Structure and Blood Flow The Heart Structure and Blood Flow

Objectives 1. Be able to identify the structures of the heart. 2. Be able to discuss the functions and location of valves in the heart. 3. Be able to define pulmonary and systemic circulation. 4. Be able to explain the sequence of blood flow through the heart. 5. Be able to explain coronary circulation and coronary heart disease.

BCS Brachiocephalic trunk Carotid artery Subclavian artery

Valves Keep blood from flowing back into a chamber of the heart Located by entrance and exit of ventricles

Atrioventricular Valves Separates atrial chambers from ventricles Prevents backflow of blood into atria Bicuspid (Mitral) on left side Tricuspid on right side Chordae tendineae- string-like structures that attach AV valves to the wall of the heart

Semilunar Valves Between ventricles and large arteries that carry blood away from the heart when contraction occurs Since ventricles contract together (atria also contract together) the two semilunar valves open and close at the same time

Pulmonary semilunar valve- at beginning of pulmonary artery (blood going to lungs); right ventricle Aortic semilunar valve- at beginning of aorta; allows blood to flow out of the left ventricle up into the aorta but prevents backflow

Right Left “BALL” ENTRANCE: Atrioventricular Valves Tricuspid Bicuspid (Mitral) EXIT: Semilunar Valves Pulmonary Semilunar Aortic semilunar

Circulation Pulmonary circulation-movement of blood from right ventricle to lungs Systemic circulation-movement of blood from left ventricle to body

Sequence of Blood Flow 1. Oxygen poor blood from vena cavas to right atrium 2. Pass tricuspid valve to right ventricle 3. Pass pulmonary semilunar valve to pulmonary artery to lungs

4. Oxygen-rich blood from lungs via pulmonary vein to left atrium 5. Pass bicuspid valve to left ventricle 6. Pass aortic semilunar valve to aorta

7. From aorta throughout body via arteries, capillaries, and veins back to the heart

Coronary Circulation and Coronary Heart Disease Blood, which supplies oxygen and nutrients to the myocardium of the heart, flows through the right and left coronary arteries Blockage of blood flow through the coronary arteries can cause myocardial infarction (heart attack)

Coronary Circulation and Coronary Heart Disease Atherosclerosis (type of “hardening of arteries” in which lipids build up on the inside wall of blood vessels) can partially or totally block coronary blood flow Angina pectoris—chest pain caused by inadequate oxygen to the heart