Heart Anatomy © Approximately the size of your fist © Wt. = 250-300 grams ® Location © In the mediastinum between the lungs ® Superior surface of diaphragm © %'s of it lies to the left of the midsternal line © Anterior to the vertebral column, posterior to the sternum aE —$<—$_—= Hea rt Anatomy ie ornal tnd Stermum Diaphragm, Point of ‘Superior ‘vena cava Lott ung Aorta Pariotat pleura (cut) Pulmonary ‘twunk Pariotat pericardium (cut) ‘Apex of heartCoverings of the Heart © Pericardium - a double-walled sac around the heart © Composed of: ® A superficial fibrous pericardium * A deep two-layer serous pericardium © The parietal layer lines the internal surface of the fibrous pericardium * The visceral layer or epicardium lines the surface of the heart © They are separated by the fluid-filled pericardial cavity called the pericardial cavity © Protects and anchors the heart © Prevents overfilling of the heart with blood ® Allows for the heart to work ina relatively friction-free environment Pericardial Layers of the Heart Layers of the Heart Wall © Epicardium - visceral pericardium a © Myocardium - cardiac muscle if i layer forming the bulk of the heart © Endocardium ~ endothelial layer of the inner myocardial surfaceHeart Anatomy © External markings ® Apex - pointed inferior region © Base - upper region ® Coronary sulcus © Indentation that separates atria from ventricles © Anterior and posterior interventricular sulcus © Separates right and left ventricles ® Internal divisions © Atria (superior) and ventricles (inferior) © Interventricular and interatrial septa Atria of the Heart ® Atria - receiving chambers of the heart © Receive venous blood returning to heart © Separated by an interatrial septum (wall) © Foramen ovale - opening in interatrial septum in fetus © Fossa ovalis - remnant of foramen ovale © Each atrium has a protruding auricle © Pectinate muscles mark atrial walls © Pump blood into ventricles © Blood enters right atria from superior and inferior venae cavae and coronary sinus © Blood enters left atria from pulmonary veinsPoss: Anatomy of Heart: Frontal Section ‘Aorta ‘Superior vena cave, —— Lott Right Si pulmonary artery Pulmonary trunk ~ ight atrium ‘ pulmonary veins ‘Mitral (bicuspid) vaive Aortic ‘semilunar valve Pulmor ‘semitunar vaive Triouspia Lott ventricle valve Right ventricle Chordae pericardium Ventricles of the Heart © Ventricles are the discharging chambers of the heart © Papillary muscles and trabeculae carneae muscles mark ventricular walls © Separated by an interventricular septum © Contains components of the conduction system © Right ventricle pumps blood into the pulmonary trunk © Left ventricle pumps blood into the aorta ® Thicker myocardium due to greater work load © Pulmonary circulation supplied by right ventricle is a much low pressure system requiring less energy output by ventricle © Systemic circulation supplied by left ventricle is a higher pressure system and thus requires more forceful contractionsal Heart: Anterior Vi Brnchiocephalic artery pulmonary artery Asconding aorta Pulmonary trunk Right pulmonary veins Right atrium Right coronary artery (in right atrioventricular groove) Anterior cardiac vain Right ventricle Marginal artery Small cardiac vein Inferior Left common carotid artory Left pulmonary artery Left pulmonary veins Left atrium ‘Autiole Cireumttox artery Left coronary artery (in left atrioventricular groove) Left ventricle Groat cardiac woin Anterior Interventrioular artory (in anterior Inerventricular sulcus) Apex Structure of Heart Wall © Left ventricle - three times thicker than right © Exerts more pumping force © Flattens right ventricle into a crescent shape Right Figure 18,7Fibrous Skeleton ® Surrounds all four valves © Composed of dense connective tissue © Functions ® Anchors valve cusps ® Prevents overdilation of valve openings © Main point of insertion for cardiac muscle © Blocks direct spread of electrical impulses Heart Valves 9s -remmnen Vi; ‘arte valve aN ‘Area of eutawoy (a titas vaive Senmajor Vessels of the Heart © Vessels returning blood to the heart include: % ; se © Open into the right atrium * Return deoxygenated blood from body cells © Coronary sinus © Opens into the right atrium * Returns deoxygenated blood from heart muscle (coronary veins) = : * Open into the left atrium * Return oxygenated blood from lungs major Vessels of the Heart ® Vessels conveying blood away from the heart include: © Pulmonary trunk © Carries deoxygenated blood from right ventricle to lungs ® Splits into right and left pulmonary arteries . a © Carries oxygenated blood away from left atrium to body « a * Three major branches | © Brachiocephalic * Left common carotid, * Left subclavian arteryCoronary Circulation © Coronary circulation © The functional blood supply to the heart muscle itself ® Rand L Coronary arteries are 1st branches off the ascending aorta ® Coronary sinus (vein) empties into R. atrium ® Collateral routes ensure blood delivery to heart even if major vessels are occluded Soronary Circulation - ® Supplies blood to © Right atrium and posterior surface of both ventricles © Branches into the © Marginal artery - extends across surface of R. ventricle * Found in posterior interventricular sulcus e © Supplies blood to © Left atrium and left ventricle © Branches into © Circumflex artery © Anterior interventricular artery * Found in anterior interventricular sulcus © Connected with posterior interventricular artery via arterial anastomosesCoronary Circulation: Arterial Supply Aorta Pulmonary trunk coronary artery Marginal artery (a) Fic 187% Coronary Circulation - Veins © Coronary sinus = © Vein that empties into right atrium © Receives deoxygenated blood from: © Great cardiac vein - on anterior surface * Posterior cardiac vein * Drains area served by circumflex * Middle cardiac vein © Drains area served by posterior interventricular artery © Small cardiac vein * Drains blood from posterior surfaces of right atrium and ventricle Middle cardiac vein