How a hydrogen fuel cell generates electricity. The following step-by-step explanation describes how a fuel cell generates the electricity used to power the vehicle: 1. Hydrogen is supplied to the anode (negative) side of the fuel cell. 2. Hydrogen molecules activated by the anode catalyst release electrons. 3. The electrons travel from the anode to the cathode (positive) side of the fuel cell, creating an electrical current. 4.
A. A heart murmur is a sound that is created by inadequate blood flow through the heart and its large vessels, for example the aorta. Some are born with a heart murmur and further testing doesn't reveal any significant problem.This is called a physiological murmur.eart murmur Cardiology An auscultatory sound of cardiac or vascular origin, usually caused by an abnormal flow of blood in the heart due to structural defects of the valves or septum; murmurs may be benign or pathological.
Heart murmurs are heart sounds produced when blood flows across one of the heart valves that is loud enough to be heard with a stethoscope. There are two types of murmurs.A functional murmur or  physiologic murmur is a heart murmur that is primarily due to physiologic conditions outside the heart. Other types of murmurs are due to structural defects in the heart itself. Functional murmurs are benign (an  innocent murmur ).Murmurs may also be the result of various problems, such as narrowing or leaking of valves, or the presence of abnormal passages through which blood flows in or near the heart.Such murmurs, known as pathologic murmurs, should be evaluated by an expert.urmurs may also be the result of various problems, such as narrowing or leaking of valves, or the presence of abnormal passages through which blood flows in or near the heart. Such murmurs, known as pathologic murmurs, should be evaluated by an expert.