The Circulatory System

• to pump blood around the body • blood will transport nutrients and oxygen to cells and take away waste e.g. CO2

• Transport oxygen to the cells for respiration • transport food to the cells • transport waste materials away from cells e.g.CO2 • help fight infections - white blood cells • help regulate body temperature at 37degrees Celsius

• carry’s oxygen from our lungs to cells • haemoglobin gives blood its colour

Defend against infection. They have a nucleus unlike red blood cells

• clots blood • prevents blood loss + prevents entry of microorganisms

• transport • liquid part of the blood

• thick walls - muscle wall • smaller lumen • deep in the body-difficult to damage • always carry’s blood away from the heart • blood in arteries is under pressure from the pumping action of the heart • carries oxygenated blood

• thin walls - muscle walls • big lumen • closer to the surface of the body - easier to damage • always carry’s blood towards the heart • blood in veins is not under pressure and needs valves to prevent the blood flowing backwards • Carries deoxygenated blood

• only one cell thick • very thin walls to allow substances to pass into cels from the blood, e.g. oxygen.food and water • waste and carbon dioxide pass through capillaries from the cells to the blood

Pulmonary artery - carries blood from the right ventricle to the lungs Vena cava - carries blood from around the body to the heart Right atrium - receives deoxygenated blood from the vena cava Right ventricle - receives blood from the right atrium , pumps blood into the pulmonary artery Septum - wall separating both sides of the heart Aorta - carries blood from the heart to send it around the body Pulmonary vein - carries blood back from the lungs to the left atrium Left atrium - receives oxygenated blood from the pulmonary vein Valve - valves prevent the blood flowing backwards Left ventricle - receives blood from the left atrium , pumps blood into the aorta • arteries carry oxygenated blood except for the pulmonary artery • all veins carry deoxygenated blood except for the pulmonary vein • the wall of the left ventricle is thicker because it has to pump blood all around the body Left Oxygenated Right Deoxygenated

• exercise requires energy • we get energy from respiration • respiration requires oxygen • blood delivers oxygen to cells so it needs to move faster in order to deliver enough oxygen from the increased level of repiration caused by exercise