17. Short answer questions VII

The complete events of cardiac cycle last for \(0.8 \ sec\). What is the timing for each event?

 

a. The sequence of events occurring from the beginning to the completion of one heartbeat is called the .

 

b. The cardiac cycle consists of one cycle of  and relaxation of cardiac muscle.

 

c. During , the auricles contracts due to a wave of contraction, stimulated by the SA node. The bicuspid and tricuspid valves open, forcing blood into the ventricles. It lasts for  seconds.

 

d. During , ventricles contract due to a wave of contraction, which is stimulated by the SA node.  Bicuspid and tricuspid valves close immediately, producing the first heart sound. When the ventricles complete their contraction, the blood flows into the pulmonary trunk and aorta as the semilunar valves open. The duration is  seconds.

 

e. During , relaxation of ventricles occurs, and the semilunar valves close. Next, the tricuspid and bicuspid valves open, and blood flows from the atria into the ventricles. The ventricular diastole lasts for  seconds.