The Circulatory system

The circulatory system is in fact known as a double circulatory system, this is because it is made up of two interweaving loops and blood passes through the heart twice. The heart is at the centre of this system. The heart is divided into two halves, the right and the left. Blood from these two halves never mix.

The animation below shows how the human circulatory system works:

The Circulatory System


The first loop is known as the Pulmonary Circulation. Blood is pumped out of the right side of the heart and travels to the lungs. In the lungs blood picks up oxygen and becomes oxygenated at the same time carbon dioxide is removed. The oxygenated blood then travels back to the left side of the heart.

circulatory system

The second loop is known as the Systemic Circulation. Here the oxygenated blood is pumped by the left side of the heart to the rest of the body. It delivers oxygen to the body’s cells and becomes deoxygenated. It also picks up Carbon dioxide and other waste products. This deoxygenated blood then makes it way back to the right side of the heart where the cycle is repeated.