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| Overview of the Circulation and Blood | |
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| The Circulatory System | |
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| Blood | |
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| Erythrocytes | |
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| Leukocytes | |
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| Lymphocytes | |
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| Blood Is Divided into Groups by Antigens Located on Erythrocytes | |
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| Summary | |
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| Case 1-1 | |
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| Excitation: The Cardiac Action Potential | |
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| Cardiac Action Potentials Consist of Several Phases | |
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| The Principal Types of Cardiac Action Potentials Are the Slow and Fast Types | |
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| Ionic Basis of the Resting Potential | |
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| The Fast Response Depends Mainly on Voltage-Dependent Sodium Channels | |
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| Ionic Basis of the Slow Response | |
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| Conduction in Cardiac Fibers Depends on Local Circuit Currents | |
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| Conduction of the Fast Response | |
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| Conduction of the Slow Response | |
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| Cardiac Excitability Depends on the Activation and Inactivation of Specific Currents | |
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| Fast Response | |
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| Slow Response | |
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| Effects of Cycle Length | |
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| Summary | |
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| Case 2-1 | |
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| Automaticity: Natural Excitation of the Heart | |
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| The Heart Generates Its Own Pacemaking Activity | |
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| Sinoatrial Node | |
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| Ionic Basis of Automaticity | |
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| Overdrive Suppression | |
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| Atrial Conduction | |
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| Atrioventricular Conduction | |
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| Ventricular Conduction | |
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| An Impulse Can Travel Around a Reentry Loop | |
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| Afterdepolarizations Lead to Triggered Activity | |
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| Early Afterdepolarizations | |
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| Delayed Afterdepolarizations | |
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| Electrocardiography Displays the Spread of Cardiac Excitation | |
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| Scalar Electrocardiography | |
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| Dysrhythmias Occur Frequently and Constitute Important Clinical Problems | |
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| Altered Sinoatrial Rhythms | |
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| Atrioventricular Transmission Blocks | |
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| Premature Depolarizations | |
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| Ectopic Tachycardias | |
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| Fibrillation | |
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| Summary | |
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| Case 3-3 | |
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| The Cardiac Pump | |
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| The Gross and Microscopic Structures of the Heart Are Uniquely Designed for Optimal Function | |
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| The Myocardial Cell | |
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| Structure of the Heart: Atria, Ventricles, and Valves | |
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| The Force of Cardiac Contraction Is Determined by Excitation-Contraction Coupling and the Initial Sarcomere Length of the Myocardial Cells | |
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| Excitation-Contraction Coupling Is Mediated by Calcium | |
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| Mechanics of Cardiac Muscle | |
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| The Sequential Contraction and Relaxation of the Atria and Ventricles Constitute the Cardiac Cycle | |
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| Ventricular Systole | |
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| Echocardiography Reveals Movement of the Ventricular Walls and of the Valves | |
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| The Two Major Heart Sounds Are Produced Mainly by Closure of the Cardiac Valves | |
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| The Pressure-Volume Relationships in the Intact Heart | |
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| Passive or Diastolic Pressure-Volume Relationship | |
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| Active or End-Systolic Pressure-Volume Relationship | |
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| Pressure and Volume during the Cardiac Cycle: The P-V Loop | |
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| Preload and Afterload during the Cardiac Cycle | |
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| Contractility | |
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| The Fick Principle Is Used to Determine Cardiac Output | |
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| Summary | |
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| Case 4-1 | |
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| Regulation of the Heartbeat | |
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| Heart Rate is Controlled Mainly by the Autonomic Nerves | |
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| Parasympathetic Pathways | |
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| Sympathetic Pathways | |
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| Higher Centers Also Influence Cardiac Performance | |
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| Heart Rate Can Be Regulated via the Baroreceptor Reflex | |
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| The Bainbridge Reflex and Atrial Receptors Regulate Heart Rate | |
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| Respiration Induces a Common Cardiac Dysrhythmia | |
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| Activation of the Chemoreceptor Reflex Affects Heart Rate | |
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| Ventricular Receptor Reflexes Play a Minor Role in the Regulation of Heart Rate | |
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| Myocardial Performance Is Regulated by Intrinsic Mechanisms | |
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| The Frank-Starling Mechanism Is an Important Regulator of Myocardial Contraction Force | |
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| Changes in Heart Rate Affect Contractile Force | |
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| Myocardial Performance Is Regulated by Nervous and Humoral Factors | |
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| Nervous Control | |
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| Cardiac Performance Is Also Regulated by Hormonal Substances | |
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| Summary | |
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| Case 5-1 | |
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| Hemodynamics | |
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| Velocity of the Bloodstream Depends on Blood Flow and Vascular Area | |
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| Blood Flow Depends on the Pressure Gradient | |
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| Relationship Between Pressure and Flow Depends on the Characteristics of the Conduits | |
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| Resistance to Flow | |
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| Resistances in Series and in Parallel | |
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| Flow May Be Laminar or Turbulent | |
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| Shear Stress on the Vessel Wall | |
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| Rheologic Properties of Blood | |
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| Summary | |
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| Case 6-6 | |
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| The Arterial System | |
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| The Hydraulic Filter Converts Pulsatile Flow to Steady Flow | |
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| Arterial Elasticity Compensates for the Intermittent Flow Delivered by the Heart | |
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| The Arterial Blood Pressure Is Determined by Physical and Physiological Factors | |
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| Mean Arterial Pressure | |
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| Cardiac Output | |
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| Peripheral Resistance | |
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| Pulse Pressure | |
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| Stroke Volume | |
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| Arterial Compliance | |
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| Total Peripheral Resistance and Arterial Diastolic Pressure | |
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| The Pressure Curves Change in Arteries at Different Distances from the Heart | |
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| Blood Pressure Is Measured by a Sphygmomanometer in Human Patients | |
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| Summary | |
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| Case 7-1 | |
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| The Microcirculation and Lymphatics | |
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| Functional Anatomy | |
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| Arterioles Are the Stopcocks of the Circulation | |
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| Capillaries Permit the Exchange of Water, Solutes, and Gases | |
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| The Law of Laplace Explains How Capillaries Can Withstand High Intravascular Pressures | |
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| The Endothelium Plays an Active Role in Regulating the Microcirculation | |
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| The Endothelium is at the Center of Flow-Initiated Mechanotransduction | |
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| The Endothelium Plays a Passive Role in Transcapillary Exchange | |
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| Diffusion Is the Most Important Means of Water and Solute Transfer Across the Endothelium | |
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| Diffusion of Lipid-Insoluble Molecules Is Restricted to the Pores | |
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| Lipid-Soluble Molecules Pass Directly Through the Lipid Membranes of the Endothelium and the Pores | |
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| Capillary Filtration Is Regulated by the Hydrostatic and Osmotic Forces Across the Endothelium | |
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| Balance of Hydrostatic and Osmotic Forces | |
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| The Capillary Filtration Coefficient Provides a Method to Estimate the Rate of Fluid Movement Across the Endothelium | |
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| Pinocytosis Enables Large Molecules to Cross the Endothelium | |
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| The Lymphatics Return the Fluid and Solutes That Escape Through the Endothelium to the Circulating Blood | |
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| Summary | |
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| Case 8-1 | |
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| Case 8-2 | |
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| The Peripheral Circulation and its Control | |
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| The Functions of the Heart and Large Blood Vessels | |
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| Contraction and Relaxation of Arteriolar Vascular Smooth Muscle Regulate Peripheral Blood Flow | |
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| Cytoplasmic Ca<sub>++</sub> Is Regulated to Control Contraction, via MLCK | |
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| Contraction Is Controlled by Excitation-Contraction Coupling and/or Pharmacomechanical Coupling | |
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| Control of Vascular Tone by Catecholamines | |
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| Control of Vascular Contraction by Other Hormones, Other Neurotransmitters, and Autocoids | |
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| Intrinsic Control of Peripheral Blood Flow | |
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| Autoregulation and the Myogenic Mechanism Tend to Keep Blood Flow Constant | |
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| The Endothelium Actively Regulates Blood Flow | |
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| Tissue Metabolic Activity Is the Main Factor in the Local Regulation of Blood Flow | |
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| Extrinsic Control of Peripheral Blood Flow Is Mediated Mainly by the Sympathetic Nervous System | |
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| Impulses That Arise in the Medulla Descend in the Sympathetic Nerves to Increase Vascular Resistance | |
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| Sympathetic Nerves Regulate the Contractile State of the Resistance and Capacitance Vessels | |
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| The Parasympathetic Nervous System Innervates Blood Vessels Only in the Cranial and Sacral Regions of the Body | |
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| Epinephrine and Norepinephrine Are the Main Humoral Factors That Affect Vascular Resistance | |
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| The Vascular Reflexes Are Responsible for Rapid Adjustments of Blood Pressure | |
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| The Peripheral Chemoreceptors Are Stimulated by Decreases in Blood Oxygen Tension and pH and by Increases in Carbon Dioxide Tension | |
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| The Central Chemoreceptors Are Sensitive to Changes in Paco<sub>2</sub> | |
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| Other Vascular Reflexes | |
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| Balance Between Extrinsic and Intrinsic Factors in Regulation of Peripheral Blood Flow | |
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| Summary | |
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| Case 9-1 | |
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| Control of Cardiac Output: Coupling of Heart and Blood Vessels | |
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| Factors Controlling Cardiac Output | |
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| The Cardiac Function Curve Relates Central Venous Pressure (Preload) to Cardiac Output | |
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| Preload or Filling Pressure of the Heart | |
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| Cardiac Function Curve | |
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| Factors That Change the Cardiac Function Curve | |
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| The Vascular Function Curve Relates Central Venous Pressure to Cardiac Output | |
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| Mathematical Analysis of the Vascular Function Curve | |
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| Venous Pressure Depends on Cardiac Output | |
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| Blood Volume | |
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| Venomotor Tone | |
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| Blood Reservoirs | |
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| Peripheral Resistance | |
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| Cardiac Output and Venous Return Are Closely Associated | |
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| The Heart and Vasculature Are Coupled Functionally | |
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| Myocardial Contractility | |
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| Blood Volume | |
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| Peripheral Resistance | |
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| The Right Ventricle Regulates Not Only Pulmonary Blood Flow but Also Central Venous Pressure | |
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| Heart Rate Has Ambivalent Effects on Cardiac Output | |
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| Ancillary Factors Affect the Venous System and Cardiac Output | |
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| Gravity | |
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| Muscular Activity and Venous Valves | |
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| Respiratory Activity | |
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| Artificial Respiration | |
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| Summary | |
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| Case 10-1 | |
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| Coronary Circulation | |
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| Functional Anatomy of the Coronary Vessels | |
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| Coronary Blood Flow Is Regulated by Physical, Neural, and Metabolic Factors | |
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| Physical Factors | |
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| Neural and Neurohumoral Factors | |
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| Metabolic Factors | |
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| Diminished Coronary Blood Flow Impairs Cardiac Function | |
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| Energy Substrate Metabolism During Ischemia | |
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| Coronary Collateral Vessels Develop in Response to Impairment of Coronary Blood Flow | |
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| Summary | |
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| Case 11-1 | |
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| Special Circulations | |
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| Cutaneous Circulation | |
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| Skin Blood Flow Is Regulated Mainly by the Sympathetic Nervous System | |
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| Ambient Temperature and Body Temperature Play Important Roles in the Regulation of Skin Blood Flow | |
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| Skin Color Depends on the Volume and Flow of Blood in the Skin and on the Amount of O<sub>2</sub> Bound to Hemoglobin | |
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| Skeletal Muscle Circulation | |
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| Regulation of Skeletal Muscle Circulation | |
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| Cerebral Circulation | |
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| Local Factors Predominate in the Regulation of Cerebral Blood Flow | |
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| The Pulmonary and Systemic Circulations Are in Series with Each Other | |
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| Functional Anatomy | |
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| Pulmonary Hemodynamics | |
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| Regulation of the Pulmonary Circulation | |
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| The Renal Circulation Affects the Cardiac Output | |
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| Anatomy | |
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| Renal Hemodynamics | |
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| The Renal Circulation Is Regulated by Intrinsic Mechanisms | |
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| The Splanchnic Circulation Provides Blood Flow to the Gastrointestinal Tract, Liver, Spleen, and Pancreas | |
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| Intestinal Circulation | |
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| Hepatic Circulation | |
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| Fetal Circulation | |
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| Changes in the Circulatory System at Birth | |
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| Summary | |
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| Case 12-1 | |
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| Case 12-2 | |
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| Case 12-3 | |
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| Interplay of Central and Peripheral Factors that Control the Circulation | |
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| Exercise | |
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| Mild to Moderate Exercise | |
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| Severe Exercise | |
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| Postexercise Recovery | |
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| Limits of Exercise Performance | |
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| Physical Training and Conditioning | |
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| Hemorrhage | |
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| Hemorrhage Evokes Compensatory and Decompensatory Effects on the Arterial Blood Pressure | |
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| The Compensatory Mechanisms Are Neural and Humoral | |
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| The Decompensatory Mechanisms Are Mainly Humoral, Cardiac, and Hematologic | |
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| The Positive and Negative Feedback Mechanisms Interact | |
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| Summary | |
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| Case 13-1 | |
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| Case 13-2 | |
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| Appendix: Case Study Answers | |