Monday, September 16, 2019

Different Heart Chambers and Valves

Chambers of the Heart:
The heart has four chambers. Those are listed in the below:
  1. Right atrium,
  2. Right ventricle,
  3. Left atrium,
  4. Left ventricle.
The two atria are separated from each other by a vertical septum is called interventricular septum. The right atrium communicates with the right ventricle through the right atrioventricular orifice, which is guarded by three cusps. The left atrium communicates with the left ventricle through the atrioventricular orifice, which is guarded by two cusps. 
Human heart chamber and valves
Fig: Human heart chamber and valves
1. Right Atrium:
The right atrium is the right upper chamber of the heart. It receives venous blood from the whole body through three veins:

Superior vena cava and inferior vena cava: Together these veins deliver blood from the body to the heart.

Coronary sinus, that returns blood from the walls of the heart itself.

The right atrium pumps blood to the right ventricle through the right atrioventricular or tricuspid opening.

Internal Features of Right Atrium:
All the internal features of the right atrium have presented in the below:
  • The interior of the right atrium is divided into two continuous spaces: smooth-walled posterior part and rough-walled anterior part. Internally, this division is marked by the crista terminals, which is a smooth, muscular ridge. It corresponds to sulcus terminals externally.
  • The rough anterior part presents musculi pectinati, which fan out from the crista terminals like the: teeth of the comb”.
  • The interatrial septum that separates the right atrium from the left atrium, presents fossa ovalis. It is a depression just above the orifice of the inferior vena cava.
2. Right Ventricle:
The right ventricle is a triangular chamber that receives blood from the right atrium and pumps it to the lungs through the pulmonary trunk and pulmonary arteries.

Internal Features of Right Ventricle:
It includes-
  • The outflow tract of the right ventricle that leads to the pulmonary trunk is the conus arteriosus (Infundibulum). This area is smooth.
  • Trabeculae carnae are irregular muscular ridges.
  • Papillary muscles. The three papillary muscles are lying among the trabeculae carnae. These are- anterior, posterior and septal.
3. Left Atrium:
The left atrium is a quadrangular chamber which is situated posteriorly. It receives oxygenated blood from the lungs through four pulmonary veins and pumps it to the left ventricle through the left atrioventricular orifice (mitral orifice).

4. Left Ventricle:
The left ventricle is a conical chamber. It is longer than the right ventricle and has the thickest layer of the myocardium.

Internal Features of Left Ventricle:
It includes-
  • Trabeculae carnae,
  • Two papillary muscles- Anterior and posterior,
  • Two orifices- left atrioventricular or mitral orifice and aortic orifice.
Valves of the Heart:
The valves of the heart include-

1. Atrioventricular valves: Right atriventricular valve (tricuspid valve) and left atriventricular valve (Bicuspid or mitral valve),

2. Semilunar valves: Aortic valve and pulmonary valve.

There are 4 (2 pairs) valves in the heart:
  • A pair of atrioventricular valves- In between atria and ventricles.
  • A pair of semilunar valves- At the opening of blood vessels arising from the ventricles, namely aorta and pulmonary artery.