Your Majestic Pump: The Human Heart APL3

Cardiovascular system Composed of: Composed of: –Heart –Blood vessels ( arteries, veins, capillaries) Vital for circulation: circulating oxygen to body and toxins (wastes) out Vital for circulation: circulating oxygen to body and toxins (wastes) out

Cardiac Output (Performance) Stroke volume: 80ml at rest Stroke volume: 80ml at rest Heart Rate: 70 bpm at rest; 180 during exercise Heart Rate: 70 bpm at rest; 180 during exercise Cardiac Output: SV * HR = 5600 ml/min Cardiac Output: SV * HR = 5600 ml/min Total blood volume is approx 5-6 liters. Your heart pumps almost entire volume of blood throughout body in 1 minute! Total blood volume is approx 5-6 liters. Your heart pumps almost entire volume of blood throughout body in 1 minute!

Your incredible engine! How much gas would the average car pump in its life? How much gas would the average car pump in its life? Blood pumped in 70 years: Blood pumped in 70 years: 206 million liters, or 50 million gallons 206 million liters, or 50 million gallons Most efficient engine ever made Most efficient engine ever made Typical hybrid car (60mpg) Typical hybrid car (60mpg) New cars (26.5 mpg) New cars (26.5 mpg)

Coverings of the Heart Double layered Pericardium Double layered Pericardium –Visceral: inner, delicate lining on surface of heart –Parietal: outer, tough sac fitting loosely around heart Pericardial cavity: space between 2 layers. Pericardial cavity: space between 2 layers. Filled with fluid to friction Filled with fluid to friction

Wall of heart: 3 Layers Epicardium: protective outer membrane Epicardium: protective outer membrane Myocardium: middle, heart wall, rich in blood Myocardium: middle, heart wall, rich in blood –Cardiac muscle Endocardium: inner lining of heart wall Endocardium: inner lining of heart wall –Purkinje fibers, collagen, elastin, BV’s

Heart chambers: Four 2 Atria: Thin walled upper chambers 2 Atria: Thin walled upper chambers –Receive blood 2 ventricles: Thick walled lower chambers 2 ventricles: Thick walled lower chambers –Pump blood out R. & L. sides separated by septum R. & L. sides separated by septum

One way blood flow: Valves One set separates the atria & ventricles One set separates the atria & ventricles Tricuspid: (3 cusps) Tricuspid: (3 cusps) Separates Right atria and R. ventricle Separates Right atria and R. ventricle Bicuspid: (2 cusps) Bicuspid: (2 cusps) Left atria & L. ventricle Left atria & L. ventricle

Valves cont’ Semilunar valves: separate the ventricles from the exits of the heart Semilunar valves: separate the ventricles from the exits of the heart Pulmonary SL valve separates R ventricle from the pulmonary artery Pulmonary SL valve separates R ventricle from the pulmonary artery Aortic SL valve separates L. ventricle from the aorta Aortic SL valve separates L. ventricle from the aorta

Arteries carry blood AWAY from the heart. Usually carry oxygenated blood. EXCEPT the pulmonary artery. Veins carry blood TOWARDS the heart. They usually carry deoxygenated blood. The exceptions are the pulmonary veins. “Arteries are better felt than seen and veins are better seen than felt.”