Cardiovascular Physiology gives you a solid understanding of how the cardiovascular system functions in both health and disease. Ideal for your systems-based curriculum, this title in the Mosby Physiology Monograph Series explains how the latest concepts apply to real-life clinical situations.
Get clear, accurate, and up-to-the-minute coverage of the physiology of the cardiovascular system.
Master the material easily with objectives at the start of each chapter; self-study questions, summaries, and key words and concepts; and a multiple-choice review exam to help prep for USMLEs.
Grasp the latest concepts in vascular, molecular, and cellular biology as they apply to cardiovascular function, thanks to molecular commentaries in each chapter.
Apply information to clinical situations with the aid of clinical commentaries and highlighted clinical vignettes throughout.
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vii CON T E N T S C H A P T E R 1 OVERVIEW OF THE CIRCULATION AND BLOOD 1 The Circulatory System 1 Blood 5 Erythrocytes 5 Leukocytes 6 Lymphocytes 7 Blood Is Divided into Groups by Antigens Located on Erythrocytes 7 Summary 9 Case 1-1 9 C H A P T E R 2 EXCITATION: THE CARDIAC ACTION POTENTIAL . 11 Cardiac Action Potentials Consist of Several Phases 11 The Principal Types of Cardiac Action Potentials Are the Slow and Fast Types 12 Ionic Basis of the Resting Potential 13 The Fast Response Depends Mainly on Voltage-Dependent Sodium Channels 15 Ionic Basis of the Slow Response 24 Conduction in Cardiac Fibers Depends on Local Circuit Currents 25 Conduction of the Fast Response 25 Conduction of the Slow Response 27 Cardiac Excitability Depends on the Activation and Inactivation of Specific Currents 27 Fast Response 27 Slow Response 28 Effects of Cycle Length 28 Summary 29 Case 2-1 29 C H A P T E R 3 AUTOMATICITY: NATURAL EXCITATION OF THE HEART . 31 The Heart Generates Its Own Pacemaking Activity 31 Sinoatrial Node 32 Ionic Basis of Automaticity 34 Overdrive Suppression 35 Atrial Conduction 36 Atrioventricular Conduction 37 Ventricular Conduction 39 An Impulse Can Travel Around a Reentry Loop 41 Afterdepolarizations Lead to Triggered Activity 42 Early Afterdepolarizations 43 Delayed Afterdepolarizations 43 Electrocardiography Displays the Spread of Cardiac Excitation 44 Scalar Electrocardiography 44 Dysrhythmias Occur Frequently and Constitute Important Clinical Problems 47 Altered Sinoatrial Rhythms 47 Atrioventricular Transmission Blocks 48 Premature Depolarizations 48 Ectopic Tachycardias 49 Fibrillation 49 Summary 51 Case 3-3 52 C H A P T E R 4 THE CARDIAC PUMP 55 The Gross and Microscopic Structures of the Heart Are Uniquely Designed for Optimal Function 55 The Myocardial Cell 55 Structure of the Heart: Atria, Ventricles, and Valves 60 The Force of Cardiac Contraction Is Determined by Excitation-Contraction Coupling and the Initial Sarcomere Length of the Myocardial Cells 63 Excitation-Contraction Coupling Is Mediated by Calcium 63 Mechanics of Cardiac Muscle 65 The Sequential Contraction and Relaxation of the Atria and Ventricles Constitute the Cardiac Cycle 69 Ventricular Systole 70 Echocardiography Reveals Movement of the Ventricular Walls and of the Valves 73 The Two Major Heart Sounds Are Produced Mainly by Closure of the Cardiac Valves 74 The Pressure-Volume Relationships in the Intact Heart 75 Passive or Diastolic Pressure-Volume Relationship 75 Active or End-Systolic Pressure-Volume Relationship 77 Pressure and Volume during the Cardiac Cycle: The P-V Loop 77 Preload and Afterload during the Cardiac Cycle 77 Contractility 78 The Fick Principle Is Used to Determine Cardiac Output 79 Summary 89 Case 4-1 90 C H A P T E R 5 REGULATION OF THE HEARTBEAT 91 Heart Rate is Controlled Mainly by the Autonomic Nerves 91 Parasympathetic Pathways 92 Sympathetic Pathways 93 Higher Centers Also Influence Cardiac Performance 97 Heart Rate Can Be Regulated via the Baroreceptor Reflex 97 The Bainbridge Reflex and Atrial Receptors Regulate Heart Rate 98 Respiration Induces a Common Cardiac Dysrhythmia 99 Activation of the Chemoreceptor Reflex Affects Heart Rate 101 Ventricular Receptor Reflexes Play a Minor Role in the Regulation of Heart Rate 102 Myocardial Performance Is Regulated by Intrinsic Mechanisms 102 The Frank-Starling Mechanism Is an Important Regulator of Myocardial Contraction Force 103 Changes in Heart Rate Affect Contractile Force 107 Myocardial Performance Is Regulated by Nervous and Humoral Factors 110 Nervous Control 110 Cardiac Performance Is Also Regulated by Hormonal Substances 113 Summary 116 Case 5-1 117 C H A P T E R 6 HEMODYNAMICS 119 Velocity of the Bloodstream Depends on Blood Flow and Vascular Area 119 Blood Flow Depends on the Pressure Gradient 120 Relationship Between Pressure and Flow Depends on the Characteristics of the Conduits 122 Resistance to Flow 125 Resistances in Series and in Parallel 126 Flow May Be Laminar or Turbulent 127 Shear Stress on the Vessel Wall 128 Rheologic Properties of Blood 129 Summary 133 Case 6-6 134 C H A P T E R 7 THE ARTERIAL SYSTEM . 135 The Hydraulic Filter Converts Pulsatile Flow to Steady Flow 135 Arterial Elasticity Compensates for the Intermittent Flow Delivered by the Heart 137 The Arterial Blood Pressure Is Determined by Physical and Physiological Factors 140 Mean Arterial Pressure 140 Cardiac Output 142 Peripheral Resistance 142 Pulse Pressure 144 Stroke Volume 144 Arterial Compliance 145 Total Peripheral Resistance and Arterial Diastolic Pressure 146 The Pressure Curves Change in Arteries at Different Distances from the Heart 147 Blood Pressure Is Measured by a Sphygmomanometer in Human Patients 148 Summary 150 Case 7-1 150 C H A P T E R 8 THE MICROCIRCULATION AND LYMPHATICS. 153 Functional Anatomy 153 Arterioles Are the Stopcocks of the Circulation 153 Capillaries Permit the Exchange of Water, Solutes, and Gases 154 The Law of Laplace Explains How Capillaries Can Withstand High Intravascular Pressures 155 The Endothelium Plays an Active Role in Regulating the Microcirculation 156 The Endothelium is at the Center of Flow- Initiated Mechanotransduction 157 The Endothelium Plays a Passive Role in Transcapillary Exchange 158 Diffusion Is the Most Important Means of Water and Solute Transfer Across the Endothelium 159 Diffusion of Lipid-Insoluble Molecules Is Restricted to the Pores 159 Lipid-Soluble Molecules Pass Directly Through the Lipid Membranes of the Endothelium and the Pores 162 Capillary Filtration Is Regulated by the Hydrostatic and Osmotic Forces Across the Endothelium 163 Balance of Hydrostatic and Osmotic Forces 165 The Capillary Filtration Coefficient Provides a Method to Estimate the Rate of Fluid Movement Across the Endothelium 165 Pinocytosis Enables Large Molecules to Cross the Endothelium 167 The Lymphatics Return the Fluid and Solutes That Escape Through the Endothelium to the Circulating Blood 167 Summary 168 Case 8-1 169 Case 8-2 169 C H A P T E R 9 THE PERIPHERAL CIRCULATION AND ITS CONTROL 171 The Functions of the Heart and Large Blood Vessels 171 Contraction and Relaxation of Arteriolar Vascular Smooth Muscle Regulate Peripheral Blood Flow 172 Cytoplasmic Ca++ Is Regulated to Control Contraction, via MLCK 175 Contraction Is Controlled by Excitation- Contraction Coupling and/or Pharmacomechanical Coupling 176 Control of Vascular Tone by Catecholamines 178 Control of Vascular Contraction by Other Hormones, Other Neurotransmitters, and Autocoids 178 Intrinsic Control of Peripheral Blood Flow 179 Autoregulation and the Myogenic Mechanism Tend to Keep Blood Flow Constant 179 The Endothelium Actively Regulates Blood Flow 180 Tissue Metabolic Activity Is the Main Factor in the Local Regulation of Blood Flow 181 Extrinsic Control of Peripheral Blood Flow Is Mediated Mainly by the Sympathetic Nervous System 183 Impulses That Arise in the Medulla Descend in the Sympathetic Nerves to Increase Vascular Resistance 183 Sympathetic Nerves Regulate the Contractile State of the Resistance and Capacitance Vessels 184 The Parasympathetic Nervous System Innervates Blood Vessels Only in the Cranial and Sacral Regions of the Body 185 Epinephrine and Norepinephrine Are the Main Humoral Factors That Affect Vascular Resistance 185 The Vascular Reflexes Are Responsible for Rapid Adjustments of Blood Pressure 185 The Peripheral Chemoreceptors Are Stimulated by Decreases in Blood Oxygen Tension and pH and by Increases in Carbon Dioxide Tension 189 The Central Chemoreceptors Are Sensitive to Changes in Paco2 189 Other Vascular Reflexes 190 Balance Between Extrinsic and Intrinsic Factors in Regulation of Peripheral Blood Flow 191 Summary 192 Case 9-1 194 C H A P T E R 10 CONTROL OF CARDIAC OUTPUT: COUPLING OF HEART AND BLOOD VESSELS . 195 Factors Controlling Cardiac Output 195 The Cardiac Function Curve Relates Central Venous Pressure (Preload) to Cardiac Output 196 Preload or Filling Pressure of the Heart 196 Cardiac Function Curve 196 Factors That Change the Cardiac Function Curve 197 The Vascular Function Curve Relates Central Venous Pressure to Cardiac Output 200 Mathematical Analysis of the Vascular Function Curve 203 Venous Pressure Depends on Cardiac Output 205 Blood Volume 205 Venomotor Tone 206 Blood Reservoirs 206 Peripheral Resistance 206 Cardiac Output and Venous Return Are Closely Associated 207 The Heart and Vasculature Are Coupled Functionally 207 Myocardial Contractility 209 Blood Volume 209 Peripheral Resistance 210 The Right Ventricle Regulates Not Only Pulmonary Blood Flow but Also Central Venous Pressure 211 Heart Rate Has Ambivalent Effects on Cardiac Output 214 Ancillary Factors Affect the Venous System and Cardiac Output 216 Gravity 216 Muscular Activity and Venous Valves 218 Respiratory Activity 219 Artificial Respiration 220 Summary 221 Case 10-1 221 C H A P T E R 11 CORONARY CIRCULATION . 223 Functional Anatomy of the Coronary Vessels 223 Coronary Blood Flow Is Regulated by Physical, Neural, and Metabolic Factors 225 Physical Factors 225 Neural and Neurohumoral Factors 227 Metabolic Factors 228 Diminished Coronary Blood Flow Impairs Cardiac Function 230 Energy Substrate Metabolism During Ischemia 231 Coronary Collateral Vessels Develop in Response to Impairment of Coronary Blood Flow 233 Summary 235 Case 11-1 236 C H A P T E R 12 SPECIAL CIRCULATIONS 237 Cutaneous Circulation 237 Skin Blood Flow Is Regulated Mainly by the Sympathetic Nervous System 237 Ambient Temperature and Body Temperature Play Important Roles in the Regulation of Skin Blood Flow 239 Skin Color Depends on the Volume and Flow of Blood in the Skin and on the Amount of O2 Bound to Hemoglobin 240 Skeletal Muscle Circulation 240 Regulation of Skeletal Muscle Circulation 240 Cerebral Circulation 243 Local Factors Predominate in the Regulation of Cerebral Blood Flow 243 The Pulmonary and Systemic Circulations Are in Series with Each Other 245 Functional Anatomy 245 Pulmonary Hemodynamics 247 Regulation of the Pulmonary Circulation 249 The Renal Circulation Affects the Cardiac Output 250 Anatomy 250 Renal Hemodynamics 252 The Renal Circulation Is Regulated by Intrinsic Mechanisms 252 The Splanchnic Circulation Provides Blood Flow to the Gastrointestinal Tract, Liver, Spleen, and Pancreas 254 Intestinal Circulation 254 Hepatic Circulation 256 Fetal Circulation 257 Changes in the Circulatory System at Birth 259 Summary 260 Case 12-1 262 Case 12-2 262 Case 12-3 262 C H A P T E R 13 INTERPLAY OF CENTRAL AND PERIPHERAL FACTORS THAT CONTROL THE CIRCULATION 263 Exercise 264 Mild to Moderate Exercise 264 Severe Exercise 268 Postexercise Recovery 268 Limits of Exercise Performance 269 Physical Training and Conditioning 269 Hemorrhage 269 Hemorrhage Evokes Compensatory and Decompensatory Effects on the Arterial Blood Pressure 270 The Compensatory Mechanisms Are Neural and Humoral 270 The Decompensatory Mechanisms Are Mainly Humoral, Cardiac, and Hematologic 273 The Positive and Negative Feedback Mechanisms Interact 275 Summary 276 Case 13-1 277 Case 13-2 277 APPENDIX: CASE STUDY ANSWERS . 279