83. how do the valves in the heart operate
Four heart valves control the flow of blood through the heart. They act as one-way doors, opening to let blood exit or enter a chamber, then closing to keep blood from flowing backward. 1  The tricuspid valve controls blood flow from the right atrium to the right ventricle. Then they shut to keep blood from flowing backward. When the heart's valves open and close, they make a lub-DUB sound that a doctor can hear using a stethoscope. 1  The first sound—the lub—is made by the mitral and tricuspid valves closing at the beginning of systole (SIS-toe-lee). 2  Systole is when the ventricles contract, or squeeze, and pump blood out of the heart. There are four chambers in your heart and the valves make sure that the blood flows through them in one direction. The two large blood vessels that leave the heart also have valves to make sure that the blood does not go back into the heart once it has been pumped out. 1  Find out more about how your heart works. At the same time, the aortic valve opens to allow blood to flow from the left lower chamber into the aorta. This aorta carries oxygen-rich blood to the body. As the contraction ends, the pulmonary and aortic valves shut tightly. This stops blood from flowing backward into the lower chambers. The heart has two upper chambers called the right and left atria and two lower chambers called the right and left ventricles. On the right side of the heart, blood lacking oxygen returns from the body into the right atrium. 1 The mitral (MI-trul) valve is in the left side of the heart, between the left atrium and the left ventricle. 2  The aortic (ay-OR-tik) valve is in the left side of the heart, between the left ventricle and the entrance to the aorta. 3  This artery carries blood from the heart to the body. There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood. As the heart muscle contracts and relaxes, the valves open and shut, letting blood flow into the ventricles and atria at alternate times. If the valve does not close properly, it will allow blood to leak backwards. This is called valve incompetence or regurgitation or a leaky valve. This can put extra strain on your heart and may mean that your heart has to do extra work to pump the required volume of blood. The main causes of heart valve disease are: 1  being born with an abnormal valve or valves (congenital heart disease). 2  having had rheumatic fever. 3  cardiomyopathy-a disease of the heart muscle. 4  damage to the heart muscle from a heart attack. Heart Valves. Four valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart. 1  The tricuspid (tri-CUSS-pid) valve is in the right side of the heart, between the right atrium and the right ventricle.
Four heart valves control the flow of blood through the heart.