The Cardiovascular System  A closed system of the heart and blood vessels The heart pumps blood Blood vessels allow blood to circulate to all parts of the body a.Pulmonary circuit—flow of blood through the lungs.  Pulmonary arteries—carry O 2 -poor blood from right ventricle to the lungs.  Pulmonary veins—carry O 2 -rich blood from lungs to the left atrium. b.Systemic circuit—flow of blood through the rest of the body.  Aorta—carries O 2 -rich blood to all body tissues.  Vena cava—returns O 2 -poor blood to the right atrium.  The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

The Heart: Size & Location  The heart is a hollow, cone-shaped, muscular pump  Nine (9) inches long x three (3) inches wide.  Located in the centre of Thorax between the lungs posteriorly by the backbone, and anteriorly by the sternum & resting upon the diaphragm.  Base--attached to several large blood vessels and lies beneath the second rib.  Pointed apex at the fifth intercostal space directed toward left

Location of Heart in thorax

The Heart: Associated Great Vessels  Aorta  Leaves left ventricle  Pulmonary arteries  Leave right ventricle  Vena cava  Enters right atrium  Pulmonary veins  Enter left atrium

Right Heart Chambers Right Heart Chambers Right Atrium –Receives O 2 -poor blood from body via Superior and Inferior vena cava Right Ventricle –Receives O 2 -poor blood from right atrium through tricuspid valve –Pumps blood to lungs via Pulmonary Semilunar Valve in pulmonary trunk Left Heart Chambers Left Atrium –Receives O 2 -rich blood from lungs via 4 Pulmonary Veins Left Ventricle (forms apex of heart) –Receives blood from Left Atrium via bicuspid valve (Mitral valve ) –Pumps blood into aorta via Aortic Semilunar Valve to body

Heart Chambers and Valves