The Heart Valves

Heart valves are flap-like structure located within the heart chambers. Valves allow proper flow of blood through the heart in one direction. It controls the blood flow by opening and closing during heart contraction. Valves movements are controlled by blood pressure and some muscle contraction. If valve doesn't close properly and there is blood leaking backward it is called Mitral Valve prolapse. Mitral valve prolapse is a common heart valve disease causing irregular heart beat or arrhythmia.

There are two kinds of valves, the Atrioventricular Valves and Semilunar Valves. 

Atrioventricular Valves or also known as Cuspid valves are located between the atria and ventricles. They primarily prevent blood back-flow from the ventricles (lower portion of the heart) and atrium (upper portion of the heart). Atrioventricular Valves are connected to the ventricles by cone-shaped muscular pillars called papillary muscles. Papillary muscles are attached by chordae tendineae – a strong thin and strong connective tissue strings. These strings prevent the valve from invertion. 

The Two Atrioventricular Valves:

  • Tricuspid Valve – Is located between right atrium and right ventricle. It is three-flapped valves that prevents or stops the back-flow of blood between the two chambers. It has three cusps. 
  • Mitral Valve or Bicuspid Valve – Is located in the left side of the heart specifically in the left atrium and left ventricle. It has two cups. 

Semilunar Valves are smaller type of valves that are shaped like moon. They are located between the left ventricle and aorta and pulmonary artery and right ventricle. It permits flow of blood to be forced into the valves and as well as prevents blood back-flow from the arteries into the ventricles. 

The Two Semilunar Valves: 

  • Aortic Valve – It is located between the left ventricle and the aorta. It has three cusps. It primarily prevents the back flow of blood as it is pumped from the left ventricle to the aorta. As the left ventricular increases its pressure due to cardiac contraction the aortic valve opens, allowing flow of blood into the aorta. When the pressure from the left ventricle decreases, the aortic pressure forces the aortic valve to close. 
  • Pulmonary Semilunar Valve – Is sometimes referred to as the pulmonic valve. It is located in between the right ventricle and pulmonary artery and has three cusps. It prevents the backing flow of blood from the right ventricle to the pulmonary artery. The opening and closing of the pulmonary semilunar valves is controlled by pressure produced by right ventricle and pulmonary artery.

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