Question

Isovolumetric contraction:

Question options:
A)occurs only in people with heart valve defects.
B)refers to the short period during ventricular systole when the ventricles are completely closed chambers.
C)occurs immediately after the semilunar valves close.
D)occurs while the AV valves are open.

Answer 1

Isovolumetric contraction is a phase during the cardiac cycle where the ventricles contract without a change in volume due to the closure of both atrioventricular and semilunar valves until the pressure within the ventricles is sufficient to eject blood.

Step-by-step explanation:

Isovolumetric contraction, also known as isovolumetric contraction, is a phase in the cardiac cycle where the ventricles contract but do not change in volume. This occurs because, although the muscles in the ventricle contract and the pressure rises, it is not yet high enough to push open the semilunar valves and eject blood from the heart. During this time, the pressure in the ventricles becomes higher than in the relaxed atria, leading to the closure of the tricuspid and mitral valves (atrioventricular valves).

With both the atrioventricular and semilunar valves closed, the chamber is sealed, and thus, despite the increase in pressure due to contraction, there is no ejection of blood and the volume remains unchanged. Once the pressure is high enough, the semilunar valves will open, allowing for the ejection of blood and marking the end of the isovolumetric contraction phase.