Cardia Cycle

Systole

contraction

diastole

relaxtion

End-diastolic volume

amount of blood after filling up the ventricle. (closing of valve)

end-systolic volume

amount of blood after ejecting it from the ventricle

end-diastolic volume in mL

135 mL

end-systolic volume in mL

65 mL

Stroke volume

difference between EDV & ESV is 70 mL

Isovolumetric Contraction

Early phase of ventricular systole

Ventricular walls contract; however, blood has not been ejected yet because all heart valves are closed

Isovolumetric Relaxation

Ventricles relax after systole without any change in blood volume. Waits for the next filling stag

Cardiac Cycle

1. 1. Blood enters the atria and may go into the ventricles

2. 2. Atria contract to force the last bit of blood into the ventricles; A-V valves close because ventricular pressure is higher than atrial pressure

3. 3. Ventricles do isovolumetric contraction

4. 4. Ventricular pressure exceeds aortic/pulmonary pressure; the semilunar valves open

5. 5. Semilunar valves close when aorta/pulmonary pressure is high. Ventricles undergo isovolumetric relaxation

6. 6. When ventricular pressure falls below atrial pressure, A-V valves open and blood go into ventricles

7.