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

Differences between the Ventricles

Valves Atrioventricular valves –Tricuspid –Bicuspid (mitral) Semilunar valves –Pulmonary semilunar –Aortic semilunar Associated Structures –Chordae tendineae –Papillary muscles

Valves

AV Valves

Semilunar Valves

Heart Valve Video Heart Valve Video

Microscopic Anatomy

Blood Flow Pulmonary Circuit Systemic Circuit Coronary Circuit Venous Drainage Blood Flow Animation

Pulmonary vs. Systemic

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

Posterior View

Venous Drainage Superior vena cava Inferior vena cava Great cardiac vein Small cardiac vein Middle cardiac vein Coronary sinus

Posterior View

Anastomoses of Coronary Circulation

Cardiac Conduction Systems

Intrinsic Cardiac Conduction System Animation Intrinsic Cardiac Conduction System Animation

Extrinsic Cardiac Conduction System Autonomic Innervation –Sympathetic nervous system –Parasympathetic nervous system

Cardiac Physiology EKG Heart Sounds Cardiac Cycle

Electrocardiograph

EKG and Conduction

EKG Animation EKG Animation

Abnormal ECG

Heart Sounds Auscultate Stethoscope Lub-dup, pause, lub-dup, pause, etc Lub= AV valves closing Dup=Semilunar valves closing

Cardiac Cycle Animation Cardiac Cycle Animation

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

Factors Affecting SV

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

Homeostasis

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