The heart is enclosed in a pericardial sac lined with parietal layers of a serous membrane. The visceral layer of the serous membrane forms the epicardium. Four valves regulate and support blood flow through and out of the heart. Blood can only flow in one direction – like a car that must always be kept moving. Each valve consists of a group of folds or spikes that open and close as the heart contracts and expands. There are two atrioventricular (AV) valves located between the atrium and ventricle on both sides of the heart: the tricuspid valve on the right has three bumps, the mitral valve on the left has two. The other two valves regulate blood flow to the heart. The aortic valve controls blood flow from the left ventricle to the aorta. The pulmonary valve controls blood flow from the right ventricle through the lung shaft into the pulmonary arteries. Prolapse – When the heart valve leaflets do not close properly The valves are made up of strong, thin tissue lobes called leaflets or bumps. The pulmonary valve (sometimes called the pulmonary valve) is located between the right ventricle and the pulmonary artery and has three ends.
Similar to the aortic valve, the pulmonary valve in the ventricular systole opens when the pressure in the right ventricle increases on the pressure in the pulmonary artery. At the end of the ventricular systole, when the pressure in the right ventricle decreases rapidly, the pressure in the pulmonary artery closes the pulmonary valve. The closure of the pulmonary valve contributes to the P2 component of the second cardiac sound. The right heart is a low-pressure system, so the P2 component of the second cardiac sound is usually softer than the A2 component of the second cardiac tone. However, in some adolescents, it is physiologically normal for the two components to be separated during inhalation. Heart valve disease is diagnosed by echocardiography, a form of ultrasound. Damaged and defective heart valves can be repaired or replaced with artificial heart valves. Infectious causes may also require antibiotic treatment.
 The task of the valves is to move blood through the heart. When both ear chambers contract, the tricuspid and mitral valves open, allowing blood to move to the ventricles. When both ventricular chambers contract, they force the tricuspid and mitral valves to close when the pulmonary and aortic valves open. Blood that is supposed to leave the ventricles to reach the body is designed to be prevented from flowing in the wrong direction through the parts of the aortic and pulmonary valves called bumps. The bumps help the valves create a tight seal that supports blood flow in the right direction. The muscular wall of the heart promotes contraction and dilation. Every contraction and relaxation is a heartbeat. Ventricular contractions, called systoles, force blood out of the heart through the lungs and aortic valves.
Diastole occurs when blood flows from the atria to fill the ventricles. Chordae tendineae is attached to the papillary muscles that cause tension to better hold the valve. Together, the papillary muscles and chordae tendineae are called the subvalvular apparatus. The function of the subvalvular device is to prevent prolapse valves in the atria when they close.  However, the subvalvular device does not affect the opening and closing of the valves, which is completely caused by the pressure gradient via the valve. However, the special insertion of chords on the free edge of the leaflet ensures a systolic sharing of the constraints between the chords according to their different thickness.  The left side of the heart receives oxygen-rich blood from the lungs and then pumps blood through the aorta into the rest of the body`s tissues. The tricuspid valve has three leaves or bumps and is located on the right side of the heart. It is located between the right atrium and the right ventricle and stops blood reflux between the two.
The mitral valve has only two leaflets; The aortic, pulmonary and tricuspid valves have three. The leaves are attached to and supported by a ring of hard fibrous tissue, called a ring. The ring helps to maintain the correct shape of the valve. Regurgitation – If the valves do not close completely, blood can flow backwards. This is called regurgitation. When the ventricles contract, the atrioventricular valves close to prevent blood from flowing back into the atria. When the ventricles relax, the crescent-shaped valves close to prevent blood from flowing back into the ventricles. The heart is divided into a right side and a left side, separated by a septum. Each side has an atrium (which absorbs blood when it enters) and a ventricle (from which blood is pumped). The heart has a total of four chambers: right atrium, right ventricle, left atrium and left ventricle. The four valves in the heart of mammals are two atrioventricular valves that separate the upper atria from the lower ventricles – the mitral valve in the left heart and the tricuspid valve in the right heart. The other two valves are located at the entrance of the arteries that leave the heart, these are the crescent-shaped valves – the aortic valve on the aorta and the pulmonary valve on the pulmonary artery.
The valves and heart chambers are lined with endocardium. Heart valves separate the atria from the ventricles or ventricles of a blood vessel. The heart valves are located around the fibrous rings of the cardiac skeleton. Valves contain valves called leaflets or bumps, similar to a duck-billed valve or a floating valve, that are opened to allow blood flow and then come together to seal and prevent reflux. The mitral valve has two bumps, while the others have three. At the ends of the bumps there are nodules that make the joint more tight. The mitral valve and tricuspid valve are located between the atria (upper ventricles) and the ventricles (lower ventricles). The heart has four valves. The mitral valve, tricuspid valve, pulmonary valve and aortic valve. Mitral and tricuspid valves, also known as atrioventricular valves, are located between the upper chambers of the heart, the atria, and the lower chambers of the heart, the ventricles. The aortic and pulmonary valves are located between the ventricles and arteries that emerge from the heart.
These valves are also known as crescent-shaped valves. The second part of the pumping phase begins when the ventricles are full of blood. Electrical signals from the SA node move along a path from the cells to the ventricles, causing them to contract. This is called systole. Since the tricuspid and mitral valves are tightly closed to prevent blood reflux, the pulmonary and aortic valves are open. While blood from the right ventricle is pushed into the lungs to absorb oxygen, oxygen-rich blood flows from the left ventricle to the heart and other parts of the body. While the heart and lungs are the largest organs of the circulatory system, the blood vessels are the longest. This vast network of stretchy tubes circulates blood throughout the body. From end to end, your body`s blood vessels would span 60,000 miles. That`s more than 21 road trips between New York and Los Angeles! 4. Closed pulmonary and aortic valvesWhen the right ventricle contracts and begins to relax, the pulmonary valve falls into place.
This prevents blood from flowing back into the right ventricle. When the left ventricle contracts and begins to relax, the aortic valve closes. This prevents blood from flowing back into the left ventricle. 8. Pulmonary veins: Carry oxygen-rich blood from the lungs to the left atrium of the heart. The right side of the heart collects oxygen-depleted blood and pumps it through the pulmonary arteries into the lungs, allowing the lungs to refresh the blood with a supply of fresh oxygen. In the developing heart, valves develop between the atria and ventricles, bicuspid and tricuspid valves, on both sides of the atrioventricular canals.  The upward expansion of the bases of the ventricles causes the canal to penetrate the cavities of the ventricle. The single-flicker edges form the rudiments of the side ends of the AV valves. The middle and septal bumps develop from the downward expansion of the septum intermedium. The crescent-shaped valves (the pulmonary and aortic valves) are formed by four thickenings at the central end of the arterial trunk.  These thickenings are called endocardial pillows.
[Citation needed] The arterial trunk is originally a single flow channel of the embryonic heart, which then divides into the ascending aorta and lung shaft. Before it is divided, four thickeners occur. There are front, rear and two side thickeners. A septum begins to form between what later becomes the ascending aorta and the pulmonary pathways. When the septum is formed, the two lateral thickenings are divided so that the ascending aorta and lung shaft each have three thickenings (one anterior or posterior and half of the lateral thickenings each). Thickening is the cause of the three ends of the crescent valves. .