NEETZoologyBody Fluids and Circulation
What causes the semilunar valves to open?
Options
- AThe ventricular pressure increase
- BThe closure of the tricuspid and bicuspid valves
- CThe relaxation of the ventricles
- DThe backflow of blood into the atria
Correct answer
A. The ventricular pressure increase
Step-by-step solution
As the ventricular pressure increases further, the semilunar valves guarding the pulmonary artery (right side) and the aorta (left side) are forced open, allowing the blood in the ventricles to flow through these vessels into the circulatory pathways. The ventricles now relax (ventricular diastole) and the ventricular pressure falls causing the closure of semilunar valves which prevents the backflow of blood into the ventricles..