Answer to Question #106701 in Human Anatomy and Physiology for mo

Question

If 1st heart sound is from the closure of the AV valves and the 2nd heart sound from the closure of the semilunar valves, why can we hear both sounds in all 4 areas?

Answer 1

The pumping of the heart is caused by alternating contradictions and relaxation of the myocardium .These contradictions are stimulated by electrical impulses from a neutral peacemaker .The sinoartrial or S-a node causes the two artria to contract,forcing blood into the ventricles.Contradiction of the ventricles is controlled by impulses from AV valve located at the junction of the two atria.After the contraction ,the ventricles relax ,and pressure within them falls.