Contribute little to propulsion of blood Three veins empty into right atrium

Contribute little to propulsion of blood three veins

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Contribute little to propulsion of blood Three veins empty into right atrium: Superior vena cava, inferior vena cava, coronary sinus Four pulmonary veins empty into left atrium Ventricles: The Discharging Chambers Most of the volume of heart Right ventricle - most of anterior surface Left ventricle – posteroinferior surface Trabeculae carneae – irregular ridges of muscle on walls Papillary muscles – anchor chordae tendineae Ventricles: The Discharging Chambers Thicker walls than atria Actual pumps of heart Right ventricle Pumps blood into pulmonary trunk Left ventricle Pumps blood into aorta (largest artery in body) Heart Valves Ensure unidirectional blood flow through heart Open and close in response to pressure changes Two atrioventricular (AV) valves Prevent backflow into atria when ventricles contract Tricuspid valve (right AV valve) Mitral valve (left AV valve, bicuspid valve) Chordae tendineae anchor cusps to papillary muscles Hold valve flaps in closed position
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Heart Valves Two semilunar (SL) valves Prevent backflow into ventricles when ventricles relax Open and close in response to pressure changes Aortic semilunar valve Pulmonary semilunar valve Pathway of Blood Through the Heart Pulmonary circuit Right atrium tricuspid valve right ventricle Right ventricle pulmonary semilunar valve pulmonary trunk pulmonary arteries lungs Lungs pulmonary veins left atrium Pathway of Blood Through the Heart Systemic circuit Left atrium mitral valve left ventricle Left ventricle aortic semilunar valve aorta Aorta systemic circulation Pathway of Blood Through the Heart Equal volumes of blood pumped to pulmonary and systemic circuits Pulmonary circuit short, low-pressure circulation Systemic circuit long, high-friction circulation Anatomy of ventricles reflects differences Left ventricle walls 3X thicker than right Pumps with greater pressure Coronary Circulation: Arteries Arteries arise from base of aorta Left coronary artery branches anterior interventricular artery and circumflex artery Supplies interventricular septum, anterior ventricular walls, left atrium, and posterior wall of left ventricle
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Right coronary artery branches right marginal artery and posterior interventricular artery Supplies right atrium and most of right ventricle Coronary Circulation: Veins Cardiac veins collect blood from capillary beds Coronary sinus empties into right atrium; formed by merging cardiac veins Great cardiac vein of anterior interventricular sulcus Middle cardiac vein in posterior interventricular sulcus Small cardiac vein from inferior margin Homeostatic Imbalances Angina pectoris Thoracic pain caused by fleeting deficiency in blood delivery to myocardium Cells weakened Myocardial infarction (heart attack) Prolonged coronary blockage
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