Question

Which of the following is the correct sequence of events regarding the cardiac cycle? Multiple Choice Isovolumic contraction, isovolumic relaxation, ejection, passive ventricular filling, active ventricular filling Isovolumic relaxation, isovolumic contraction, ejection, passive ventricular filling, active ventricular filling Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling Isovolumic contraction, ejection, isovolumic relaxation, active ventricular filling, passive ventricular filling Ejection, isovolumic relaxation, passive ventricular filling, Isovolumic contraction, active ventricular filling

Answer 1

Answer:- Correct sequence of events regarding cardiac cycle is as follows:- Isovolumic contraction - Ejection - Isovolumic relaxation - active ventricular filling - Passive ventricular filling. Thus, option 4 is correct.

Explanation:- A cardiac cycle starts with contraction of the atria (systole) and ends with ventricular relaxation (diastole).

At the beginning of the cardiac cycle, both the atria and ventricles are relaxed (diastole). Initial phase is ventricular systole also known as isovolumic contraction. And second phase of ventricular systole is the ventricular ejection phase. Ventricular filling occurs during diastolic phase. In Isovolumetric relaxation, the first part of rapid early filling are active, energy-requiring processes which is about 70% of ventricular filling where as final 25% of filling occurs during ventricular diastole passively.