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 con’t –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: [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.