Final answer:
A valve that doesn't close properly during systole can cause a heart murmur due to regurgitation. This is often a result of valve prolapse, and can lead to conditions named according to the affected valve, such as mitral or tricuspid insufficiency.
Step-by-step explanation:
If a valve doesn't close properly, blood leaks back during systole and causes a heart murmur. This condition is often due to a prolapsed valve, where the cusps are forced backward, potentially because of damaged or broken chordae tendineae. This improper closure of the valve disrupts the normal directional flow of blood, leading to regurgitation, where the blood flows backward instead of forward. This can be detected audibly as a heart murmur using a stethoscope.
During the process of systole, if the mitral or tricuspid valve does not close properly, the increasing pressure in the ventricles can push blood back into the atria, which should be closed off during this phase, resulting in what is known as isovolumic contraction. Failure of these valves can also lead to specific types of insufficiency, like mitral or tricuspid insufficiency, depending on which valve is affected.