Question

Which of these occurs during the atrial systole?

(a) Both atria contract simultaneously

(b) Action potential is generated by the AVN initially

(c) Tricuspid valve closes

(d) The semilunar valves remain open

This question was posed to me in an interview for job.

This is a very interesting question from Human Circulatory System in chapter Body Fluids and Circulation of Biology – Class 11

Answer 1

Right answer is (a) Both atria contract simultaneously

Easiest explanation: During the atrial systole, both the atria contract simultaneously while the ventricles remain relaxed. It occurs due to the action potential generated by the SAN. The tricuspid and bicuspid valves open.