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CARDIOVASCULAR SYSTEM. THE HEART Chapter 18. Physical Characteristics. Located in the mediastinum between the lungs and behind the sternum About the size of a clenched fist Shaped like an inverted cone Apex vs. Base. Coverings and Layers. Covering Around the Heart Pericardium
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CARDIOVASCULAR SYSTEM THE HEART Chapter 18
Physical Characteristics • Located in the mediastinum between the lungs and behind the sternum • About the size of a clenched fist • Shaped like an inverted cone • Apex vs. Base
Coverings and Layers • Covering Around the Heart • Pericardium • Fibrous pericardium • Serous pericardium • Parietal layer • Visceral layer (epicardium) • Serous fluid • Walls of the Heart • Epicardium • Myocardium • Endocardium
Chambers • Atria • Right atrium • Left atrium • Interatrial septum • Fossa ovalis • Ventricles • Right ventricle • Left ventricle • Interventricular septum
Valves • Atrioventricular valves • Tricuspid • Bicuspid (mitral) • Semilunar valves • Pulmonary semilunar • Aortic semilunar • Associated Structures • Chordae tendineae • Papillary muscles
Blood Flow Pulmonary Circuit Systemic Circuit Coronary Circuit Venous Drainage Blood Flow Animation
Pulmonary Circulation • Superior and inferior vena cava and coronary sinus • Right atrium • Tricuspid • Right Ventricle • Pulmonary semilunar • Pulmonary arteries • Lungs
Systemic Circulation • Pulmonary veins • Left atrium • Bicuspid valve • Left ventricle • Aortic semilunar • Systemic aorta • Coronary artery
Coronary Circulation • Left coronary artery • Anterior interventricular artery • Circumflex artery • Right coronary artery • Posterior interventricular artery • Marginal artery • Arterial anatomoses
Venous Drainage • Superior vena cava • Inferior vena cava • Great cardiac vein • Small cardiac vein • Middle cardiac vein • Coronary sinus
Extrinsic Cardiac Conduction System • Autonomic Innervation • Sympathetic nervous system • Parasympathetic nervous system
Cardiac Physiology EKG Heart Sounds Cardiac Cycle
Heart Sounds • Auscultate • Stethoscope • Lub-dup, pause, lub-dup, pause, etc • Lub= AV valves closing • Dup=Semilunar valves closing
Cardiac Output • Cardiac output (CO) = the amount of blood pumped by each ventricle per minute • CO = SV X HR • SV=“stroke volume” or the amount of blood pumped by a ventricle in a single beat • HR=“heart rate” or number of beats per minute
Contractility Positive Inotropic Agents - Sympathetic NS - Digitalis - Glucagon (pancreas) - Epinephrine - Hypercalcemia Negative Inotropic Agents - Hyperkalemia - Hypocalcemia - Cardiac hypoxia - Cardiac hypercapnia
Factors Affecting HR • Autonomic nervous system • Hormones: epinephrine and thyroxine • Age, gender, fitness, emotional state • Body temperature • Ion concentrations in body fluids • Blood pressure
Cardiac Disorders • Valve disorders • Heart murmur • Stenosis • Incompetent valve • Mitral valve prolapse • Rheumatic fever or Streptococcus infection • Sclerosis and thickening of valve flaps • Arrhythmias • Tachycardia • Bradycardia • Fibrillation • Heart block
Cardiac Disorders • Other related heart problems • Ischemia and hypoxia • Angina pectoralis • Myocardial infarction • Heart palpitation • Asystole • Myocarditis • Endocarditis • Cardiac tamponade • Pericarditis • Congenital defects • Congestive heart failure