If the mitral valve were insufficient would you expect to he

If the mitral valve were insufficient, would you expect to hear the murmur (of blood flowing through the value that should be closed) during ventricular systole or diastole? Review the cardiac cycle. Blood flow through the heart is controlled entirely by pressure changes in the chambers. Blood flows down a pressure gradient through any available opening(valves) The pressure changes inside the chambers of the heart are directly related to the alternating contraction and relaxation of the myocardium and cause the heart valves to open, which keeps the blood flowing in a forward direction. When is ventricular pressure the highest? When is pressure in the heart the lowest? (The entire heart is in total relaxation. Blood returning from the systemic or pulmonary circulation is flowing passively through the atria and the open AV valves into the ventricles.) Define cardiac output, and give the formula. Calculate the cardiac output for an average adult with a heart rate of 75-beats/min and stroke volume of 70 ml/beat.

Solution

Ans 29.

Blood flows from right atrium to right ventricle via mitral valve. When ventricles are full of blood, then mitral valve is closed. This disallows the movement of blood back into the right atrium.

Now, if the mitral valve is insufficient, it means that it has a defect and is not able to close properly. At this time, when ventricles squeeze to push blood further out of the ventricle, then adequate pressure will not be created for squeezing, due to partly open/open mitral valve. So, you will not hear the murmur sound of movement of blood.

Please note that the murmur sound is due to the pressure created in ventricle after filling up of blood.