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99CARDIOVASCULAR SYSTEMHeart chambers1.right atrium: collecting chamber for incoming systemic venous system (deoxygenated blood)SA (sinoatrial) node - referred to as the pacemaker of the heart; located in the rightatrium (intrinsic rate of 100 impulses per minute)2.right ventricle: propels blood into pulmonary system3.left atrium: collects blood from pulmonary venous system (oxygenated blood)4.left ventricle: largest thick-walled muscle that acts as a high-pressure pump which propels bloodinto the systemic circulation responsible for cardiac outputHeart valves:membranous openings that allow one way blood flowatrioventricular valves: prevent backflow from ventricles to atria during systoleotricuspid - valve between right atrium and right ventricleomitral bicuspid - valve between left atrium and left ventriclesemilunar valves prevent backflow from aorta and pulmonary arteries into ventricles duringdiastoleopulmonic - valve between the right ventricle and pulmonary arteryoaortic - valve between left ventricle and aorta which leads to central circulationsystole - the phase of contraction during which the ventricles eject bloodventricle pushing blood through pulmonic valve ( is open)BP is higher during systolediastole - the phase of relaxation during which the ventricles fill with blood; when the heartpumps, myocardial layer contracts and relaxesMitral valve open to allow blood flow from Atria to VentricleBlood supply to heartThe heart itself is supplied with blood by the left andright coronary arteries, which are found atthebase of the aorta above the aortic valveoxygen, carbon dioxide, nutrients, and metabolic wastes are exchanged at the capillary level
the venous system, veins and venules, return the blood to the heartarteries – coronaryarteries that lead away from heartThe arteries contain a fibrous outer layer (tunica adventitia) that is stiff enough to holdthem open when cut. The veins collapse when cutThe aorta is the largest artery of the bodyoright supplies right ventricle and the back part of the left ventricleoleft supplies mostly left ventricle and septumveinsrely on valves to keep blood flowing in a single direction, back to the heart.All veins lead to the heart; it is arteries that lead away from itocoronary sinus - wide venous channel that drains five coronary veins into the rightatriumothebesian - the smallest coronary veins drain some venous blood directly into the rightatrium and ventricle and the left ventricleBlood flowdeoxygenated blood enters the right atrium through the superior and inferior vena cavathis blood enters the right ventricle through the tricuspid valvethe blood travels through the pulmonic valve to the pulmonary arteries and into the lungs whereexchange of oxygen and carbon dioxide gases occurs.