Cardiovascular Physiology

Chapter 1 OVERVIEW OF THE CIRCULATION AND BLOOD The Circulatory System Blood Erythrocytes Leukocytes Lymphocytes Platelets Blood Is Divided into Groups by Antigens Located on Erythrocytes Summary Case 1-1 Chapter 2 EXCITATION: THE CARDIAC ACTION POTENTIAL Cardiac Action Potentials Consist of Several Phases The Principal Types of Cardiac Action Potentials Are the Slow and Fast Types Ionic Basis of the Resting Potential The Fast Response Depends Mainly on Voltage-Dependent Sodium Channels Ionic Basis of the Slow Response Conduction in Cardiac Fibers Depends on Local Circuit Currents Conduction of the Fast Response Conduction of the Slow Response Cardiac Excitability Depends on the Activation and Inactivation of Specific Currents Fast Response Slow Response Effects of Cycle Length Summary Case 2-1 Chapter 3 AUTOMATICITY: NATURAL EXCITATION OF THE HEART The Heart Generates Its Own Pacemaking Activity Sinoatrial Node Ionic Basis of Automaticity Overdrive Suppression Atrial Conduction Atrioventricular Conduction Ventricular Conduction An Impulse Can Travel Around a Reentry Loop Afterdepolarizations Lead to Triggered Activity Early Afterdepolarizations Delayed Afterdepolarizations Electrocardiography Displays the Spread of Cardiac Excitation Scalar Electrocardiography Dysrhythmias Occur Frequently and Constitute Important Clinical Problems Altered Sinoatrial Rhythms Atrioventricular Transmission Blocks Premature Depolarizations Ectopic Tachycardias Fibrillation Summary Case 3-1 Chapter 4 THE CARDIAC PUMP The Microscopic and Gross Structures of the Heart Cardiac Muscle (myocardial) Cell Morphology Structure of the Heart: Atria, Ventricles, and Valves The Force of Cardiac Contraction Is Determined by Excitation-Contraction Coupling and the Initial Sarcomere Length of the Myocardial Cells Excitation-Contraction Coupling Is Mediated by Calcium Mechanics of Cardiac Muscle The Sequential Contraction and Relaxation of the Atria and Ventricles Constitute the Cardiac Cycle Ventricular Systole Echocardiography Reveals Movement of the Ventricular Walls and of the Valves The Two Major Heart Sounds Are Produced Mainly by Closure of the Cardiac Valves The Pressure-Volume Relationships in the Intact Heart Passive or Diastolic Pressure-Volume Relationship Active or End-Systolic Pressure-Volume Relationship Pressure and Volume during the Cardiac Cycle: The P-V Loop Preload and Afterload during the Cardiac Cycle Contractility The Fick Principle Is Used to Determine Cardiac Output Metabolism of ATP and its Relation to Mechanical Function Fatty Acid Metabolism Carbohydrate Metabolism Interrelation between Fatty Acid and Carbohydrate Metabolism Effects of plasma substrate and insulin levels Cardiac O2 Consumption and the Link between Ventricular Function and Cardiac Metabolism Summary Case 4-1 Chapter 5 REGULATION OF THE HEARTBEAT Heart Rate is Controlled Mainly by the Autonomic Nerves Parasympathetic Pathways Sympathetic Pathways Higher Centers Also Influence Cardiac Performance Heart Rate Can Be Regulated via the Baroreceptor Reflex The Bainbridge Reflex and Atrial Receptors Regulate Heart Rate Respiration Induces a Common Cardiac Dysrhythmia Activation of the Chemoreceptor Reflex Affects Heart Rate Ventricular Receptor Reflexes Play a Minor Role in the Regulation of Heart Rate Myocardial Performance Is Regulated by Intrinsic Mechanisms The Frank-Starling Mechanism Is an Important Regulator of Myocardial Contraction Force Changes in Heart Rate Affect Contractile Force Myocardial Performance Is Regulated by Nervous and Humoral Factors Nervous Control Cardiac Performance Is Also Regulated by Hormonal Substances Summary Case 5-1 Chapter 6 HEMODYNAMICS Velocity of the Bloodstream Depends on Blood Flow and Vascular Area Blood Flow Depends on the Pressure Gradient Relationship Between Pressure and Flow Depends on the Characteristics of the Conduits Resistance to Flow Resistances in Series and in Parallel Flow May Be Laminar or Turbulent Shear Stress on the Vessel Wall Rheologic Properties of Blood Summary Case 6-1 Chapter 7 THE ARTERIAL SYSTEM The Hydraulic Filter Converts Pulsatile Flow to Steady Flow Arterial Elasticity Compensates for the Intermittent Flow Delivered by the Heart The Arterial Blood Pressure Is Determined by Physical and Physiological Factors Mean Arterial Pressure Cardiac Output Peripheral Resistance Pulse Pressure Stroke Volume Arterial Compliance Total Peripheral Resistance and Arterial Diastolic Pressure The Pressure Curves Change in Arteries at Different Distances from the Heart Blood Pressure Is Measured by a Sphygmomanometer in Human Patients Summary Case 7-1 Chapter 8 The MICROCIRCULATION AND LYMPHATICS Functional Anatomy Arterioles Are the Stopcocks of the Circulation Capillaries Permit the Exchange of Water, Solutes, and Gases The Law of Laplace Explains How Capillaries Can Withstand High Intravascular Pressures The Endothelium Plays an Active Role in Regulating the Microcirculation The Endothelium is at the Center of Flow-Initiated Mechanotransduction The Endothelium Plays a Passive Role in Transcapillary Exchange Diffusion Is the Most Important Means of Water and Solute Transfer Across the Endothelium Diffusion of Lipid-Insoluble Molecules Is Restricted to the Pores Lipid-Soluble Molecules Pass Directly Through the Lipid Membranes of the Endothelium and the Pores Capillary Filtration Is Regulated by the Hydrostatic and Osmotic Forces Across the Endothelium Balance of Hydrostatic and Osmotic Forces The Capillary Filtration Coefficient Provides a Method to Estimate the Rate of Fluid Movement Across the Endothelium Hypoxia-inducible factor(s) and angiogenesis Pinocytosis Enables Large Molecules to Cross the Endothelium The Lymphatics Return the Fluid and Solutes That Escape Through the Endothelium to the Circulating Blood Summary Case 8-1 Case 8-2 Chapter 9 The PERIPHERAL CIRCULATION AND ITS CONTROL The Functions of the Heart and Large Blood Vessels Contraction and Relaxation of Arteriolar Vascular Smooth Muscle Regulate Peripheral Blood Flow Cytoplasmic Ca++ Is Regulated to Control Contraction, via MLCK Contraction Is Controlled by Excitation-Contraction Coupling and/or Pharmacomechanical Coupling Control of Vascular Tone by Catecholamines Control of Vascular Contraction by Other Hormones, Other Neurotransmitters, and Autocoids Intrinsic Control of Peripheral Blood Flow Autoregulation and the Myogenic Mechanism Tend to Keep Blood Flow Constant The Endothelium Actively Regulates Blood Flow Tissue Metabolic Activity Is the Main Factor in the Local Regulation of Blood Flow Extrinsic Control of Peripheral Blood Flow Is Mediated Mainly by the Sympathetic Nervous System Impulses That Arise in the Medulla Descend in the Sympathetic Nerves to Increase Vascular Resistance Sympathetic Nerves Regulate the Contractile State of the Resistance and Capacitance Vessels The Parasympathetic Nervous System Innervates Blood Vessels Only in the Cranial and Sacral Regions of the Body Epinephrine and Norepinephrine Are the Main Humoral Factors That Affect Vascular Resistance The Vascular Reflexes Are Responsible for Rapid Adjustments of Blood Pressure The Peripheral Chemoreceptors Are Stimulated by Decreases in Blood Oxygen Tension and pH and by Increases in Carbon Dioxide Tension The Central Chemoreceptors Are Sensitive to Changes in Paco2 Other Vascular Reflexes Balance Between Extrinsic and Intrinsic Factors in Regulation of Peripheral Blood Flow Summary Case 9-1 Chapter 10 CONTROL OF CARDIAC OUTPUT: COUPLING OF HEART AND BLOOD VESSELS Factors Controlling Cardiac Output The Cardiac Function Curve Relates Central Venous Pressure (Preload) to Cardiac Output Preload or Filling Pressure of the Heart Cardiac Function Curve Factors That Change the Cardiac Function Curve The Vascular Function Curve Relates Central Venous Pressure to Cardiac Output Mathematical Analysis of the Vascular Function Curve Venous Pressure Depends on Cardiac Output Blood Volume Venomotor Tone Blood Reservoirs Peripheral Resistance Cardiac Output and Venous Return Are Closely Associated The Heart and Vasculature Are Coupled Functionally Myocardial Contractility Blood Volume Peripheral Resistance The Right Ventricle Regulates Not Only Pulmonary Blood Flow but Also Central Venous Pressure Heart Rate Has Ambivalent Effects on Cardiac Output Ancillary Factors Affect the Venous System and Cardiac Output Gravity Muscular Activity and Venous Valves Respiratory Activity Artificial Respiration Summary Case 10-1 Chapter 11 CORONARY CIRCULATION Functional Anatomy of the Coronary Vessels Coronary Blood Flow Is Regulated by Physical, Neural, and Metabolic Factors Physical Factors Neural and Neurohumoral Factors Metabolic Factors Diminished Coronary Blood Flow Impairs Cardiac Function Energy Substrate Metabolism During Ischemia Coronary Collateral Vessels Develop in Response to Impairment of Coronary Blood Flow Summary Case 11-1 Chapter 12 SPECIAL CIRCULATIONS Cutaneous Circulation Skin Blood Flow Is Regulated Mainly by the Sympathetic Nervous System Ambient Temperature and Body Temperature Play Important Roles in the Regulation of Skin Blood Flow Skin Color Depends on the Volume and Flow of Blood in the Skin and on the Amount of O2 Bound to Hemoglobin Skeletal Muscle Circulation Regulation of Skeletal Muscle Circulation Cerebral Circulation Local Factors Predominate in the Regulation of Cerebral Blood Flow The Pulmonary and Systemic Circulations Are in Series with Each Other Functional Anatomy Pulmonary Hemodynamics Regulation of the Pulmonary Circulation The Renal Circulation Affects the Cardiac Output Anatomy Renal Hemodynamics The Renal Circulation Is Regulated by Intrinsic Mechanisms The Splanchnic Circulation Provides Blood Flow to the Gastrointestinal Tract, Liver, Spleen, and Pancreas Intestinal Circulation Hepatic Circulation Fetal Circulation Changes in the Circulatory System at Birth Summary Case 12-1 Case 12-2 Case 12-3 Chapter 13 INTERPLAY OF CENTRAL AND PERIPHERAL FACTORS THAT CONTROL THE CIRCULATION Exercise Mild to Moderate Exercise Severe Exercise Postexercise Recovery Limits of Exercise Performance Physical Training and Conditioning Hemorrhage Hemorrhage Evokes Compensatory and Decompensatory Effects on the Arterial Blood Pressure The Compensatory Mechanisms Are Neural and Humoral The Decompensatory Mechanisms Are Mainly Humoral, Cardiac, and Hematologic The Positive and Negative Feedback Mechanisms Interact Summary Case 13-1 Case 13-2 Appendix A: End-of-Chapter CASE STUDY ANSWERS Appendix B: Comprehensive Examination