Cardiovascular System

Role of Cardiovascular System Transport O2 and nutrients to tissues Remove CO2 and waste products from tissues Maintenance of constant body temperature Prevention of infection

Anatomy of the Heart Cardiac muscle About size of fist Located in thoracic cavity between lungs directly behind sternum Titled  Apex (pointed end) is oriented to left

Walls of heart: Pericardium – protective sac (reduces friction) Epicardium – outer layer Myocardium – layer made of cardiac muscle Endocardium – innermost layer

Separated by interventricular septum Right heart = right pump The “Double Pump” Right and left heart Separated by interventricular septum Right heart = right pump Pump deoxygenated blood (just returned from body) to the lungs Pulmonary circulation Left heart = left pump Pump oxygenated blood (just returned from lungs) to the rest of the body Systemic circulation

4 chambers Upper chambers = Atria (right & left) Lower chambers = Ventricles (right & left) Left ventricle (thickest) – pump blood through entire body Right ventricle – pump blood short distance to lungs

Heart Valves Valves where blood leaves ventricles Atria & ventricles separated by valve = Atrioventricular (AV) valves Allows only one flow of blood (atria  ventricles) Right side of heart  tricuspid valve Prevent backflow from right ventricle to right atrium Left side of heart  bicuspid (or mitral) valve Prevent backflow from left ventricle to left atrium Valves where blood leaves ventricles Right side of heart  Pulmonary semilunar valve Prevent backflow from pulmonary arteries to right ventricle Left side of heart  Aortic semilunar valve Separates aorta from left ventricle

Pathway of Blood Flow Right atrium receives deoxygenated blood from superior & inferior vena cava Superior vena cava = returns blood from upper body Inferior vena cava = returns blood from lower body Blood moves from right atrium (through tricuspid vavle) to the right ventricle (passes tricuspid valve) Pumped out of pulmonary arteries (through pulmonary semilunar valve) to lungs pumps it to the lungs This is known as PULMONARY CIRCULATION

Oxygenated blood returns from lungs  now O2-rich Through pulmonary veins into left atrium Blood travels from left atrium (through bicuspid valve) to left ventricle Blood enters aorta (through aortic semilunar valve) & pumps to the whole body This is known as SYSTEMIC CIRCULATION

Arteries & Veins Arteries = vessels that carry blood away from heart Veins = vessels that carry blood toward heart

In systemic circulation, arteries carry oxygenated blood from heard to body tissues, while veins carry deoxygenated blood back to heart In pulmonary circulation, pulmonary arteries carry deoxygenated blood from heart to lungs, while pulmonary veins carry oxygenated blood from lungs back to heart