Cardiac Muscle

A. General Introduction.- B. Morphology of Cardiac Muscle.- I. Light Microscopy of Cardiac Muscle.- II. Ultrastructure of Cardiac Muscle.- 1. Sarcolemma.- 2. Caveolae.- 3. T System.- 4. Intercellular Junctions.- a) Nexus.- b) Desmosome.- c) Fascia Adherens.- 5. Sarcoplasmic Reticulum.- a) Junctional SR.- b) Network (Free) SR.- ?) Central Region of Sarcomere.- ?) Z Disc Region.- ?) Mitochondrial Network SR.- c) Function of SR.- 6. Myofibrillar System.- a) Contractile Elements.- b) Sarcomeric Arrangement of Myofilaments.- c) Myosin ATPase Activity.- d) Myosin Subunits.- e) Z Disc (Band).- 7. Cytoskeleton.- a) Intermediate Filaments.- b) Microtubules.- c) Leptofibrils.- 8. Mitochondria.- 9. Lysosomes.- 10. Atrial Specific Granules.- 11. Other Cell Organelles and Inclusions.- III. Histochemistry.- IV. Extracellular Matrix.- V. Venous Cardiac Muscle.- C. Morphometry of Cardiac Muscle.- I. Methodology.- II. Factors Influencing Morphometric Parameters.- III. Morphometric Parameters in Adult Myocardium.- 1. Myocyte Density and Ratio of Myocytes and Capillaries.- 2. Dimensions of Myocytes.- 3. Composition of the Myocardium.- 4. Composition of Myocytes.- a) Myofibrils.- b) Mitochondria.- c) Nucleus and Matrix.- d) Sarcoplasmic Reticulum and T System.- D. The Conduction System.- I. The Sinoatrial Node.- 1. Location.- 2. Histology.- 3. Ultrastructure of SA Nodal Cells.- a) SA Nodal Cell Size.- b) Myofibrillar System.- c) T System and Sarcoplasmic Reticulum.- d) Mitochondria, Other Organelles and Glycogen.- e) Caveolae.- f) Intercellular Junctions and Basal Lamina.- 4. Transitional Cells.- 5. Intercalated Clear Cells.- 6. Correlation Between Electrophysiological Pacemakers and the Morphological SA Node.- 7. Shifting Locations of the Leading Pacemaker.- 8. Internodal Myocardium.- 9. The Nodal Artery.- II. The Atrioventricular Junctional Tissues.- 1. Location.- 2. Definition of the AV Nodal-Bundle Junction.- 3. Non-Junctional Atrial Myocardium Near the AV Junction.- 4. Converging Preferential Pathways.- 5. Transitional Cell Zone.- 6. The Compact Node.- 7. Individual Variation.- 8. Species Differences.- a) Topography.- b) Connective Tissue.- c) Subdivisions of the AV Junction.- 9. Ultrastructure of the AV Nodal Tissues.- a) Transitional Cells.- b) AV Nodal Cells.- 10. Correlations Between Ultrastructurally- and Electrophysiologically-defined Zones.- 11. Anomalous AV Conduction Pathways.- III. The Ventricular Purkinje System.- 1. Introduction.- a) Distribution.- b) Conduction Velocity.- c) Purkinje Network.- 2. Species Differences.- 3. Ultrastructure of Purkinje Fibres.- a) Purkinje Type I, II and III.- b) T System.- c) Purkinje Myofibrillar Arrangement.- d) Alterations of the Myofibrillar System.- e) Myosin Subunit Composition.- f) Myosin ATPase Activity.- g) Intermediate Filaments.- h) Leptofibrils.- i) Intercellular Junctions.- IV. Histochemistry of Mammalian Conduction Systems.- a) Glycogen.- b) Lipids.- c) Metabolic Enzymes.- V. Non-Mammalian Conduction Systems.- 1. Anatomy of the Non-Mammalian Vertebrate Heart.- 2. Lower Vertebrates.- a) Physiology.- b) Histology.- c) Ultrastructure.- 3. Birds.- a) Sinoatrial Node.- b) Atrioventricular Node.- c) Ventricular Purkinje System.- 4. Phylogenetic Correlations.- E. Innervation of the Heart.- I. Major Nerves Supplying the Heart.- II. Sensory End Formations.- 1. Myelinated Fibres.- 2. Morphological Types of Sensory End Formations.- a) End-Nets.- b) Unencapsulated Endings.- c) Encapsulated Endings.- 3. Ultrastructure of Sensory End Formations.- a) Afferent and Efferent Fibres Supplying End Formations.- b) Cells and Nerve Endings Within the End Formation.- c) Chemoreceptors.- III. Histochemical and Chemical Studies of Efferent Fibres.- 1. Distribution of Parasympathetic Nerves.- a) Comparison of the Four Chambers.- b) Densely-Innervated Atrial Muscle Bundles.- c) Functional Implications of Densely-Innervated Atrial Muscle Bundles.- 2. Distribution of Sympathetic Nerves.- a) Catecholamine Fluorescence Studies.- b) Comparisons with Chemical Studies.- c) Evidence for Different Types of Sympathetic Nerves in the Heart.- 3. Species Differences and Regional Variation of AV Nodal Innervation.- IV. Ultrastructure of Neuromuscular Relationships in the Heart.- 1. Terminology.- a) En Passant.- b) Close Associations.- c) Intimate Contacts.- d) Direct and Diffuse Innervation.- e) Cholinergie and Adrenergic Varicosities.- 2. Innervation of Working Myocardium.- 3. Innervation of the SA Node.- 4. Innervation of the AV Junctional Tissues.- a) Efferent Fibres.- b) Sensory Endings.- c) Species Differences and Regional Variation.- 5. Innervation of the AV Bundle and Purkinje Fibres.- a) Nerve Fibre Density.- b) Efferent Fibres.- c) Sensory Endings.- d) Species Differences and Regional Variation.- 6. An Alternative Concept for the Role of the Intrinsic Innervation of the Heart.- V. Innervation of Non-Mammalian Cardiac Muscle.- 1. Fishes.- a) Parasympathetic Innervation.- b) Sympathetic Innervation and Circulating Catecholamines.- c) Chromaffin Tissue.- d) Morphology of Innervation.- 2. Amphibians and Reptiles.- a) Functional Anatomy.- b) Ultrastructure.- F. Development of Cardiac Muscle.- I. Developmental Stages.- II. Embryonic Heart Formation.- 1. Cardiogenic Crescent.- 2. Development of the Epicardium.- 3. Development of the Endocardium.- III. Formation of the Four-Chambered Heart.- 1. Looping.- 2. Septation.- IV. Development of the Coronary Circulation.- V. Ultrastructure of Developing Cardiac Muscle.- 1. Cytodifferentiation.- 2. Ventricular Myocardium.- a) Myofibrils.- b) Mitochondria.- c) Glycogen.- d) Nucleus and Perinuclear Region.- e) T System.- f) Sarcoplasmic Reticulum.- g) Intercalated Disc.- h) Other Cytoplasmic Constituents.- 3. Mitosis.- 4. Cell Death.- 5. Atrial Myocardium.- VI. Morphometric Changes During the Growth of Myocytes.- 1. General Features.- 2. Dimensions.- 3. Volume Composition of the Myocardium.- 4. Volume Composition of Myocytes.- a) Myofibrils.- b) Mitochondria.- c) Mitochondrial/Myofibrillar Ratio.- d) Matrix.- e) Nucleus.- f) Sarcoplasmic Reticulum.- g) T System.- 5. Correlation of Structure and Function in Developing Myocytes.- G. Development of the Conduction System.- I. Conduction in Embryonic Heart.- 1. ECG of Embryonic Heart.- 2. Preferential Conduction in the AV Canal.- 3. Preferential Conduction in the Ventricular Trabeculae.- II. Development of the Sinoatrial Node.- 1. Development of the Pacemaker.- 2. Cell Coupling in the Absence of Gap Junctions.- 3 Timing of First Appearance and Position of the SA Node.- 4. Cytological Differentiation.- 5. Innervation.- 6. Bilateral Nodal Primordia.- III. Development of the AV Node.- 1. Formation of the AV Node.- 2. Evidence for Species Differences.- 3. The Specialized Ring Tissue Theory.- 4. Innervation.- IV. The Development of the Ventricular Purkinje System.- 1. Differentiation.- 2. Formation of the Purkinje Network.- 3. Theories of Purkinje Fibre Development.- a) Ventriculomyocardium Theory.- b) Specialized Precursor Tissue Theory.- c) The Specialized Ring Tissue Theory.- H. Cardiac Hypertrophy.- I. General Features.- II. Morphological Changes.- III. Morphometric Changes.- IV. Regional Patterns.- I. Regeneration.- J. Cardiac Muscle Cells in Culture.- I. Introduction.- II. Methods of Culture.- 1. Methodology.- a) Monolayer.- b) Synthetic Strand.- c) Cluster.- d) Polystrand.- 2. Culture Medium.- III. Working Myocardium in Culture.- 1. Morphology.- 2. Intercellular Junctions.- 3. Mitosis.- 4. Metabolism.- a) ATP as an Energy Source.- b) Lipid Metabolism.- c) Carbohydrate Metabolism.- d) Amino-Acid Metabolism.- 5. Synthesis of Prostaglandins.- 6. Contractility.- a) Use of Automatic Monitors.- b) Effect of Anaesthetics.- c) Effect of Autonomic Agonists and Antagonists.- d) Effect of Colchicine.- e) Effect of Dibutyryl Cyclic AMP.- 7. Hypoxia.- 8. Electrical Properties.- a) Monolayers and Reaggregates.- b) Changes in Membrane Composition.- 9. Transmembrane Ion Fluxes.- a) Calcium Homeostasis.- b) Calcium Regulation of Cyclic AMP and Beating.- c) Calcium in Myocardial Cell Injury.- d) Other Ion Fluxes.- 10. Effect of Hormones and Drugs.- a) Parathyroid Hormone.- b) Diazepam.- 11. Receptor Modulation.- a) Adrenergic.- b) Cholinergie.- IV. Cellular Interactions.- 1. Nerve - Muscle.- a) Tropic Interactions.- b) Functional Junctions.- 2. Muscle - Non Muscle.- V. Other Cardiac Muscle.- 1. Cardiac Muscle from Blood Vessels.- 2. Conducting System.- References.- Author Index.