A valve heart usually allows blood to flow in only one direction through the heart. The four valves commonly represented in the heart of a mammal determine the path of blood flow through the heart. The heart valve opens or closes the liability on differential blood pressure on each side.
The four main valves in the heart are:
- Two atrioventricular (AV) valves, mitral valve (bicuspid valve), and tricuspid valve, located between the upper chamber (atria) and the lower chamber (ventricle).
- Two semilunar valves (SL), aortic valves and pulmonary valves, present in the arteries that leave the heart.
The mitral valve and aortic valve are in the left heart; tricuspid valves and pulmonary valves are in the right heart.
There is also a coronary sinus and an inferior vena cava valve.
Video Heart valve
Structure
Heart valves and chambers are lined with endocardium. The heart valve separates the atria from the ventricles, or the ventricles from the blood vessels. The heart valve is located around the fibrous ring from the heart frame. The valve incorporates a leaflet or cusp , which is pushed open to allow blood flow and which then closes together to seal and prevent backflow. The mitral valve has two valves, while the other has three. There is a nodule at the end of the cusp that makes the seal firmer.
The pulmonary valve has a left, right, and anterior valve. The aortic valve has a left, right, and posterior valve. Tricuspid valve has anterior, posterior, and septum valves; and the mitral valve only has anterior and posterior valves.
Atrioventricular valve
This is the mitral and tricuspid valve, located between the atria and the ventricle and prevents backflow from the ventricle to the atria during systole. They are anchored to the ventricular wall by chordae tendineae, which prevents the valve from inverting.
The chordae tendineae is attached to the papillary muscle which causes tension to further withstand the valve. Together, the papillary muscles and chordae tendineae are known as subvalvular apparatus. The function of the subvalvular apparatus is to keep the valves from prolapse to the atria when they close. Subvalvular equipment has no effect on the opening and closing of the valve, however, which is caused entirely by the pressure gradient in the valve. The strange insertion of chords on leaflet-free margins, however, provides the sharing of systolic stress between chords according to their different thicknesses.
The AV valve closure sounds like lub , the first heart sound (S1). The SL valve closure sounds as dub , the second heart sound (S2).
The mitral valve is also called the bicuspid valve because it contains two leaflets or cusps. The mitral valve gets its name from a resemblance to a bishop's partner (a kind of hat). It is on the left side of the heart and allows blood to flow from the left atrium to the left ventricle.
During diastole, the normally functioning mitral valve opens as a result of increased pressure from the left atrium while filling with blood (preloading). When atrial pressure rises above the left ventricle, the mitral valve opens. Opening facilitates passive blood flow to the left ventricle. The diastole ends with atrial contraction, which spits out 30% of the final blood transferred from the left atrium to the left ventricle. This amount of blood is known as the final diastolic volume (EDV), and the mitral valve closes at the end of the atrial contraction to prevent blood flow reversal.
The tricuspid valve has three leaflets or valves and is on the right side of the heart. It is between the right atrium and the right ventricle, and stops the flow of blood back between the two.
Semilunar valve
Aortic and pulmonary valves are located at the base of the aorta and pulmonary stems. This is also called the "semilunar valve". Both of these arteries receive blood from the ventricles and their semilunar valves allow blood to be forced into the arteries, and prevent backflow from the arteries into the ventricles. These valves do not have a chorella tendineae, and are more similar to valves in the blood vessels than atrioventricular valves. The closure of the semilunar valve causes a second heart sound.
The aortic valve, which has three cusps, is located between the left ventricle and the aorta. During ventricular systole, pressure increases in the left ventricle and when the pressure is greater than the pressure in the aorta, the aortic valve opens, allowing blood to exit from the left ventricle to the aorta. When the ventricular systole is over, the pressure in the left ventricle decreases rapidly and pressure in the aorta forces the aortic valve to close. The closure of the aortic valve supports the A2 component of the second heart sound.
The pulmonary valve (sometimes referred to as the pulmonary valve) lies between the right ventricle and the pulmonary artery, and has three cusps. Similar to the aortic valve, the pulmonary valve opens in the ventricular systole, when the pressure in the right ventricle rises above the pressure in the pulmonary artery. At the end of the ventricular systole, when pressure in the right ventricle falls rapidly, pressure in the pulmonary artery will close the pulmonary valve. Pulmonary valve closure accounts for the P2 component of the second heart sound. The right heart is a low pressure system, so the P2 component of the second heart sound is usually softer than component A2 of the second heart sound. However, it is physiologically normal for some young people to hear the two separate components during inhalation.
Development
In the developing heart, the valve between the atria and the ventricle, the muscle valve and the tricuspid valve, develops on both sides of the atrioventricular canal. The upward extension of the ventricular bases causes the canal to be invaginated into the ventricular opening. The initialized margin forms the basis of the lateral valve of the AV valve. Central and septum poles evolved from the downward extension of the intermedium septum.
Semilunar valves (pulmonary and aortic valves) are formed from four thickening at the end of the heart of the trunk arteriosus. These thickenings are called endocardial pillows. Trunkus arteriosus is initially a single outlet of the embryonic heart that later divides into the aorta and upward lung stem. Before splitting, four thickening occurs. There is an anterior, posterior, and two lateral thickening. The septum begins to form between what will later become the aorta and the asymptomatic pulmonary tract. When the septum is formed, two lateral thickenings are divided, so that the aorta rises and the pulmonary trunk has three thickening each (anterior or posterior, and half of each lateral thickenings). The thickened is the origin of three semilunar valve valves. The valve is seen as a unique structure in the ninth week. As they mature, they spin a little when the outer spiral vessels, and move slightly closer to the heart.
Maps Heart valve
Physiology
In general, the heart valve movement is determined using the Navier-Stokes equation, using blood pressure boundary conditions, pericardial fluid, and external loading as constraints. The heart valve movement is used as a boundary condition in the Navier-Stokes equation in determining the fluid dynamics of blood removal from the left and right ventricle to the aorta and lungs.
- The relationship between pressure and flow in the open valve
Penurunan tekanan, , melintasi katup jantung terbuka berhubungan dengan laju aliran, Q, melalui katup:
If:
- Save saved energy
- The stagnant area behind the flyer
- Momentum out is preserved
- Flat speed profile
- Valves with single degrees of freedom
Typically, aortic and mitral valves are included in valve studies in a single degree of freedom. This relationship is based on the idea of ​​a valve being a single-degree structure of freedom. This relationship is based on the Euler equation.
dimana:
- u = kecepatan aksial
- p = tekanan
- A = luas penampang katup silang
- L = panjang katup aksial
- ? ( t ) = tingkat kebebasan tunggal; kapan
Atrioventricular valve
Clinical interests
Valvular heart disease is a general term that refers to valvular dysfunction, and especially in two forms, either regurgitation, where dysfunctional valves may allow blood flow in the wrong direction, or stenosis, when the valve is narrow.
Regurgitation occurs when the valve becomes insufficient and malfunctions, allowing some blood flow in the wrong direction. This insufficiency may affect any of the valves such as in aortic insufficiency, mitral insufficiency, pulmonary insufficiency and tricuspid insufficiency. Another form of heart valve disease is stenosis, narrowing of the valve. This is the result of the valve becoming thickened and one of the heart valves may be affected, such as in mitral valve stenosis, tricuspid valve stenosis, pulmonary valve stenosis and aortic valve stenosis. Mitral valve stenosis is a common complication of rheumatic fever. Inflammation of the valve can be caused by infective endocarditis, usually a bacterial infection but can sometimes be caused by other organisms. Bacteria can more easily stick to damaged valves. Another type of endocarditis that does not provoke an inflammatory response, is nonbacterial thrombotic endocarditis. This is commonly found on previously undamaged valves. The main heart valve disease is a mitral valve prolapse, which is a weakening of the connective tissue called myxomatous degeneration of the valve. It sees the displacement of the mitral valve valve thickening into the left atrium during systole.
Heart valve disease may be congenital, such as aortic regurgitation or acquired, eg infective endocarditis. Different forms are associated with cardiovascular disease, connective tissue disorders and hypertension. The symptoms of the disease will depend on the affected valve, the type of disease, and the severity of the disease. For example, valvular aortic valve disease, such as aortic stenosis or aortic regurgitation, may cause shortness of breath, whereas tricuspid valve valve deviation can lead to liver dysfunction and jaundice. When heart valve disease is caused by infectious causes, such as infective endocarditis, the affected person may experience fever and unique signs such as nail splinter bleeding, Janeway lesions, Osler nodes and Roth spots. The special complications of valvular disease are the formation of emboli due to turbulent blood flow, and the development of heart failure.
Heart valve disease is diagnosed by echocardiography, which is an ultrasound form. Damaged and damaged heart valves can be repaired, or replaced with artificial heart valves. Causes of infection may also require treatment with antibiotics.
Congenital heart disease
The most common form of valve anomaly is congenital heart defect (CHD), called the bicuspid aortic valve. This results from the two fusion of the valves during embryonic development forming the bicuspid valve instead of the tricuspid valve. This condition is often undiagnosed until calcific aortic stenosis has developed, and this usually occurs about ten years earlier than would develop.
Less common CHD is tricuspid and pulmonary atresia, and Ebstein anomalies. Tricuspid atresia is the absence of a tricuspid valve that can lead to undeveloped or absent right ventricle. Pulmonary atresia is the complete closure of the pulmonary valve. Ebstein's anomaly is the displacement of a septal leaflet from the tricuspid valve causing the larger atrium and the smaller-than-normal ventricle.
History
See also
- Pericardial heart valve
- Bjork-Shiley Valve
References
This article combines text in the public domain of the 20th edition of Gray's Anatomy (1918)
External links
- Mitral Valve Repair at The Mount Sinai Hospital - "Mitral Valve Anatomy"
- 3D heart valves, animations, can be played (Multimedia including Javascript and Flash player required)
- Transcatheter mitral valve implantation: Tendyne
Source of the article : Wikipedia
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