Question

How do ventricles enter into the state of isovolumetric contraction?

Answer 1

Isovolumetric contraction

1. Isovolumetric contraction is a short period of time when all the four valves of the heart are closed due to the pressure created in the chambers of the heart at the beginning of ventricular systole.
2. During isovolumetric contraction, the blood volume in all four ventricles remains the same.
3. The atrioventricular valves close at the beginning of ventricular systole which causes the pressure inside the ventricles to exceed the corresponding atrium.
4. Simultaneously, the pressure is insufficient to open the semilunar valves.
5. As a result, the ventricles are in a condition of isovolumetric contraction.
6. The isovolumetric contraction triggers the left ventricular pressure to build above the atrial pressure.
7. This closes the mitral valve and generates the first heart sound.