What is the approximate time required for a heart-beat ? A)0.5 second B)0.8 second C)0.5 minute D) 1.0 minute
Option B) The heart has an increasing rhythmic activity. It pumps blood by its contraction and relaxation. The contraction of the heart is called systole and the relaxation is called diastole. The contraction and relaxation together constitute the heart beat. The heart beats at the rate of 72 beats per minute. There are 3 main events in the cardiac cycle. Auricular Systole (Atrial Systole) phase involves the contraction of the 2 auricles, pushing the blood into the respective ventricles. The atrial systole takes 0.1 second. Ventricular Systole takes about 0.3 seconds. Ventricular systole is followed by ventricular diastole. The auricles are already in diastole, so all the chambers of the heart are in diastole. A complete cardiac diastole takes only 0.4 seconds. An entire cardiac cycle is completed in 0.8 seconds.
