state gov BSSC Laboratory Assistant Mock Test Series 2025 Biology Human Physiology Circulatory System
Choose the correct statements among the following:-
1
AVN is the pace maker that generates action potential and initiates the atrial systole
2
During each cardiac cycle, the 'lub' sound is due to closure of semilunar valves
3
Stroke volume in each cardiac cycle is approximately 170 ml of blood
4
The opening between right atrium and right ventricle is guarded by tricuspid valve