The human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The heart is a muscle whose working mechanism is made possible by the many parts that operate together. The organ is divided into several chambers that take in and distribute oxygen-poor or oxygen-rich blood. These chambers are accompanied by veins and arteries that facilitate the same function. With all of its parts working together towards the same goal, the heart successfully pumps blood with ease.

The heart muscle contracts in two stages to squeeze blood out of the heat, This is known as systole.

• In the first stage, the upper chambers (atria) contract at the same time, pushing blood down into the lower chambers(ventricles).
• Blood is pumped from the right atrium down into the right ventricle and from the left atrium down into the left ventricle.
• In the second stage, the lower chambers contract to push this blood out of the heart to either the body via your main artery (aorta) or to the lungs to pick up oxygen.

The heart then relaxes- known as diastole. Blood fills up the heart again, and the whole process, which takes a fraction of a second, is repeated.
The different sides of the heart have different functions:

• On the right side, the upper chamber fills with oxygen-depleted blood from your body and pushes it via the lower chamber and the pulmonary artery back to the lungs. Here blood picks up oxygen and releases carbon dioxide.
• On the left side, the upper chamber fills with oxygen-rich blood from the lungs. This is pumped via the lower chamber into the aorta and out to the body to provide cells with the crucial oxygen they need.