Published by: Nuru
Published date: 06 Jul 2021
The human heart is a muscular organ which is located between two lungs in the thorax. About two-third part of it lies towards the left thorax and one-third part lies towards the right thorax. The size of the heart is equal to the owner’s close fist. It consists of four chambers. The upper two chambers are called auricles and the lower two chambers are called ventricles. The right and left part of the heart is separated by a wall which is known as the septum. It prevents the direct flow of blood from the left part to the right and vice versa.
The heart is externally surrounded by a thin membrane which is known as the pericardium.
The fluid present between the pericardium and the heart is known as pericardial fluid. It protects the heart from external shock and injury.
The function of the valve in the heart is to allow the flow of blood in a fixed direction. There are four types of valves in the heart, they are:
1. Tricuspid valve
The valve lies in between the right auricle and the right ventricle. It blocks the backflow of blood from the right ventricle to the right auricle when ventricles are connected.
2. Bicuspid valve (Mitral valve)
It lies between the left auricle and the left ventricle. It blocks the overflow of blood from the left ventricle to the left auricle, when ventricles are contracted.
3. Pulmonic valve
It lies between the right ventricle and the pulmonary artery. It is half-moon-shaped. It blocks the backflow of blood from pulmonary arteries to the right ventricle, when the ventricles are relaxed.
4. Aortic valve
It is also a half-moon-shaped valve that is located in the opening of the left ventricle and aorta. It blocks the backflow of blood from the aorta to the left ventricle, when ventricles are relaxed.
The blood vessel which carries impure blood from the upper part of the human body to the right auricle is known as the superior vena cava.
The blood vessel which carries impure blood from the lower part of the human body to the right auricle is known as inferior vena cava.
The blood vessel which carries the blood from the heart to the lungs is known as the pulmonary artery. It carries impure blood.
The blood vessel which carries blood from the lungs to the heart is known as a pulmonary vein. It carries pure blood.