Cardiac muscle The major types of cardiac muscle Atrial muscle Contractile cells (收缩细胞) Ventricular muscle Specialized excitatory and conductive Autorhythmic cells muscle (自律细胞)
• The major types of cardiac muscle: – Atrial muscle – Ventricular muscle – Specialized excitatory and conductive muscle Contractile cells （收缩细胞） Autorhythmic cells （自律细胞） Cardiac muscle 6
Cardiac muscle metabolism At rest, cardiac muscle consumes fatty acids to supply most of its energy (70% fatty acids vs. 30% carbohydrates Under fasting state, almost all of the energy comes from fatty acid oxidation Under anaerobicor ischemic conditions, glycolysis is required which consumes tremendous amounts of blood glucose and forms large amount of lactic acids
Cardiac muscle metabolism • At rest, cardiac muscle consumes fatty acids to supply most of its energy (70% fatty acids vs. 30% carbohydrates). • Under fasting state, almost all of the energy comes from fatty acid oxidation. • Under anaerobic or ischemic conditions, glycolysis is required, which consumes tremendous amounts of blood glucose and forms large amount of lactic acids. 7
Conducting system of the heart Copyright e The McGraw-Hill Companies, Inc. Permission required for reproduction or display perior Atrioventricular node vena cava Bundle of His Sinoatrial node Left atrium Right atrium Right bundle branch ventricle Right ventricle fibers Inferior vena cava Interventricular Left bundle branch 8
Conducting system of the heart 8
Innervation Parasympathetic Innervation Sympathetic Innervation (cholinergic: Vagus nerves) (adrenergic) Acetylcholine Norepinephrine B1 adrenergic receptor M acetylcholine receptor Epinephrine Adrenal gland Kidney
Innervation Norepinephrine β1 adrenergic receptor M acetylcholine receptor Acetylcholine Kidney Adrenal gland Epinephrine 9
Cardiac cells gap junction Cardiac cells are electrically coupled through gap junctions. Is an electrical synapse that permits electrical current to flow between neighboring cells Gap junctions Myocatdial cells
Cardiac cells’ gap junction • Cardiac cells are electrically coupled through gap junctions. • Is an electrical synapse that permits electrical current to flow between neighboring cells. . 10