The Heart … and blood flow

Heart Facts Your heart is about the same size as your fist An average adult body contains about five quarts of blood (1.25 gallons) All the blood vessels in the body joined end to end would stretch 62,000 miles or two and a half times around the earth.

Heart Facts continued…. The heart circulates the body’s blood supply ~1000 times each day The heart pumps the equivalent of 1,250 to 1,500 gallons of blood each day The heart beats about 42,075,904 times per YEAR – imagine a lifetime?

3 Layers of the Heart Pericardium = protection, exterior, serous membrane Myocardium = cardiac muscle tissue, involuntary contractions Endocardium = interior layer, lines heart chambers

Blood Flow Pulmonary Circulation No oxygen in blood carries deoxygenated blood away from the heart, to the lung, and returns oxygenated blood back to the heart

Blood Flow continued…. Systemic Circulation Oxygen in blood carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the heart

Heart Valves Allow blood to flow in only one direction Four valves: -- Atrioventricular valves: between atria ventricles • Bicuspid valve or Mitral valve (left) • Tricuspid valve (right) -- Semilunar valves: between ventricle and artery • Pulmonary semilunar valve • Aortic semilunar valve

Chordae Tendineae The chordae tendineae, or heart strings, are cord-like tendons that connect the muscles to the tricuspid valve and the mitral valve in the heart. When the right ventricle of the heart contracts, the blood pressure pushes the tricuspid valve closed and prevents a backflow of blood into the right atrium.

Chordae Tendineae (a.k.a. “heart strings”)