Transporting Materials

Materials are moved around the body in transport systems, in humans this is a circulatory system which consists of blood vessels, the blood and your heart. The heart is two pumps held together, the right pump forces blood into the heart, this blood loses carbon dioxide and gains oxygen, this blood is deoxygenated. Once it has gained oxygen, the oxygenated blood is pumped around the body by the left pump. Blood comes into the atria in the heart from the veins, it is then transported to the ventricles where it gains oxygen and loses carbon dioxide. The blood leaves the heart through the arteries. When both sides of the heart are functional, it is called a double circulation. Valves prevent blood from flowing in the wrong direction. Arteries carry blood away from the heart and have thick walls containing muscle and elastic tissue, this allows them to adapt to the blood flow. Veins have thinner walls and often have valves along their length to prevent backflow of blood; capillaries have walls which are much more narrow, only a single cell thick, and carry blood through the organs and allow the exchange of substances with living cells in the body.

If the blood vessels become blocked or narrowed with fatty deposits, then blood doesn’t flow efficiently meaning that cells become deprived of nutrients and oxygen. Stents can be inserted to widen a vessel, this is usually done by inserting a deflated ‘balloon’ with a stent around it into the vessel, inflating the balloon so the stent expands to the size of the vessel, and then…