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• HeartFour-chambered, hollow, muscular organ, not much bigger than a fistLies in the mediastinumLower border is called the apexHeart wall: three layers• Epicardium: serous membrane on the outside of the heart• Myocardium: constructed of cardiac muscle• Endocardium: lines the inner surface of the chambers of the heart• Heart chambersRight atrium—receives deoxygenated bloodLeft atrium—receives oxygenated bloodRight ventricle—pumps deoxygenated bloodLeft ventricle—pumps oxygenated blood• Heart valvesAtrioventricular valves• Tricuspid and bicuspid valvesSemilunar valves• Pulmonary and aortic semilunar valves• Electrical conduction systemAutomaticity• An inherent ability of the heart muscle tissue to contract in a rhythmic patternIrritability• The ability to respond to a stimulusImpulse pattern• Sinoatrial node to AV node to bundle of His to right and left bundle branches to Purkinje fibers• Cardiac cycleA complete heartbeat• Atria contract while ventricles relax• Ventricles contract while atria relaxSystole• Phase of contractionDiastole• Phase of relaxation• Period between contraction of the atria or ventricles during which the blood enters the relaxed chambers• Blood vesselsCapillaries• Tiny blood vessels joining arterioles and venulesArteries• Large vessels carrying blood away from the heartVeins• Vessels that convey blood from the capillaries to the heart• Coronary blood supplyRight and left coronary arteries
• Branch off of the aorta• Encircle the heart like a crown• Supply the myocardium with blood - the myocardium is the first tissue to be supplied with oxygenated blood with each heartbeatRight Coronary Artery (RCA) supplies oxygenated blood to:- right atrium - inferior wall left ventricle- right ventricle - posterior wall left ventricleLeft Anterior Descending Artery which supplies O2 blood to:- anterior wall of the left ventricleLeft Circumflex Artery which supplies O2 blood to:- left atrium- lateral left ventricleCoronary veins• Return the unoxygenated blood to the coronary sinus, then to the right atrium• Systemic circulationCirculates blood from the left ventricle to all parts of the body and back to the right atriumCarries oxygen and nutritive materials to all body tissues and removes products of metabolism• Pulmonary circulationCirculates blood from the right ventricle to the lungs and back to the left atrium of the heartCarries deoxygenated blood to the lungs to be reoxygenated and removes the metabolic waste product, carbon dioxideFluoroscopyAn action picture radiograph (x-ray), which allows observation of movement. It is used for pacemaker and intracardial catheter placementAngiogram (AngiocardiographyA radiopaque dye is injected into a vessel and its movement through the heart is recorded by a series of radiographic pictures taken in rapid succession. The pictures