Question

In cardiac cycle, maximum time is taken by
A. Atrial systole
B. Atria diastole
C. Ventricle systole
D. Ventricle diastole

Answer 1

Hint: Cardiac cycle is the cycle of flow of blood in and out of the heart. Performance of the human heart completes the cardiac cycle. Diastole (relaxation) and systole (contraction) of heart muscles causes heartbeat. Time taken to complete one cardiac cycle is 0.8 seconds. Cardiac muscles contract and relax in a rhythmic manner. Atrial and ventricular systole and diastole play a major role in cardiac cycle.

Complete step by step answer: Cardiac cycle involves rhythmic movement of heart muscles. During Systole blood from ventricles propelled into and out. During diastole, blood fills the emptied ventricles. Cardiac cycle or one complete heart involves systole followed by diastole.
Atrial systole:-when the atrial systole begins ventricles are already 70 percent filled because of passive flow of atria. Contraction of atria causes atrioventricular valves to open completely and ventricles to fill. Atrial systole lasts for about 0.1 seconds.
Atrial diastole, is the phase in which atria are relaxing under suction, dilating and filling. It lasts for about 0.4 seconds.
Ventricular systole begins when ventricles begin to contract, ventricular pressure becomes greater than atrial pressures. Semilunar valves are pushed open when pressure in ventricles increases and exceeds the arterial pressure. Ventricular systole causes ejection of blood into large arteries and it lasts to about 0.3 seconds.
 During ventricular diastole two ventricles are relaxing from contraction then fills up the blood. Ventricle diastole lasts for about 0.5 seconds.
As we have discussed above, ventricle diastole lasts for a longer time in a cardiac cycle.
So, the option D is correct.

Note: Heartbeats of the average adult person at rest range from 65 to 75 per minute. One heartbeat is the same as one complete cardiac cycle. Heartbeats sounds like a lub dub. Heart weighs between 7 and 15 ounces. Heartbeats around ten thousand times in a day. Heart pumps 2000 gallons of blood in a day. New born babies have the fastest heartbeat. Heart attacks may occur due to many reasons it mostly occurs in the morning.