Mechanical events of the heart

Question 1

Mechanical events of the heart

Answer 1

1. Late diastole - both sets of chambers are relaxed and ventricles fill passively
2. Atrial systole- atrial contraction forces a small amount of additional blood into ventricles
3. Isovolumic ventricular contraction- first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves
4. Ventricular ejection- as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected
5. isovolumic ventricular relaxation- as ventricles relax; pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed.