intense Wakefulness. Discrete lesions in the raphe nuclei lead to a high state of ... Other Possible Transmitter Substances Related to Sleep. Experiments have shown that the cerebrospinal fluid and the blood or uri... Possible Cause of REM Sleep. It is not understood why slow-wave sleep is broken periodically by REM sleep. However, drugs that ... Cycle Between Sleep and Wakefulness 61 - The Autonomic Nervous System and the Adrenal Medulla General Organization of the Autonomic Nervous System Cholinergic and Adrenergic Fibers—Secretion of Acetylcholine or Norepinephrine Mechanisms of Transmitter Secretion and Removal at Postganglionic Endings Secretion of Acetylcholine and Norepinephrine by Postganglionic Nerve Endings. A few of the postganglionic autonomic nerve endin... Synthesis of Acetylcholine, Its Destruction After Secretion, and Its Duration of Action. Acetylcholine is synthesized in the ter... Synthesis of Norepinephrine, Its Removal, and Its Duration of Action. Synthesis of norepinephrine begins in the axoplasm of the ... Receptors on the Effector Organs Excitation or Inhibition of the Effector Cell by Changing Its Membrane Permeability. Because the receptor protein is an integral... Receptor Action by Altering Intracellular “Second Messenger” Enzymes. Another way a receptor often functions is to activate or i... Two Principal Types of Acetylcholine Receptors—Muscarinic and Nicotinic Receptors Alpha and Beta Adrenergic Receptors Function of the Adrenal Medullae The Adrenal Medullae Support Sympathetic Nervous System Functions. Epinephrine and norepinephrine are almost always released by ... Tone Caused by Basal Secretion of Epinephrine and Norepinephrine by the Adrenal Medullae. The normal resting rate of secretion b... Effect of Loss of Sympathetic or Parasympathetic Tone After Denervation. Immediately after a sympathetic or parasympathetic nerv... Selective Stimulation of Target Organs by Sympathetic and Parasympathetic Systems or “Mass Discharge” The Sympathetic System Sometimes Responds by Mass Discharge. In some cases, almost all portions of the sympathetic nervous syste... The Parasympathetic System Usually Causes Specific Localized Responses. Control functions by the parasympathetic system are ofte... Control of Brain Stem Autonomic Centers by Higher Areas. Signals from the hypothalamus and even from the cerebrum can affect act... 62 - Cerebral Blood Flow, Cerebrospinal Fluid, and Brain Metabolism Cerebral Blood Flow Regulation of Cerebral Blood Flow Excesses of CO2 or H+ Concentration Increase Cerebral Blood Flow. An increase in CO2 concentration in the arterial blood perfusi... Importance of Cerebral Blood Flow Control by CO2 and H+. Increased H+ concentration greatly depresses neuronal activity. Therefo... Oxygen Deficiency as a Regulator of Cerebral Blood Flow. Except during periods of intense brain activity, the rate of O2 utiliza... Cerebral Microcirculation Cerebrospinal Fluid System Secretion by the Choroid Plexus. The choroid plexus, a section of which is shown in Figure 62-6, is a cauliflower-like growth ... Absorption of Cerebrospinal Fluid Through the Arachnoidal Villi. The arachnoidal villi are microscopic fingerlike inward project... Perivascular Spaces and Cerebrospinal Fluid. The large arteries and veins of the brain lie on the surface of the brain but their... Lymphatic Function of the Perivascular Spaces. As is true elsewhere in the body, a small amount of protein leaks out of the brai... Brain Metabolism Total Brain Metabolic Rate and Metabolic Rate of Neurons. Under resting but awake conditions, brain metabolism accounts for abou... Special Requirement of the Brain for Oxygen—Lack of Significant Anaerobic Metabolism. Most tissues of the body can live without ... Under Normal Conditions, Most Brain Energy Is Supplied by Glucose. Under normal conditions, almost all the energy used by the br... 63 - General Principles of Gastrointestinal Function—Motility, Nervous Control, and Blood Circulation Physiologic Anatomy of the Gastrointestinal Wall Gastrointestinal Smooth Muscle Functions as a Syncytium. The individual smooth muscle fibers in the gastrointestinal tract are 2... Electrical Activity of Gastrointestinal Smooth Muscle “Slow Waves” Caused by Undulating Changes in Resting Membrane Potential. Most gastrointestinal contractions occur rhythmically, ... Spike Potentials. The spike potentials are true action potentials. They occur automatically when the resting membrane potential ... Changes in Voltage of the Resting Membrane Potential. In addition to the slow waves and spike potentials, the baseline voltage l... Entry of Calcium Ions Causes Smooth Muscle Contraction. Smooth muscle contraction occurs in response to entry of calcium ions in... Tonic Contraction of Some Gastrointestinal Smooth Muscle. Some smooth muscle of the gastrointestinal tract exhibits tonic contra... Neural Control of Gastrointestinal Function—Enteric Nervous System Autonomic Control of the Gastrointestinal Tract Parasympathetic Stimulation Increases Activity of the Enteric Nervous System. The parasympathetic supply to the gut is divided i... Afferent Sensory Nerve Fibers From the Gut Gastrointestinal Reflexes Hormonal Control of Gastrointestinal Motility Functional Movements in the Gastrointestinal Tract PROPULSIVE MOVEMENTS—PERISTALSIS Function of the Myenteric Plexus in Peristalsis. Peristalsis occurs only weakly or not at all in any portion of the gastrointest... Peristaltic Waves Move Toward the Anus With Downstream Receptive Relaxation—“Law of the Gut.” Peristalsis, theoretically, can oc... Gastrointestinal Blood Flow—Splanchnic Circulation Mechanisms of Increased Blood Flow During Gastrointestinal Activity. Although the precise causes of the increased blood flow dur... “Countercurrent” Blood Flow in the Villi. Note in Figure 63-8 that the arterial flow into the villus and the venous flow out of... Importance of Nervous Depression of Gastrointestinal Blood Flow When Other Parts of the Body Need Extra Blood Flow. A major valu... 64 - Propulsion and Mixing of Food in the Alimentary Tract Ingestion of Food Mastication (Chewing) Swallowing (Deglutition) Voluntary Stage of Swallowing. When the food is ready for swallowing, it is “voluntarily” squeezed or rolled posteriorly into th... Involuntary Pharyngeal Stage of Swallowing. As the bolus of food enters the posterior mouth and pharynx, it stimulates epithelia... Nervous Initiation of the Pharyngeal Stage of Swallowing. The most sensitive tactile areas of the posterior mouth and pharynx fo... The Pharyngeal Stage of Swallowing Momentarily Interrupts Respiration. The entire pharyngeal stage of swallowing usually occurs ... The Esophageal Stage of Swallowing Involves Two Types of Peristalsis. The esophagus functions primarily to conduct food rapidly ... Receptive Relaxation of the Stomach. When the esophageal peristaltic wave approaches the stomach, a wave of relaxation, transmit... Function of the Lower Esophageal Sphincter (Gastroesophageal Sphincter). At the lower end of the esophagus, extending upward abo... Prevention of Esophageal Reflux by Valvelike Closure of the Distal End of the Esophagus. Another factor that helps prevent reflu... Motor Functions of the Stomach Storage Function of the Stomach Chyme. After food in the stomach has become thoroughly mixed with the stomach secretions, the resulting mixture that passes down... Hunger Contractions. Besides the peristaltic contractions that occur when food is present in the stomach, another type of intens... Stomach Emptying Intense Antral Peristaltic Contractions During Stomach Emptying—“Pyloric Pump.” Most of the time, the rhythmic stomach contracti... Role of the Pylorus in Controlling Stomach Emptying. The distal opening of the stomach is the pylorus. Here the thickness of the... Regulation of Stomach Emptying The Hormone Gastrin Promotes Stomach Emptying. In Chapter 65, we discuss how stretching of the stomach wall and the presence of ... Hormonal Feedback From the Duodenum Inhibits Gastric Emptying—Role of Fats and the Hormone Cholecystokinin. Hormones released fr... Summary of the Control of Stomach Emptying Movements of the Small Intestine Propulsive Movements Peristalsis in the Small Intestine. Chyme is propelled through the small intestine by peristaltic waves, as discussed in Chapter... Control of Peristalsis by Nervous and Hormonal Signals. Peristaltic activity of the small intestine increases markedly after a m... Propulsive Effect of the Segmentation Movements. The segmentation movements, although lasting for only a few seconds at a time, ... Powerful, Rapid Peristalsis—“Peristaltic Rush.” Although peristalsis in the small intestine is normally weak, intense irritation... Feedback Control of the Ileocecal Sphincter by Reflexes From the Cecum. The degree of contraction of the ileocecal sphincter and... Movements of the Colon Mixing Movements—“Haustrations.” In the same manner that segmentation movements occur in the small intestine, large circular con... Propulsive Movements—“Mass Movements.” Much of the propulsion in the cecum and ascending colon results from the slow but persist... Initiation of Mass Movements by Gastrocolic and Duodenocolic Reflexes. The appearance of mass movements after meals is facilitat... Defecation Other Autonomic Reflexes That Affect Bowel Activity 65 - Secretory Functions of the Alimentary Tract Basic Mechanisms of Stimulation of the Alimentary Tract Glands Contact of Food With Gut Epithelium Activates the Enteric Nervous System and Stimulates Secretion Sympathetic Stimulation Has a Dual Effect on Alimentary Tract Glandular Secretion Rate. Stimulation of the sympathetic nerves go... Regulation of Glandular Secretion by Hormones. In the stomach and intestine, several different gastrointestinal hormones help re... Basic Mechanism of Secretion by Glandular Cells Secretion of Organic Substances. Although all the basic mechanisms by which glandular cells function are not known, experimental... Secretion of Saliva Saliva Contains a Serous Secretion and a Mucus Secretion. The principal glands of salivation are the parotid, submandibular, and... Gastric Secretion Secretions From the Gastric (Oxyntic) Glands Basic Mechanism of Hydrochloric Acid Secretion. When stimulated, the parietal cells secrete an acid solution that contains about... The Basic Factors That Stimulate Gastric Secretion Are Acetylcholine, Gastrin, and Histamine. Acetylcholine released by parasymp... Secretion and Activation of Pepsinogen. Several slightly different types of pepsinogen are secreted by the peptic and mucous cel... Secretion of Intrinsic Factor by Parietal Cells. The substance intrinsic factor, which is essential for vitamin B12 absorption i... Surface Mucous Cells Stimulation of Gastric Acid Secretion Parietal Cells of the Oxyntic Glands Are the Only Cells That Secrete Hydrochloric Acid. As noted earlier in the chapter, the aci... Regulation of Pepsinogen Secretion Pancreatic Secretion Pancreatic Digestive Enzymes Secretion of Bicarbonate Ions Regulation of Pancreatic Secretion Basic Stimuli That Cause Pancreatic Secretion Phases of Pancreatic Secretion Cephalic and Gastric Phases. During the cephalic phase of pancreatic secretion, the same nervous signals from the brain that cau... Intestinal Phase. After chyme leaves the stomach and enters the small intestine, pancreatic secretion becomes copious, mainly in... Secretin Stimulates Copious Secretion of Bicarbonate Ions, Which Neutralizes Acidic Stomach Chyme. Secretin is a polypeptide con... Cholecystokinin Contributes to Control of Digestive Enzyme Secretion by the Pancreas. The presence of food in the upper small in... Bile Secretion by the Liver The Gallbladder Stores and Concentrates Bile. Bile is secreted continually by the liver cells, but most of it is normally stored... Composition of Bile. Table 65-2 lists the composition of bile when it is first secreted by the liver and then after it has been... Cholecystokinin Stimulates Gallbladder Emptying. When food begins to be digested in the upper gastrointestinal tract, the gallbl... Secretions of the Small Intestine Secretion of Mucus by Brunner's Glands in the Duodenum Mechanism of Secretion of the Watery Fluid. The exact mechanism that controls the marked secretion of watery fluid by the crypts... Digestive Enzymes in the Small Intestinal Secretion. When secretions of the small intestine are collected without cellular debri... Secretion of Mucus by The Large Intestine 66 - Digestion and Absorption in the Gastrointestinal Tract Hydrolysis of Carbohydrates. Almost all the carbohydrates of the diet are either large polysaccharides or disaccharides, which a... Hydrolysis of Fats. Almost the entire fat portion of the diet consists of triglycerides (neutral fats), which are combinations o... Digestion of Carbohydrates Carbohydrate Foods of the Diet. Only three major sources of carbohydrates exist in the normal human diet. They are sucrose, whic... Digestion of Carbohydrates in the Small Intestine Digestion by Pancreatic Amylase. Pancreatic secretion, like saliva, contains a large quantity of α-amylase that is almost ident... Digestion of Proteins Proteins of the Diet. Dietary proteins are chemically long chains of amino acids bound together by peptide linkages. A typical l... Digestion of Proteins in the Stomach. Pepsin, an important peptic enzyme of the stomach, is most active at a pH of 2.0 to 3.0 an... Most Protein Digestion Results From Actions of Pancreatic Proteolytic Enzymes. Most protein digestion occurs in the upper small ... Digestion of Peptides by Peptidases in the Enterocytes That Line the Small Intestinal Villi. The last digestive stage of protein... Digestion of Fats Fats of the Diet. By far the most abundant fats of the diet are the neutral fats, also known as triglycerides, each molecule of ... Digestion of Fats Occurs Mainly in the Small Intestine. A small amount of triglycerides is digested in the stomach by lingual li... The First Step in Fat Digestion Is Emulsification by Bile Acids and Lecithin. The first step in fat digestion is to physically b... Triglycerides Are Digested by Pancreatic Lipase. By far the most important enzyme for digestion of the triglycerides is pancreat... End Products of Fat Digestion Are Free Fatty Acids. Most of the triglycerides of the diet are split by pancreatic lipase into fr... Bile Salts Form Micelles That Accelerate Fat Digestion. The hydrolysis of triglycerides is a highly reversible process; therefor... Digestion of Cholesterol Esters and Phospholipids. Most cholesterol in the diet is in the form of cholesterol esters, which are ... Basic Principles of Gastrointestinal Absorption Anatomical Basis of Absorption Absorption in the Small Intestine Isosmotic Absorption of Water Absorption of Ions Sodium Is Actively Transported Through the Intestinal Membrane. Twenty to 30 grams of sodium are secreted in the intestinal secr... Osmosis of the Water. The next step in the transport process is osmosis of water by transcellular and paracellular pathways. Thi... Aldosterone Greatly Enhances Sodium Absorption. When a person becomes dehydrated, large amounts of aldosterone are secreted by t... Absorption of Chloride Ions in the Small Intestine. In the upper part of the small intestine, chloride ion absorption is rapid a... Absorption of Bicarbonate Ions in the Duodenum and Jejunum. Often large quantities of bicarbonate ions (HCO3−) must be reabsorbe... Secretion of Bicarbonate and Absorption of Chloride Ions in the Ileum and Large Intestine. The epithelial cells on the surfaces ... Active Absorption of Calcium, Iron, Potassium, Magnesium, and Phosphate. Calcium ions are actively absorbed into the blood, espe... Absorption of Nutrients Carbohydrates Are Mainly Absorbed as Monosaccharides Glucose Is Transported by a Sodium Co-Transport Mechanism. In the absence of sodium transport through the intestinal membrane, ... Absorption of Other Monosaccharides. Galactose is transported by almost exactly the same mechanism as glucose, using the SGLT1 a... Absorption of Proteins as Dipeptides, Tripeptides, or Amino Acids Absorption of Fats Direct Absorption of Fatty Acids Into the Portal Blood. Small quantities of short- and medium-chain fatty acids, such as those... Absorption in the Large Intestine: Formation of Feces Absorption and Secretion of Electrolytes and Water. The mucosa of the large intestine, like that of the small intestine, has a h... Maximum Absorption Capacity of the Large Intestine. The large intestine can absorb a maximum of 5 to 8 liters of fluid and elect... Composition of the Feces. The feces normally are about three-fourths water and one-fourth solid matter that is composed of abo... 67 - Physiology of Gastrointestinal Disorders 68 - Metabolism of Carbohydrates and Formation of Adenosine Triphosphate 69 - Lipid Metabolism Basic Chemical Structure of Triglycerides (Neutral Fat) Transport of Triglycerides and Other Lipids From the Gastrointestinal Tract by Lymph—the Chylomicrons 70 - Protein Metabolism 71 - The Liver 72 - Dietary Balances; Regulation of Feeding; Obesity and Starvation; Vitamins and Minerals ENERGY INTAKE AND OUTPUT BALANCED UNDER STEADY-STATE CONDITIONS REGULATION OF FOOD INTAKE AND ENERGY STORAGE The Hypothalamus Contains Hunger and Satiety Centers. Several neuronal centers of the hypothalamus participate in the control of... Neurons and Neurotransmitters in the Hypothalamus That Stimulate or Inhibit Feeding. Two distinct types of neurons in the arcua... Neural Centers That Influence the Mechanical Process of Feeding. Another aspect of feeding is the mechanical act of the feeding ... Short-Term Regulation of Food Intake Gastrointestinal Filling Inhibits Feeding. When the gastrointestinal tract becomes distended, especially the stomach and the duo... Gastrointestinal Hormonal Factors Suppress Feeding. CCK, which is released mainly in response to fat and proteins entering the d... Ghrelin, a Gastrointestinal Hormone, Increases Feeding. Ghrelin is a hormone released mainly by the oxyntic cells of the stomac... Oral Receptors Meter Food Intake. When an animal with an esophageal fistula is fed large quantities of food, even though this fo... Intermediate- and Long-Term Regulation of Food Intake Effect of Blood Concentrations of Glucose, Amino Acids, and Lipids on Hunger and Feeding. Temperature Regulation and Food Intake Feedback Signals From Adipose Tissue Regulate Food Intake. Importance of Having Both Long- and Short-Term Regulatory Systems for Feeding 73 - Energetics and Metabolic Rate 74 - Body Temperature Regulation and Fever Normal Body Temperatures Body Core Temperature and Skin Temperature. The temperature of the deep tissues of the body—the “core” of the body—usually remai... Body Temperature is Controlled by Balancing Heat Production and Heat Loss Heat Production Heat Loss Insulator System of the Body Blood Flow to the Skin From the Body Core Provides Heat Transfer Control of Heat Conduction to the Skin by the Sympathetic Nervous System. Heat conduction to the skin by the blood is controlled... Basic Physics of Heat Loss From the Skin Surface Radiation Causes Heat Loss in the Form of Infrared Rays. As shown in Figure 74-4, in a nude person sitting inside at normal roo... Conductive Heat Loss Occurs by Direct Contact With an Object. As shown in Figure 74-4, only minute quantities of heat, about 3%... Convective Heat Loss Results From Air Movement. Heat from the skin is first conducted to the air and then carried away by the co... Cooling Effect of Wind. When the body is exposed to wind, the layer of air immediately adjacent to the skin is replaced by new a... Conduction and Convection of Heat From a Person Suspended in Water. Water has a specific heat several thousand times as great as... Evaporation Evaporation is a Necessary Cooling Mechanism at Very High Air Temperatures. As long as skin temperature is greater than the temp... Clothing Reduces Conductive and Convective Heat Loss. Clothing entraps air next to the skin in the weave of the cloth, thereby i... Sweating and Its Regulation by the Autonomic Nervous System Mechanism of Sweat Secretion. In Figure 74-5, the sweat gland is shown to be a tubular structure consisting of two parts: (1) a... Acclimatization of the Sweating Mechanism to Heat—The Role of Aldosterone. Although a normal, unacclimatized person seldom produ... Regulation of Body Temperature—Role of the Hypothalamus Temperature-Decreasing Mechanisms When the Body Is Too Hot Temperature-Increasing Mechanisms When the Body Is Too Cold Hypothalamic Stimulation of Shivering. Located in the dorsomedial portion of the posterior hypothalamus near the wall of the thi... Sympathetic “Chemical” Excitation of Heat Production. As noted in Chapter 73, an increase in either sympathetic stimulation or c... Increased Thyroxine Output as a Long-Term Cause of Increased Heat Production. Cooling the anterior hypothalamic-preoptic area ... Feedback Gain for Body Temperature Control. As discussed in Chapter 1, feedback gain is a measure of the effectiveness of a cont... Skin Temperature Can Slightly Alter the Set Point for Core Temperature Control Fever Resetting the Hypothalamic Temperature-Regulating Center in Febrile Diseases—Effect of Pyrogens Mechanism of Action of Pyrogens in Causing Fever—Role of Cytokines. Experiments in animals have shown that some pyrogens, when i... Fever Caused by Brain Lesions. When a brain surgeon operates in the region of the hypothalamus, severe fever almost always occur... 75 - Introduction to Endocrinology Coordination of Body Functions by Chemical Messengers Chemical Structure and Synthesis of Hormones Polypeptide and Protein Hormones Are Stored in Secretory Vesicles Until Needed. Most of the hormones in the body are polypeptide... Steroid Hormones Are Usually Synthesized From Cholesterol and Are Not Stored. Steroid hormones have a chemical structure that is... Amine Hormones Are Derived From Tyrosine. The two groups of hormones derived from tyrosine, the thyroid and the adrenal medullar... Hormone Secretion After a Stimulus and Duration of Action of Different Hormones. Some hormones, such as norepinephrine and epine... Concentrations of Hormones in the Circulating Blood and Hormonal Secretion Rates. The concentrations of hormones required to con... Feedback Control of Hormone Secretion Negative Feedback Prevents Overactivity of Hormone Systems. Although the plasma concentrations of many hormones fluctuate in re... Surges of Hormones Can Occur With Positive Feedback. In a few cases, positive feedback occurs when the biological action of the ... Cyclical Variations Occur in Hormone Release. Superimposed on the negative and positive feedback control of hormone secretion ar... “Clearance” of Hormones From the Blood. Two factors can increase or decrease the concentration of a hormone in the blood: (1) th... Hormone Receptors and their Activation The Number and Sensitivity of Hormone Receptors Are Regulated. The number of receptors in a target cell usually does not remain ... Ion Channel–Linked Receptors. Virtually all the neurotransmitter substances, such as acetylcholine and norepinephrine, combine w... G Protein–Linked Hormone Receptors. Many hormones activate receptors that indirectly regulate the activity of target proteins (e... Enzyme-Linked Hormone Receptors. Some receptors, when activated, function directly as enzymes or are closely associated with en... Intracellular Hormone Receptors and Activation of Genes. Several hormones, including adrenal and gonadal steroid hormones, thyro... Adenylyl Cyclase–cAMP Second Messenger System Cell Membrane Phospholipid Second Messenger System Calcium-Calmodulin Second Messenger System Hormones that Act Mainly on the Genetic Machinery of the Cell Steroid Hormones Increase Protein Synthesis Thyroid Hormones Increase Gene Transcription in the Cell Nucleus 76 - Pituitary Hormones and Their Control by the Hypothalamus Hypothalamus Controls Pituitary Secretion Physiological Functions of Growth Hormone Growth Hormone Promotes Protein Deposition in Tissues Growth Hormone Enhances Fat Utilization for Energy Growth Hormone Decreases Carbohydrate Utilization Necessity of Insulin and Carbohydrate for the Growth-Promoting Action of Growth Hormone Hypothalamic Growth Hormone–Releasing Hormone Stimulates, and Somatostatin Inhibits Growth Hormone Secretion Posterior Pituitary Gland and its Relation to the Hypothalamus Regulation of Antidiuretic Hormone Production Physiological Functions of Oxytocin 77 - Thyroid Metabolic Hormones Synthesis and Secretion of the Thyroid Metabolic Hormones Thyroglobulin and Formation of Thyroxine and Triiodothyronine Formation and Secretion of Thyroglobulin by the Thyroid Cells. The thyroid cells are typical protein-secreting glandular cells,... Oxidation of the Iodide Ion.The first essential step in thyroid hormone formation is conversion of iodide ions to an oxidized fo... Iodination of Tyrosine and Thyroid Hormone Formation—“Organification” of Thyroglobulin. The binding of iodine with the thyroglob... Storage of Thyroglobulin.The thyroid gland is unusual among the endocrine glands in its ability to store large amounts of hormon... Daily Rate of Secretion of Thyroxine and Triiodothyronine.About 93% of the thyroid hormone released from the thyroid gland is no... Transport of Thyroxine and Triiodothyronine to Tissues Thyroxine and Triiodothyronine Are Bound to Plasma Proteins.Upon entering the blood, more than 99% of the thyroxine and triiodot... Thyroxine and Triiodothyronine Are Released Slowly to Tissue Cells. Because of high affinity of the plasma-binding proteins for... Thyroid Hormones Have Slow Onset and Long Duration of Action.After injection of a large quantity of thyroxine into a human being... Thyroid Hormones Increase Transcription of Many Genes Most of the Thyroxine Secreted by the Thyroid Is Converted to Triiodothyronine. Before acting on the genes to increase genetic t... Thyroid Hormones Activate Nuclear Receptors. Thyroid hormone receptors are either attached to the DNA genetic strands or located... Thyroid Hormones Increase the Number and Activity of Mitochondria. When thyroxine or triiodothyronine is given to an animal, the... Thyroid Hormones Increase Active Transport of Ions Through Cell Membranes. One of the enzymes that increases its activity in res... Effects of Thyroid Hormone on Specific Body Functions Stimulation of Carbohydrate Metabolism.Thyroid hormone stimulates almost all aspects of carbohydrate metabolism, including rapid... Stimulation of Fat Metabolism. Essentially all aspects of fat metabolism are also enhanced by thyroid hormone. In particular, li... Effect on Plasma and Liver Fats. Increased thyroid hormone decreases the concentrations of cholesterol, phospholipids, and trigl... Increased Requirement for Vitamins. Because thyroid hormone increases the quantities of many bodily enzymes and because vitamins... Increased Basal Metabolic Rate. Because thyroid hormone increases metabolism in almost all cells of the body, excessive quantiti... Decreased Body Weight.A greatly increased amount of thyroid hormone almost always decreases body weight, and a greatly decreased... Increased Blood Flow and Cardiac Output. Increased metabolism in the tissues causes more rapid utilization of oxygen than normal... Increased Heart Rate.The heart rate increases considerably more under the influence of thyroid hormone than would be expected fr... Increased Heart Strength.A slight excess of thyroid hormone can increase the strength of the heart. This effect is analogous to ... Normal Arterial Pressure. The mean arterial pressure usually remains about normal after administration of thyroid hormone. Becau... Increased Respiration. The increased rate of metabolism increases oxygen utilization and carbon dioxide formation; these effects... Increased Gastrointestinal Motility. In addition to increased appetite and food intake, which has been discussed, thyroid hormon... Excitatory Effects on the Central Nervous System.In general, thyroid hormone increases the rapidity of cerebration, although tho... Effect on the Function of the Muscles.A slight increase in thyroid hormone usually makes the muscles react with vigor but, with ... Muscle Tremor.One of the most characteristic signs of hyperthyroidism is a fine muscle tremor. This symptom is not the coarse tr... Effect on Sleep. Because of the exhausting effect of thyroid hormone on the musculature and on the central nervous system, perso... Effect on Other Endocrine Glands. Increased thyroid hormone increases the secretion rates of several other endocrine glands, but... Effect of Thyroid Hormone on Sexual Function. For normal sexual function, thyroid secretion needs to be approximately normal. In... Regulation of Thyroid Hormone Secretion Cyclic Adenosine Monophosphate Mediates the Stimulatory Effect of TSH. Most of the varied effects of TSH on the thyroid cell res... 78 - Adrenocortical Hormones Corticosteroids: Mineralocorticoids, Glucocorticoids, and Androgens The Adrenal Cortex has Three Distinct Layers Mineralocorticoid Deficiency Causes Severe Renal Sodium Chloride Wasting and Hyperkalemia. Total loss of adrenocortical secretio... Aldosterone Is the Major Mineralocorticoid Secreted by the Adrenals. In humans, aldosterone exerts nearly 90% of the mineralocor... Renal and Circulatory Effects of Aldosterone Aldosterone Increases Renal Tubular Reabsorption of Sodium and Secretion of Potassium. As discussed in Chapter 28, aldosterone i... Excess Aldosterone Increases Extracellular Fluid Volume and Arterial Pressure But Has Only a Small Effect on Plasma Sodium Conce... Excess Aldosterone Causes Hypokalemia and Muscle Weakness; Aldosterone Deficiency Causes Hyperkalemia and Cardiac Toxicity. Exce... Excess Aldosterone Increases Tubular Hydrogen Ion Secretion and Causes Alkalosis. Aldosterone not only causes potassium to be se... Functions of Glucocorticoids Effects of Cortisol on Carbohydrate Metabolism Stimulation of Gluconeogenesis. The best-known metabolic effect of cortisol and other glucocorticoids on metabolism is the abil... Decreased Glucose Utilization by Cells. Cortisol also causes a moderate decrease in glucose utilization by most cells in the bod... Elevated Blood Glucose Concentration and “Adrenal Diabetes.” Both the increased gluconeogenesis and moderate reduction in glucos... Effects of Cortisol on Protein Metabolism Reduction in Cellular Protein. One of the principal effects of cortisol on the metabolic systems of the body is reduction of pro... Cortisol Increases Liver and Plasma Proteins. Coincidentally with the effect of glucocorticoids to reduce proteins elsewhere in ... Increased Blood Amino Acids, Diminished Transport of Amino Acids Into Extrahepatic Cells, and Enhanced Transport Into Hepatic Ce... Effects of Cortisol on Fat Metabolism Mobilization of Fatty Acids. In much the same manner that cortisol promotes amino acid mobilization from muscle, it also promote... Anti-inflammatory Effects of High Levels of Cortisol Cortisol Prevents the Development of Inflammation by Stabilizing Lysosomes and by Other Effects. Cortisol has the following effe... Cortisol Causes Resolution of Inflammation. Even after inflammation has become well established, administration of cortisol can ... Regulation of Cortisol Secretion by Adrenocorticotropic Hormone from the Pituitary Gland ACTH Stimulates Cortisol Secretion. Unlike aldosterone secretion by the zona glomerulosa, which is controlled mainly by potassiu... Chemistry of ACTH. ACTH has been isolated in pure form from the anterior pituitary. It is a large polypeptide, having a chain le... ACTH Secretion Is Controlled by Corticotropin-Releasing Factor From the Hypothalamus. In the same way that other pituitary horm... ACTH Activates Adrenocortical Cells to Produce Steroids by Increasing cAMP. The principal effect of ACTH on the adrenocortical c... Physiological Stress Increases ACTH and Adrenocortical Secretion. As pointed out earlier in the chapter, almost any type of phys... Inhibitory Effect of Cortisol on the Hypothalamus and Anterior Pituitary to Decrease ACTH Secretion. Cortisol has direct negativ... Summary of the Cortisol Control System Synthesis and Secretion of ACTH in Association With Melanocyte-Stimulating Hormone, Lipotropin, and Endorphin 79 - Insulin, Glucagon, and Diabetes Mellitus Insulin and its Metabolic Effects Insulin Promotes Muscle Glucose Uptake and Metabolism Quantitative Effect of Insulin to Facilitate Glucose Transport Through the Muscle Cell Membrane Insulin Promotes Liver Uptake, Storage, and Use of Glucose Glucose Is Released From the Liver Between Meals. When the blood glucose level begins to fall to a low level between meals, seve... Insulin Promotes Conversion of Excess Glucose Into Fatty Acids and Inhibits Gluconeogenesis in the Liver. When the quantity of g... Lack of Effect of Insulin on Glucose Uptake and Usage by the Brain Effect of Insulin on Carbohydrate Metabolism in Other Cells Effect of Insulin on Fat Metabolism Insulin Promotes Fat Synthesis and Storage Role of Insulin in Storage of Fat in the Adipose Cells. Insulin has two other essential effects that are required for fat storag... Insulin Deficiency Increases Use of Fat for Energy Insulin Deficiency Causes Lipolysis of Storage Fat and Release of Free Fatty Acids. In the absence of insulin, all the effects o... Insulin Deficiency Increases Plasma Cholesterol and Phospholipid Concentrations. The excess of fatty acids in the plasma associa... Excess Usage of Fats During Insulin Deficiency Causes Ketosis and Acidosis. Insulin deficiency also causes excessive amounts of ... Effect of Insulin on Protein Metabolism and Growth Insulin Promotes Protein Synthesis and Storage Insulin Deficiency Causes Protein Depletion and Increased Plasma Amino Acids Insulin and Growth Hormone Interact Synergistically to Promote Growth Mechanisms of Insulin Secretion Control of Insulin Secretion Increased Blood Glucose Stimulates Insulin Secretion. At the normal fasting level of blood glucose of 80 to 90 mg/100 ml, the ra... Feedback Relation Between Blood Glucose Concentration and the Insulin Secretion Rate. As blood glucose concentration rises above... Glucagon and its Functions Effects on Glucose Metabolism Glucagon Causes Glycogenolysis and Increased Blood Glucose Concentration Glucagon Increases Gluconeogenesis Other Effects of Glucagon Regulation of Glucagon Secretion Increased Blood Glucose Inhibits Glucagon Secretion. Blood glucose concentration is by far the most potent factor that controls ... Increased Blood Amino Acids Stimulate Secretion of Glucagon. High concentrations of amino acids, such as those that occur in the... Exercise Stimulates Secretion of Glucagon. During exhaustive exercise, blood glucagon concentration often increases fourfold to ... Summary of Blood Glucose Regulation 80 - Parathyroid Hormone, Calcitonin, Calcium and Phosphate Metabolism, Vitamin D, Bone, and Teeth Overview of Calcium and Phosphate Regulation in Extracellular Fluid and Plasma Hypocalcemia Causes Nervous System Excitement and Tetany. When the extracellular fluid concentration of calcium ions falls below... Absorption and Excretion of Calcium and Phosphate Intestinal Absorption and Fecal Excretion of Calcium and Phosphate. The usual rates of intake are approximately 1000 mg/day each... Bone and its Relationship to Extracellular Calcium and Phosphate Organic Matrix of Bone. The organic matrix of bone is 90% to 95% collagen fibers, and the remainder is a homogeneous gelatinous ... Bone Salts. The crystalline salts deposited in the organic matrix of bone are composed principally of calcium and phosphate. The... Tensile and Compressional Strength of Bone. Each collagen fiber of cortical (compact) bone is composed of repeating periodic seg... Precipitation and Absorption of Calcium and Phosphate in Bone—Equilibrium With the Extracellular Fluids Hydroxyapatite Does Not Precipitate in Extracellular Fluid Despite Supersaturation of Calcium and Phosphate Ions. The concentrat... Mechanism of Bone Calcification. The initial stage in bone production is secretion of collagen molecules (called collagen monome... Precipitation of Calcium in Nonosseous Tissues Under Abnormal Conditions. Although calcium salts usually do not precipitate in n... Deposition and Resorption of Bone—Remodeling of Bone Deposition of Bone by the Osteoblasts. Bone is continually being deposited by osteoblasts, and it is continually being resorbed ... Resorption of Bone—Function of the Osteoclasts. Bone is also being continually resorbed in the presence of osteoclasts, which ar... Bone Deposition and Resorption Are Normally in Equilibrium. Except in growing bones, the rates of bone deposition and resorption... Value of Continual Bone Remodeling. The continual deposition and resorption of bone have several important functions. First, bon... Control of the Rate of Bone Deposition by Bone “Stress” Bone is deposited in proportion to the compressional load that the bone ... Vitamin D Cholecalciferol (Vitamin D3) Is Formed in the Skin. Several compounds derived from sterols belong to the vitamin D family, and t... Cholecalciferol Is Converted to 25-Hydroxycholecalciferol in the Liver. The first step in the activation of cholecalciferol is... Formation of 1,25-Dihydroxycholecalciferol in the Kidneys and Its Control by Parathyroid Hormone. Figure 80-8 also shows the c... Calcium Ion Concentration Controls the Formation of 1,25-Dihydroxycholecalciferol. Figure 80-10 demonstrates that plasma conce... Actions of Vitamin D “Hormonal” Effect of Vitamin D to Promote Intestinal Calcium Absorption. 1,25-Dihydroxycholecal- ciferol functions as a type o... Vitamin D Promotes Phosphate Absorption by the Intestines. Although phosphate is usually absorbed easily, phosphate flux through... Vitamin D Decreases Renal Calcium and Phosphate Excretion. Vitamin D also increases calcium and phosphate reabsorption by the ep... Effect of Vitamin D on Bone and Its Relation to Parathyroid Hormone Activity. Vitamin D plays important roles in bone resorption... Parathyroid Hormone Parathyroid Hormone Mobilizes Calcium and Phosphate From Bone Rapid Phase of Calcium and Phosphate Mobilization From Bone—Osteolysis. When large quantities of PTH are injected, calcium ion c... Slow Phase of Bone Resorption and Calcium Phosphate Release—Activation of the Osteoclasts. A much better known effect of PTH and... Parathyroid Hormone Decreases Calcium Excretion and Increases Phosphate Excretion by the Kidneys Parathyroid Hormone Increases Intestinal Absorption of Calcium and Phosphate Cyclic Adenosine Monophosphate Mediates the Effects of Parathyroid Hormone. A large share of the effect of PTH on its target org... Calcitonin Increased Plasma Calcium Concentration Stimulates Calcitonin Secretion. The primary stimulus for calcitonin secretion is increas... Calcitonin Decreases Plasma Calcium Concentration. In some young animals, calcitonin decreases blood calcium ion concentration r... Calcitonin Has a Weak Effect on Plasma Calcium Concentration in Adult Humans. The reason for the weak effect of calcitonin on pl... Summary of Control of Calcium ion Concentration Buffer Function of the Exchangeable Calcium in Bones—The First Line of Defense. The exchangeable calcium salts in the bones, dis... Physiology of the Teeth Enamel. The outer surface of the tooth is covered by a layer of enamel that is formed before eruption of the tooth by special ep... Dentin. The main body of the tooth is composed of dentin, which has a strong bony structure. Dentin is made up principally of hy... Cementum. Cementum is a bony substance secreted by cells of the periodontal membrane, which lines the tooth socket. Many collage... Pulp. The pulp cavity of each tooth is filled with pulp, which is composed of connective tissue with an abundant supply of nerve... Dentition. Humans and most other mammals develop two sets of teeth during a lifetime. The first teeth are called deciduous teeth... Formation of the Teeth. Figure 80-16 shows the formation and eruption of teeth. Figure 80-16A shows invagination of the oral e... Eruption of Teeth. During early childhood, the teeth begin to protrude outward from the bone through the oral epithelium into th... Development of the Permanent Teeth. During embryonic life, a tooth-forming organ also develops in the deeper dental lamina for ... Metabolic Factors Influence Development of the Teeth. The rate of development and the speed of eruption of teeth can be accelera... Mineral Exchange in Teeth. The salts of teeth, like those of bone, are composed of hydroxyapatite with adsorbed carbonates and v... 81 - Reproductive and Hormonal Functions of the Male (and Function of the Pineal Gland) Spermatogenesis Steps of Spermatogenesis Meiosis. Spermatogonia that cross the barrier into the Sertoli cell layer become progressively modified and enlarged to form lar... Sex Chromosomes. In each spermatogonium, one of the 23 pairs of chromosomes carries the genetic information that determines the ... Formation of Sperm. When the spermatids are first formed, they still have the usual characteristics of epithelioid cells, but so... Hormonal Factors That Stimulate Spermatogenesis Maturation of Sperm in the Epididymis Storage of Sperm in the Testes. The two testes of the human adult form up to 120 million sperm each day. Most of these sperm are... Physiology of the Mature Sperm. The normal motile, fertile sperm are capable of flagellated movement through the fluid medium at... Function of the Seminal Vesicles Function of the Prostate Gland Semen “Capacitation” of Spermatozoa Is Required for Fertilization of the Ovum Acrosome Enzymes, the “Acrosome Reaction,” and Penetration of the Ovum Why Does Only One Sperm Enter the Oocyte With as many sperm as there are, why does only one enter the oocyte The reason is not e... Male Sexual Act Neuronal Stimulus for Performance of the Male Sexual Act Psychic Element of Male Sexual Stimulation. Appropriate psychic stimuli can greatly enhance the ability of a person to perform t... Integration of the Male Sexual Act in the Spinal Cord. Although psychic factors usually play an important part in the male sexua... Stages of the Male Sexual Act Penile Erection—Role of the Parasympathetic Nerves. Penile erection is the first effect of male sexual stimulation, and the degr... Lubrication Is a Parasympathetic Function. During sexual stimulation, the parasympathetic impulses, in addition to promoting ere... Emission and Ejaculation Are Functions of the Sympathetic Nerves. Emission and ejaculation are the culmination of the male sexua... Secretion, Metabolism, and Chemistry of the Male Sex Hormones Functions of Testosterone Functions of Testosterone During Fetal Development Effect of Testosterone to Cause Descent of the Testes. The testes usually descend into the scrotum during the last 2 to 3 months... Effect of Testosterone on Development of Adult Primary and Secondary Sexual Characteristics Effect on the Distribution of Body Hair. Testosterone causes growth of hair (1) over the pubis, (2) upward along the linea alba ... Male Pattern Baldness. Testosterone decreases the growth of hair on the top of the head; a man who does not have functional test... Effect on the Voice. Testosterone secreted by the testes or injected into the body causes hypertrophy of the laryngeal mucosa an... Testosterone Increases Thickness of the Skin and Can Contribute to Development of Acne. Testosterone increases the thickness of ... Testosterone Increases Protein Formation and Muscle Development. One of the most important male characteristics is development o... Testosterone Increases Bone Matrix and Causes Calcium Retention. After the great increase in circulating testosterone that occur... Testosterone Increases the Basal Metabolic Rate. Injection of large quantities of testosterone can increase the basal metabolic ... Testosterone Increases Red Blood Cells. When normal quantities of testosterone are injected into a castrated adult, the number o... Effect on Electrolyte and Water Balance. As pointed out in Chapter 78, many steroid hormones can increase the reabsorption of so... Gonadotropin-Releasing Hormone Increases Secretion of Luteinizing Hormone and Follicle-Stimulating Hormone Gonadotropic Hormones: Luteinizing Hormone and Follicle-Stimulating Hormone Regulation of Testosterone Production by Luteinizing Hormone. Testosterone is secreted by the interstitial cells of Leydig in th... Inhibition of Anterior Pituitary Secretion of Luteinizing and Follicle-Stimulating Hormones by Testosterone—Negative Feedback C... Regulation of Spermatogenesis by Follicle-Stimulating Hormone and Testosterone Role of Inhibin in Negative Feedback Control of Seminiferous Tubule Activity. When the seminiferous tubules fail to produce sper... Human Chorionic Gonadotropin Secreted by the Placenta During Pregnancy Stimulates Testosterone Secretion by the Fetal Testes Puberty and Regulation of Its Onset 82 - Female Physiology Before Pregnancy and Female Hormones Physiologic Anatomy of the Female Sexual Organs Oogenesis and Follicular Development in the Ovaries Female Hormonal System Monthly Ovarian Cycle and Function of Gonadotropic Hormones Development of Antral and Vesicular Follicles. During the first few days of each monthly female sexual cycle, the concentrations... Ovulation A Surge of Luteinizing Hormone Is Necessary for Ovulation. LH is necessary for final follicular growth and ovulation. Without th... Initiation of Ovulation. Figure 82-6 provides a schema for the initiation of ovulation, showing the role of the large quantity ... Luteinizing Function of Luteinizing Hormone. The change of granulosa and theca interna cells into lutein cells depends mainly on... Secretion by the Corpus Luteum: An Additional Function of Luteinizing Hormone. The corpus luteum is a highly secretory organ, se... Involution of the Corpus Luteum and Onset of the Next Ovarian Cycle. Estrogen in particular and progesterone to a lesser extent,... Summary Functions of Ovarian Hormones—Estradiol and Progesterone Chemistry of the Sex Hormones Estrogens. In the normal nonpregnant female, estrogens are secreted in significant quantities only by the ovaries, although minu... Progestins. By far the most important of the progestins is progesterone. However, small amounts of another progestin, 17α-hydro... Synthesis of the Estrogens and Progestins. Note from the chemical formulas of the estrogens and progesterone in Figure 82-7 tha... Estrogens and Progesterone Are Transported in the Blood Bound to Plasma Proteins. Both estrogens and progesterone are transporte... Functions of the Liver in Estrogen Degradation. The liver conjugates estrogens to form glucuronides and sulfates, and about one-... Fate of Progesterone. Within a few minutes after secretion, almost all the progesterone is degraded to other steroids that have ... Effect of Estrogens on the Uterus and External Female Sex Organs. During childhood, estrogens are secreted only in minute quanti... Effect of Estrogens on the Fallopian Tubes. The estrogens’ effects on the mucosal lining of the fallopian tubes are similar to t... Effect of Estrogens on the Breasts. The primordial breasts of females and males are exactly alike. In fact, under the influence ... Effect of Estrogens on the Skeleton. Estrogens inhibit osteoclastic activity in the bones and therefore stimulate bone growth. A... Osteoporosis of the Bones Caused by Estrogen Deficiency in Old Age. After menopause, almost no estrogens are secreted by the ova... Estrogens Slightly Increase Protein Deposition. Estrogens cause a slight increase in total body protein, which is evidenced by a... Estrogens Increase Body Metabolism and Fat Deposition. Estrogens increase the whole-body metabolic rate slightly, but only abou... Estrogens Have Little Effect on Hair Distribution. Estrogens do not greatly affect hair distribution. However, hair does develop... Effect of Estrogens on the Skin. Estrogens cause the skin to develop a texture that is soft and usually smooth, but even so, the... Effect of Estrogens on Electrolyte Balance. The chemical similarity of estrogenic hormones to adrenocortical hormones has been d... Functions of Progesterone Progesterone Promotes Secretory Changes in the Uterus. A major function of progesterone is to promote secretory changes in the u... Progesterone Promotes Secretion by the Fallopian Tubes. Progesterone also promotes increased secretion by the mucosal lining of ... Progesterone Promotes Development of the Breasts. Progesterone promotes development of the lobules and alveoli of the breasts, c... Proliferative Phase (Estrogen Phase) of the Endometrial Cycle Occurs Before Ovulation. At the beginning of each monthly cycle, m... Secretory Phase (Progestational Phase) of the Endometrial Cycle Occurs After Ovulation. During most of the latter half of the mo... Menstruation. If the ovum is not fertilized, about 2 days before the end of the monthly cycle, the corpus luteum in the ovary in... Leukorrhea During Menstruation. During menstruation, large numbers of leukocytes are released, along with the necrotic material ... Regulation of Female Monthly Rhythm—Interplay Between Ovarian and Hypothalamic-Pituitary Hormones Intermittent, Pulsatile Secretion of GnRH by the Hypothalamus Stimulates Pulsatile Release of LH From the Anterior Pituitary Gla... Hypothalamic Centers for Release of Gonadotropin-Releasing Hormone. The neuronal activity that causes pulsatile release of GnRH... Inhibin From the Corpus Luteum Inhibits FSH and LH Secretion. In addition to the feedback effects of estrogen and progesterone, ... Anovulatory Cycles—Sexual Cycles at Puberty Puberty and Menarche Menopause Female Sexual Act Stimulation of the Female Sexual Act. As is true in the male sexual act, successful performance of the female sexual act depends... Female Erection and Lubrication. Located around the introitus and extending into the clitoris is erectile tissue almost identica... Female Orgasm. When local sexual stimulation reaches maximum intensity, and especially when the local sensations are supported b... 83 - Pregnancy and Lactation Maturation and Fertilization of the Ovum Entry of the Ovum Into the Fallopian Tube (Uterine Tube). When ovulation occurs, the ovum, along with a hundred or more attached... Early Nutrition of the Embryo Anatomy and Function of the Placenta Diffusion of Oxygen Through the Placental Membrane. Almost the same principles for diffusion of oxygen through the pulmonary mem... Diffusion of Carbon Dioxide Through the Placental Membrane. Carbon dioxide is continually formed in the fetal tissues in the sam... Diffusion of Foodstuffs Through the Placental Membrane. Other metabolic substrates needed by the fetus diffuse into the fetal bl... Excretion of Waste Products Through the Placental Membrane. In the same manner that carbon dioxide diffuses from the fetal blood... Hormonal Factors in Pregnancy Function of Human Chorionic Gonadotropin. Human chorionic gonadotropin is a glycoprotein having a molecular weight of about 39,0... Human Chorionic Gonadotropin Stimulates the Male Fetal Testes to Produce Testosterone. Human chorionic gonadotropin also exerts ... Function of Estrogen in Pregnancy. In Chapter 82, we pointed out that estrogens exert mainly a proliferative function on most re... Parturition Increased Uterine Excitability Near Term Hormonal Factors That Increase Uterine Contractility Increased Ratio of Estrogens to Progesterone. Progesterone inhibits uterine contractility during pregnancy, thereby helping to p... Oxytocin Causes Contraction of the Uterus. Oxytocin, a hormone secreted by the neurohypophysis, specifically causes uterine cont... Effect of Fetal Hormones on the Uterus. The fetus’s pituitary gland secretes increasing quantities of oxytocin, which might play... Stretch or Irritation of the Cervix. There is reason to believe that stretching or irritating the uterine cervix is particularly... Lactation Development of the Breasts Estrogens Stimulate Growth of the Ductal System of the Breasts. All through pregnancy, the large quantities of estrogens secrete... Progesterone Is Required for Full Development of the Lobule-Alveolar System. Final development of the breasts into milk-secret... Prolactin Promotes Lactation The Hypothalamus Secretes Prolactin Inhibitory Hormone. The hypothalamus plays an essential role in controlling prolactin secret... Suppression of the Female Ovarian Cycles in Nursing Mothers for Many Months After Delivery. In most nursing mothers, the ovarian... Inhibition of Milk Ejection. A particular problem in nursing a baby comes from the fact that many psychogenic factors or even ge... Antibodies and Other Anti-infectious Agents in Milk. Not only does milk provide the newborn baby with needed nutrients, but it ... 84 - Fetal and Neonatal Physiology 85 - Sports Physiology Normal Values for Selected Common Laboratory Measurements
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