stages of the cardiac cycle. Your explanation should name the four chambers, the four heart valves, the major vessels entering and exiting the heart, and the two circuits of blood flow in the cardiovascular system.
4 chambers of the heart: Left+ right atria, left+right ventricles
4 valves of the heart:
Atrioventricular: Left= mitral, right=tricuspid
Semilunar: left=aortic, right=pulmonary OPEN when ventricles contract
Two circuits of blood flow: right-pulmonary circuit-right ventricle to lungs(via pulmonary arteries)-collects oxygen-returns to left side of the heart via pulmonary veins
Left-systemic-pumps blood from left ventricle-tissues of body (via aorta and its many branches)-delivers nutrients-returns to the right side of the heart via inferior vena cava, superior vena cava, and coronary sinus
Stages of cardiac cycle:
Heart is relaxed: atrial and ventricular diastole
AV valves open: Passive movement of blood (70 percent) from the atria to the ventricles due to gravity b/c the valves are hanging open during relaxation
Atrial syostole: squeeze the last of the blood (30) into the ventricles
Ventricular syostole: closes AV valves, opens SL valves
Blood is pushed back out of the heart
Ventricular distole-back to the start
SL valves close