HEART BSMED 2-1 Introduction Cardiovascular system - heart, blood and blood vessels Cardiac muscle makes up bulk of heart provides force to pump blood Function - transports blood Generates BP Routing blood (pulmonary and systemic) Ensures one-way blood flow (valves) Regulates blood supply (rest, exercise) The Anatomy of the Heart Located in the mediastinum Surrounded by pericardial sac Cardiac Tamponade-fluid or blood due to trauma, MI, blood vessel rupture, die quickly fibrous pericardium - outer layer serous pericardium - inner layer Pericarditis – very painful; like heart attack The Layers of the Heart Wall Epicardium - outermost layer Pericardial cavity - separates epicardium and serous pericardium Myocardium - middle muscular layer Endocardium - lines the heart The Chambers of the Heart Upper chambers - right and left atria Lower chambers - right and left ventricles Chambers separated internally by septum External separations coronary sulcus - separates atria and ventricles interventricular sulci - separate ventricles The Great Vessels of the Heart Superior vena cava receives blood from upper body Inferior vena cava receives blood from lower body Coronary sinus - drains blood from heart The Great Vessels of the Heart Pulmonary trunk - right and left artery carries deoxygenated blood to lungs Pulmonary veins (four) - return oxygenated blood to heart Ascending Aorta - oxygenated blood out to body aortic arch, descending thoracic, abdominal The Valves of the Heart (Preventing Backflow) Atrioventricular Valves Tricuspid (three cusps) between right atrium and right ventricle Bicuspid (two cusps) between left atrium and left ventricle Cusps attach to ventricles by chordae tendineae Semilunar Valves Pulmonary right ventricle pulmonary trunk exits the heart Aortic left ventricle ascending aorta leaves the heart Some Major Blood Circulatory Routes Two Pumps Pulmonary Circulation Systemic Circulation Systemic Circulation All blood leaving left ventricle (oxygenated) All blood returning to right atrium (deoxygenated) Subdivisions coronary circulation hepatic portal circulation Other Circulatory Routes Pulmonary - blood flow to lungs for gas exchange Cerebral - route to the brain Fetal - between developing fetus and mother Blood Flow Through the Heart The Conduction System of the Heart Distribution of Electrical Impulses Through the Heart Sinoatrial (SA) node - pacemaker, initiates impulse Atrioventricular (AV) node - sends impulse to AV bundle Bundle of His - sends impulses to both sides of system Purkinje’s fibers - send impulse to myocardial cells A Cardiac Cycle One cycle atria contract / ventricles relax ventricles contract / atria relax Systole - contraction phase Diastole - relaxation phase
Posted on: Tue, 30 Jul 2013 10:26:19 +0000
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