Understanding the cardiovascular system

There are three main parts of the cardiovascular system, this includes the heart, blood vessels and the blood that flows throughout our whole body.

The heart

Your heart is located in the middle of the chest and is approximately the same size as your clenched hand. The heart is divided into two sides, each side consists of an atrium and ventricle, which are two connected chambered. The right side of the heart is responsible for pumping deoxygenated blood to the heart. The left side of the heart is responsible for pumping oxygenated blood around the body.

  • The atria are where the blood collects once it has entered the heart

  • The ventricle pumps blood out of the heart to the lungs and around the whole body

  • The septum divides the right and left-hand side of the heart

  • The tricuspid and bicuspid valve are located between the atrium and ventricle and open when there is a build-up of pressure.

  • The semilunar valves help to prevent any of the blood flowing back into the heart

  • The blood vessels are responsible for taking blood in and out of the heart. The aorta is the largest artery in the body and has the job of caring oxygenated blood away from the heart to the body. The vena cava is the largest vein in the body and has the job of varying blood to the heart.

Blood vessels

There are three types of blood vessels, this includes the arteries, capillaries and veins. They each have different qualities that help them to do their job effectively.

  • Arteries- they carry blood away from the heart, which is usually oxygenated, however, the pulmonary artery is the only artery to carry deoxygenated blood. Arteries have a thick, muscular wall, which allows them to work under high pressures.

  • Capillaries- they are responsible for getting nutrients from the blood into the relevant cells. The walls are made up of semi-permeable membranes which allow the nutrients to pass in and out of the blood.

  • Veins- they carry blood to the heart, which is usually deoxygenated however, the pulmonary vein is the only vein to carry oxygenated blood. Veins contain small valves which prevent any blood from flowing backwards.


The primary function of blood is to transport oxygen and nutrients around the body. There are four different components in the blood.

  1. White blood cells- their job is to fight infections

  2. Platelets- form scabs and clots during injuries

  3. Plasma- the liquid part of the blood

  4. Red blood cells- these transport oxygen. They are disc-like shaped cells; this gives them a big surface area, allowing them to carry as much oxygen as possible.