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The Cardiovascular System: Morphology, Control and Function

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Contents

Contributors

Abbreviations

Preface

Chapter 1: Heart Morphology and Anatomy

1. Introduction

2. Fish Heart Chambers: A Reassessment

3. Sequential Analysis of the Heart: A Comparative Approach

3.1. The Sinus Venosus

3.2. The Atrium

3.3. The AV Segment

3.4. The Ventricle

3.5. The Outflow Tract

3.5.1. Basal Gnathostomata

3.5.2. More Advanced Teleosts

3.5.2.1. The Conus Arteriosus and the Conus Valves

3.5.2.2. The Bulbus Arteriosus

4. Blood Supply to the Heart Chambers

5. Cardiac Nerves

6. The Heart's Pacemaker and Conduction System

7. Lungfish Heart: A Special Case

7.1. The Sinus Venosus

7.2. The Atrium, the AV Region and the Ventricle

7.3. The Outflow Tract

8. Summary and Future Directions

Acknowledgments

References

Chapter 2: Cardiomyocyte Morphology and Physiology

1. Introduction

2. Gross Myocyte Morphology

2.1. Sarcolemmal and Cell–Cell Interactions

2.1.1. Mechanical Connections Between Cells

2.1.2. Electrical Connections Between Cells

2.2. Mitochondria

3. Excitation–Contraction Coupling

3.1. Extracellular Ca2+ Influx

3.1.1. The L-Type Ca2+ Channel

3.1.2. The Na+–Ca2+ Exchanger

3.2. Intracellular Ca2+ Cycling and the SR

3.2.1. Ultrastructure Studies of the SR

3.2.2. Ryanodine Receptors

3.2.3. SR Ca2+ Content, SERCA, and Phospholamban

3.2.4. Ca2+-Induced Ca2+ Release

3.3. The Ca2+ Transient (Δ[Ca2+]i) and Myocardial Relaxation

4. β-Adrenergic Receptors

5. The Myofilaments

5.1. Myosin ATPase Activity

5.2. Ca2+ and Myofilament Contraction

5.3. The Frank Starling and Cellular Length–Tension Relationships

5.4. Myofilament Ca2+ Sensitivity and Length-Dependent Activation

6. Conclusions

References

Chapter 3: Electrical Excitability of the Fish Heart and Its Autonomic Regulation

1. Introduction

2. Electrical Excitability of the Fish Heart

3. Cardiac Action Potential

4. Rhythm of the Heartbeat and Impulse Conduction

5. Ion Currents of the Fish Heart

5.1. Inward Currents

5.1.1. Sodium Current (INa)

5.1.2. Calcium Currents (ICa)

5.1.2.1. L-type Ca2+ Current (ICaL)

5.1.2.2. T-type Ca2+ Current (ICaT)

5.1.2.3. The Hyperpolarization-Activated Funny Current (If)

5.2. Outward Potassium Currents

5.2.1. Voltage-Gated K+ Currents (IK)

5.2.1.1. The Rapid Component of the Delayed Rectifier (IKr)

5.2.1.2. The Slow Component of the Delayed Rectifier (IKs)

5.2.2. Inward Rectifier K+ Currents (IKir)

5.2.2.1. The Background Inward Rectifier Current (IK1)

5.2.2.2. Acetylcholine-Activated Inward Rectifier Current (IKACH)

5.2.2.3. ATP-Sensitive Potassium Current (IKATP)

6. Effects of Autonomic Nervous Control on Cardiac Excitability

6.1. Cholinergic Regulation of Nodal Tissues and the Atrium

6.2. Adrenergic Regulation

7. Significance of Ion Channel Function in Thermal Tolerance of Fish Hearts

7.1. Thermal Tolerance Limits of the Fish Heart in Comparison With Other Vertebrates

7.2. Are Fish Hearts Resistant to Temperature-Induced Arrhythmias?

7.3. Is Ion Channel Function Involved in the Heat Tolerance of Fish Heart Function?

8. Summary

References

Chapter 4: Cardiac Form, Function and Physiology

1. Introduction

2. Cardiac Form and Function

2.1. Sinus Venosus

2.2. Atrium

2.3. Ventricle

2.4. Cardiac Outflow Tract

2.5. Coronary Circulation

3. Cardiac Physiology

3.1. The Cardiac Cycle

3.2. Cardiac Output

3.2.1. Measuring Cardiac Function in Fishes

3.2.2. Species Differences in Routine Cardiac Output

3.2.3. Responses of Cardiac Output to Swimming

3.2.4. Response of Cardiac Output to Changes in Temperature

3.2.5. Response of Cardiac Output to Hypoxia and Anoxia

3.2.6. Response of Cardiac Output to Extracellular Acidosis

3.2.7. Responses of Cardiac Output to Feeding

4. Heart Rate and Its Control

4.1. Intrinsic Heart Rate

4.1.1. Regulation of the Intrinsic Heart Rate

4.2. Cardiac Innervation and the Intracardiac Nervous System

4.2.1. Phylogeny of Cardiac Control

4.2.2. Methods for Investigating Cardiac Neuroanatomy

4.2.3. Extrinsic Cardiac Innervation

4.2.4. Intracardiac Nervous System

5. Cardiac Stroke Volume and Its Control

6. Coronary Blood Flow and Its Control

7. Summary

References

Chapter 5: Hormonal and Autacoid Control of Cardiac Function

1. Introduction

2. Catecholamines: Basal Control, Stress, and Cardiotoxicity

3. Angiotensin II

3.1. Short-Term Modulation

3.2. Long-Term Readjustments

4. Natriurectic peptides: Interface Between Myocardial Performance and Ion/FluidBalance

4.1. Structural Traits and Evolutionary Hints of the NP/NPR System

4.2. Fish Cardiac NP/NPR System

4.3. Osmoregulatory vs Cardioprotective Functions

5. Chromogranin A-Derived Peptides as Cardiac Stabilizers

5.1. Vasostatins and Catestatin Cardiac Influences

6. Gasotransmitters as Cardiac Modulators

6.1. Nitric Oxide as an Autocrine/Paracrine/Endocrine Mediator and CardioprotectiveFactor

6.1.1. Teleost NOS/NO System

6.1.1.1. Autocrine and Paracrine NO

6.1.1.2. Nitrite as a Bioactive NO Source and Endocrine Mediator

6.1.1.3. NO as a Cardioprotective Factor

6.2. Carbon Monoxide

6.3. Hydrogen Sulfide

7. Integrated Cardiac Humoral Signaling: The "Knot" of the NOS–NO System

8. Conclusions

References

Chapter 6: Cardiac Energy Metabolism

1. Introduction

2. Cardiac Energy State and Fundamentals of Cellular Energy Metabolism

3. Coupling Between Cellular Production and Consumption of ATP

4. Energy Demands of Cardiac Performance and Homeostasis

4.1. Myosin ATPase

4.2. Cellular Ion Regulation

4.2.1. Na+/K+-ATPase

4.2.2. Na+/Ca2+-Exchanger

4.2.3. Ca2+-ATPases

4.3. Basal Energy Requirements and Myocardial O2 Consumption

4.4. Myocardial O2 Consumption and Power Output Under Working Conditions

4.5. Protein Synthesis

5. Energy Substrates and Systems Used to Regenerate ATP

5.1. Substrate Selectivity

5.2. Biochemical Assays as Indicators of Cardiac Energy Metabolism

6. Hypoxia

7. Cold Temperature

7.1. Impacts of Cold Temperature on Cardiac Energy Metabolism

7.2. Impacts of Cold Temperature Acclimation on Cardiac Energy Metabolism

8. Body Size and Sex Differences in Cardiac Energy Metabolism

9. Remaining Questions, Challenges, and Future Directions

References

Chapter 7: Form, Function and Control of the Vasculature

1. Introduction

2. Gross Anatomy of the Vascular System

3. The Arterial Vasculature

3.1. Arterial Flow and Pressure

3.1.1. Pressure, Flow, and Resistance Relationships

3.1.2. Determinants of Vascular Resistance

3.1.3. Blood Viscosity

3.2. Control of Systemic Arterial Resistance and Blood Flow

3.2.1. Local Regulation of Arterial Resistance

3.2.1.1. Active hyperemia

3.2.1.2. Local Paracrine Signaling Molecules

3.2.1.3. Gasotransmitters

3.2.2. Neural Control of Arterial Resistance

3.2.2.1. The Autonomic Nervous System

3.2.2.2. Serotonin

3.2.2.3. Neuropeptides

3.2.3. Hormonal Control of Arterial Resistance

3.2.3.1. Circulating Catecholamines

3.2.3.2. Renin–Angiotensin System

3.2.3.3. Arginine Vasotocin

3.2.3.4. Bradykinins

3.2.3.5. Urotensins

3.2.3.6. Cholecystokinin

3.2.3.7. Adrenomedullins

3.2.3.8. Natriuretic Peptides

4. The Branchial Vasculature

4.1. Arrangement of the Gill Microvasculature

4.2. Control of Gill Blood Flow

4.2.1. Neural Control and Circulating Catecholamines

4.2.2. Other Hormones and Local Factors

5. The Venous Vasculature

5.1. Functional Characteristics and Gravity Effects

5.2. Venous Hemodynamic Principles

5.2.1. Central Venous Blood Pressure and Importance for Cardiac Performance

5.2.2. Venous Capacitance, Mean Circulatory Filling Pressure, and Venous Resistance

5.2.3. Passive Venous Changes Affecting Tissue Blood Volume

5.3. Neuroendocrine Control of Venous Capacitance

5.3.1. Neural Control Systems and Circulating Catecholamines

5.3.2. Other Vasoactive Hormones

5.3.2.1. Renin–Angiotensin System

5.3.2.2. Arginine Vasotocin

5.3.2.3. Natriuretic Peptides

5.3.3. Gasotransmitters and Locally Released Vasoactive Agents

5.4. Venous Function in Integrated Cardiovascular Responses

5.4.1. Elevated Metabolic Demand (Exercise and Elevated Temperature)

5.4.2. Barostatic Reflexes

5.4.3. Reflex Responses to Aquatic Hypoxia and Air Breathing

5.4.4. Changes in Water Salinity

Acknowledgments

References

Index

Other volumes in the fish physiology series

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