4. What structures make up the human circulatory system?

Knowledge

The human circulatory system is made up of 3 parts that work together to move oxygen, glucose, nutrients and other chemicals to where they are needed. These 3 parts are: 1) the heart, 2) blood vessels, 3) blood.

The heart is a 4-chambered pump that pushes blood around the body. The heart has 2 sides: left and right. The left side is larger than the right and has thicker muscle making up the walls. This is because it has to pump blood around the whole body, whereas the right side only needs to pump blood to the lungs which are only a short distance away.

In each side blood moves from the top chamber (atrium) to the bottom chamber (ventricle) through a valve. No blood mixes between the left and the right sides of the heart as there is a thick wall separating the two, called the septum.

There are 3 types of blood vessels: the arteries (that move blood away from the heart), the veins (that move blood towards the heart) and the capillaries (very thin tubes that connect the arteries to the veins). The capillaries travel close by every cell in the body so oxygen, glucose and nutrients can be dropped off to be used by the cells.

Blood is the third part that makes up the circulatory system. Blood is made of a liquid called plasma and blood cells. There are 3 types of blood cells: red blood cells that carry around oxygen, white blood cells that prevent disease and platelets that helps the blood to clot and stop the bleeding from a cut.