The heart is a hollow muscle that is located between the lungs. The heart's function is to pump blood into different parts of the body.

The heart consists of four parts: two atria and two ventricles. 

The blood travels through the atria into the ventricles. The walls of the ventricles contain strong muscle cells. When these muscle cells contract, the blood is pumped at a great speed into the blood vessels of the body. 

The aorta is the largest blood vessel in our body. Its purpose is to transport blood from the heart into the arteries.

Veins bring blood from the body into the heart's atria. 

The heart is covered with coronary arteries. These arteries transport oxygen and energy to the cells of the heart itself. 

The heart rests briefly between each heartbeat.

The rate at which the heart beats or contracts is called the heart rate. It can be measured by using your hands or a specialized heart rate meter. The heart can pump blood to the body over 100 times per every minute.

The heart pumps blood into the body in four stages:
1. Blood arrives at the atria.
2.–3. Blood moves from the atria to the ventricles.
4. The muscle cells of the ventricle contract, and the blood is pumped into the body.