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:SemilunarValves

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