Cardiac Anatomy PDF

Cardiac Anatomy PARA 1002 1 Characteristics of the Heart Four chambered, muscular organ about the size of a clenched fist Average mass of adult heart: – Male: 310 g – Female: 225 g Myogenic - heartbeat originates within the heart Autorhy...

Cardiac Anatomy PARA 1002 1 Characteristics of the Heart Four chambered, muscular organ about the size of a clenched fist Average mass of adult heart: – Male: 310 g – Female: 225 g Myogenic - heartbeat originates within the heart Autorhythmic - depolarize spontaneously, regularly PARA 1002 2 1  Pericardium “Sac” that encloses the heart (3 layers) Fibrous pericardium – strong, dense connective tissue Serous pericardium (parietal, visceral) – one layer is continuous with the other “folding over” on itself forming pericardial cavity Visceral layer also considered outer layer of heart wall (epicardium) PARA 1002 3 Heart Wall Epicardium (visceral layer of serous pericardium) – contains surface fat Myocardium – layer of cardiac muscle bundles Endocardium – endothelium and connective tissue layer lining the heart chambers PARA 1002 4 2  Anterior View of the heart Pulmonary Aorta Pulmonary veins (right) trunk and pulmonary SVC arteries LA A=atrium RA V=ventricle LV RV IVC Apex of Heart PARA 1002 5 Posterior View of the Heart Pulmonary veins (right) RA LA IVC LV RV Apex of Heart Base of the heart is mostly the L. atrium PARA 1002 6 3  Right Atrium SVC Fossa ovalis Blood received from: superior vena cava, inferior vena cava, coronary sinus, anterior cardiac veins Right atrioventricular valve (tricuspid valve) >> to right ventricle IVC PARA 1002 7 Left Atrium Pulmonary Pulmonary veins (right) veins (left) Blood received from: lungs via pulmonary veins Left atrioventricular valve (bicuspid valve, mitral valve) >> to left ventricle PARA 1002 8 4  Ventricles Receive blood from the atria Considered the primary pumping chambers Pump blood out of the heart and into the major arteries (Aorta and Pulmonary Trunk) More muscular than atria (Why?) Left myocardium is thicker than the right (Why?) PARA 1002 9 Note the thickness of the ventricular wall. PARA 1002 10 5  Features of Ventricles (internal) Aorta AV valves: R- tricusp L- bicusp 1. Chordae tendineae AV 2. Papillary muscles AV 1 3. Trabeculae carneae 2 3 PARA 1002 11 Heart Valves Atrioventricular valves (AV valves) Connect respective atria and ventricles Right AV valve (tricuspid); Left AV valve (bicuspid, mitral) Semilunar valves (three cusps each) Connect ventricles with the “great arteries” Aortic (Aorta) and Pulmonary (Pulmonary Trunk) PARA 1002 12 6  Heart Valves Both types of valves prevent “backflow” of blood AV valves are associated with “muscle anchors” PARA 1002 13 AV Valve Function Papillary muscles and chordae tendinae prevent eversion of valves during atrial contraction PARA 1002 14 7  Semilunar Valve Function Closing of the semilunar valves is achieved as the cup- shaped cusps fill with blood following ventricular contraction PARA 1002 15 Blood Flow Right Atrium receives oxygen poor blood from systemic (body) and coronary (heart) circuits and the journey begins.. PARA 1002 16 8  Blood Flow R. atrium receives blood from SVC, IVC and coronary sinus Through tricuspid valve to right ventricle Through pulmonary semilunar valve to pulmonary trunk (L and R pulmonary arteries) Oxygenation in the lungs L atrium receives blood (oxygenated) via pulmonary veins (4) Through bicuspid (mitral) valve to left ventricle Through aortic semilunar valve to aorta >>> BODY PARA 1002 17 Coronary Vessels Ant. Post. Right Coronary Artery Left Coronary Artery Circumflex Artery Marginal Artery Great Cardiac Coronary Sinus Vein Most of the coronary veins drain into the coronary sinus, which opens into the RA PARA 1002 18 9  Coronary Blood Flow Note: heart requires a blood supply like any other organ Left Coronary Artery Right Coronary Artery AIV artery – anterior walls of Marginal – inferior boarder both ventricles on left side PIV – most of right ventricle Circumflex – left atrium and posterior part of L ventricle PARA 1002 19 Coronary Blood Flow Branches of both R and L coronary arteries supply both ventricles Atria receive blood from a small branch of corresponding coronary artery Greatest blood supply is to the left ventricle (Why?) Significant anatomical features: Very few anastomoses exist between larger coronary vessels – blood is not easily “rerouted” in the event of a blockage Such blockage (clots, occlusions) deprive cardiac muscle of oxygen (ischemia) resulting in myocardial infarction Numerous anastomoses exist between smaller vessels as well as the potential of formation of new ones… PARA 1002 20 10