Question

Atrial systole lasts for in cardiac cycle.
A. 0.1 second
B. 0.3 second
C. 0.5 second
D. 0.7 second

Answer 1

Atrial systole, diastole ventricular systole, and diastole is made up by the cardiac cycle. In humans the normal heart beats for about 72 times per minute and the cardiac cycle is 0.8 second approximately. And the time of cardiac diastole 0.4 second and 0.3 second for the ventricular systole.

Complete answer:
One beat is repeated in the same order in the next beat during the change that occurred in the heart. And cyclic repetition during this process is known as cardiac cycle and the normal human heart rate is 0.8 second per minute. Diastole and systole are the two cycles of the cardiac activity.
In the systole there are two events occurring diastole and systole representative during the left and right ventricle contract and eject blood into the pulmonary artery and aorta. During the process occurred in the systole the pulmonary valves and aortic Valve opens to permit ejection into the pulmonary and aorta artery. During the systole atrioventricular valves are closed and no blood enters the ventricles but the process of entering the continuous blood into the atria through the vena. It is also called atrial systole and cardiac cycle is initiated by auricular systole and duration of the auricular systole is 0.1 second.

Therefore the correct option is (A).

Note: Aortic and pulmonic valves open and permit ejection into the pulmonary artery and aorta during the systole process. But during systole no blood enters the ventricles and continues into the pulmonary veins, cavae and vena because of that atrioventricular valves are closed.