The human heart is slightly bigger than the size of one's fist. It is situated at a very safe place which is between the cage bones, i.e., in the centre of the chest. It is slightly on the left side of the chest but in rare cases, it can be found on the right side. The heart is responsible for the blood flow to every single part of the body through constant contraction and relaxation of cardiac muscles. This is the reason why we hear rhythmic beats all the time. The heart pumps pure blood to different parts of the body and then takes the deoxygenated blood from all the parts to the lungs for oxygenation. Normally in a minute, the heart beats 72 times and pumps around 1,500 to 2,000 gallons of blood per day. Let's check out heart diagram which can help you to understand the functioning of the heart in a better way.

Chambers
The heart is divided into four chambers, left atrium, left ventricle, right atrium and right ventricle. Atriums are the upper chambers of the heart, whereas ventricles are the lower chambers of the heart. All these chambers are separated by a layer of tissues known as the septum. The left side of the chamber is associated with the circulation of the oxygenated blood and the right side receives the deoxygenated blood from various parts of the body.

Valves
There are four valves in the heart namely bicuspid valve, tricuspid valve, pulmonary valve and aortic valve. They help in preventing the backflow of the blood from one chamber to other. This maintains a proper one directional blood flow throughout the process. A bicuspid valve is present between the left atrium and left ventricle whereas tricuspid valve is present between the right atrium and right ventricle. Pulmonary valve behaves as a gate which stops the backflow of blood from right ventricle to the pulmonary artery which takes the deoxygenated blood to the lungs for purification. Lastly the aortic valve, this valve plays an important role in stopping the backflow of the blood from left ventricle to the aorta. Once the blood is transferred to the aorta it supplies the oxygenated blood to different parts of the body.

Blood Vessels
Blood vessels are the blood carriers in a human body. These play a very vital role in the supply of blood to various parts of the body. Blood vessels can be of two types, veins and arteries. All the veins (except pulmonary vein) are involved in carrying the deoxygenated blood from various parts of the body to the heart whereas all the arteries (except pulmonary artery) are involved in supplying oxygenated blood from the heart to different parts of the body.

Functioning of the Heart

After getting familiar with the different parts, let's check out various functions of the heart. We all know we need oxygen to survive, but have you ever thought how this oxygen is supplied to different parts of the body? Well, this work is done with the help of heart. Heart plays a very important role in the supply of oxygenated blood to different parts of the body. Deoxygenated blood is collected from various parts of the body and is transferred to the heart. The blood enters the heart through the pulmonary valve and enters the right atrium, then it goes to the right ventricle through the tricuspid valve. From here the blood then goes to the lungs for oxygenation. Oxygenated blood is then brought back to the heart with the help of pulmonary veins and enters the left atrium. The blood then goes to the left ventricle through the bicuspid valve and then transferred to the aorta through the aortic valve for further circulation of blood to different parts of the body.

The heart blood flow diagram (flowchart) given below will help you to understand the pathway of blood through the heart. The blue colour symbolizes impure or deoxygenated blood and red colour denotes pure or oxygenated blood.