Question

10. Match the columns :
Events in cardiac cycle
Time duratio
(a) 0.3 second
(1) Atrial systole
(2) Atrial diastole
(3) Ventricular systole
(4) Ventricular diastole
(b) 0.5 second
(c) 0.1 second
(d) 0.7 second​

Answer 1

Answer:

Match the columns with the corrected pair

        Time duration            Events in cardiac cycle

• (a) 0.3 second ⇒ (3) Ventricular systole
• (b) 0.5 second ⇒ (4) Ventricular diastole
• (c) 0.1 second ⇒ (1) Atrial systole
• (d) 0.7 second ⇒ (2) Atrial diastole

Explanation:

• Cardiac cycle depends on the heart rate occurring every 60 seconds. Suppose if the heart rate is 60 per 60 seconds, then the cardiac cycle becomes 1 second. This clearly means that both cardiac cycle and heart rate are inversely related. For example, if heart rate becomes about 180 beats per 60 seconds, then cardiac cycle will reduce to 0.25 second. In a normal person, one cardiac cycle's duration is 0.8 second.
• During the cardiac cycle, there is contraction (i.e. systole) and relaxation (i.e. diastole) in atria first and then in the ventricle.
• This particularly points out towards the fact that at first there will be atrial systole (0.1 second), followed by atrial diastole (0.7 second). This completes one cardiac cycle which is of 0.8 second.
• After the completion of atrial diastole, ventricular systole (0.3 second) takes place, followed by ventricular diastole (0.5 second).
• In a cardiac cycle, atrial systole and ventricular systole will never occur together.
• But a fraction of atrial diastole and ventricular diastole occur concurrently. This means that a fraction of atrial diastole will take place when the ventricles are present in their diastolic phase.