The Heart Position Structure Function Electricity Pathology Diagnostic Tests Position of the Heart Located between the lungs in the thoracic cavity Centered in the chest Structure of the Heart The size of your heart is comparable to the size of your fist. Structure of the Heart The heart is enclosed in a protective membrane called the pericardium. The inner layer: visceral pericardium The outer layer: parietal pericardium Structure of the Heart The walls of the heart are mostly made up of myocardium (heart muscle) Consists of parietal pericardium, fatty tissue, coronary vessels, pericardial space, visceral pericardium, myocardium, and endocardium Turn to page 375 Structure of the Heart S EPTUM LeftRight Structure of the Heart 4 Chambers: The upper chambers: the right & left atrium The lower chambers: the right & left ventricle The atria are smaller, thinner than the muscular ventricles of the heart Myocardium in the left ventricle is thicker than the right ventricle moves blood to greater distances in the body Structure of the Heart 4 Valves 2 valves separating the atria and the ventricles Bicuspid (Mitral) valve on the left side Tricuspid valve on the right side Structure of the Heart 2 valves exiting the ventricles Aortic Semilunar valve exiting the right ventricle Pulmonary Semilunar valve exiting the left ventricle Structure of the Heart Bicuspid and Tricuspid valves Held in place by Chordae tendineae which helps prevent backflow Function of the Heart Consists of a double-pump Left side of the heart moves blood throughout the body and returns it to the right atrium (Systemic Circuit) Right side of the heart moves blood to the lungs and returns it to the left atrium (Pulmonary Circuit) Function of the Heart Blood Circulation Brings Oxygen and Nutrients to the body Removes Carbon Dioxide and wastes out of the body Electricity of the Heart Electrical signals (impulses) rhythmically keep the heart pumping Each complete heartbeat is considered a Cardiac Cycle Each cycle takes approximately 0.8 secs Electricity of the Heart Contractions of the heart Systole Relaxation of the heart Diastole Electricity of the Heart Impulses follow a continuous pattern Sinoatrial node (SA) node Atrioventricular (AV) node AV bundle or bundle of His Purkenje fibers Pathology of the Heart Cardiac disease can be... Structural Electrical Pathology of the Heart Terms of structural problems Angina pectoris Cardiac tamponadeCardiac tamponade Cardiomegaly Cardiomyopathy Congestive heart failure Coronary embolism Endocarditis Pathology of the Heart Terms of structural problems cont Incompetent valveIncompetent valve Mitral valve prolapse Myocardial infarction Pericarditis Pericardial effusion Rheumatic heart disease Stenosed valve Pathology of the Heart Terms for Electrical problems: Bradycardia Dysrhythmia Extrasystoles PACs & PVCs Fibrillation atrial & ventricular Sinus dysrhythmia Tachycardia Diagnostic Tests Angiography Cardiac catheterization Echocardiography Electrocardiography Holter monitoring Magnetic resonance imaging Stress test References Causey, L. (Designer). (2011). small_fist [Image], Retrieved January 28, 2012, from:http://www.aperfectworld.org/clipart/gestures/fist_small.png [Image of electricity]. Retrieved January 30, 2012, from:[Image of electrocardiogram]. January 30, 2012, from:[Image of heart in thoracic cavity]. Retrieved January 28, 2012, from:if [Image of one way valve]. Retrieved January 30, 2012, from:[Image of pericardium]. Retrieved on January , from:Louwinger, O. Whelan, G. & Taddei, M. (2007). The Human Body Book. New York, NY: Dorling Kindersley. Thibodeau, G. A. & Patton, K. T. (2010). The Human Body in Health & Disease (5 th ed.). St.Louis, MO: Mosby Elsevier.