1. Dawn Genner

2. Red cells: Most common blood cell, making around 45% of theblood. Doughnut-shaped. Do not have a nucleus. Contain haemoglobin (which is why theyre red) Live for approximately 120 days. Carry oxygenated blood from lungs to cells thatneed it. 3. White cells Search for bacteria Carry antibodies Antibodies = our bodies defences against virusesand bacteria. Part of: our immune system. 4. Platelets Fragments of cells Used to help clot (coagulate) the blood. Platelets live for an average of 10 days. 5. Plasma Is a pale yellow colour Is 90% water Plasma allows other blood cells to move around. 6. It is made in the centre of our bones = in our bonemarrow. 7. There are three types of blood vessel:Arteries Carry blood away from the heart(always oxygenated apart from the pulmonaryartery which goes to the lungs) Have thick muscular walls Have small passageways for blood(internal lumen) Contain blood under high pressure 8. Veins Carry blood to the heart (always de-oxygenatedapart from the pulmonary vein which goes fromthe lungs to the heart) Have thin walls Have larger internal lumen Contain blood under low pressure Have valves to prevent blood flowing backwards 9. Capillaries Found in the muscles and lungs Microscopic one cell thick Very low blood pressure Where gas exchange takes place. Oxygen passesthrough the capillary wall and into the tissues,carbon dioxide passes from the tissues into theblood 10. When an infective cell is detected, white bloodcells will send out a message to another type ofcell: t-helper cells. This also triggers your immune system.Your bodyreleases millions of antibodies to fight off theenemy cells. The antibody cells join themselves to the bacterialcell in an attempt to overpower it. 11. As this process continues, the number of infectiouscells will decrease and the body can stop the battle. Another kind ofT cell, theT-suppressor cell (orT8 cell),will send out messages to the other cells and "de-activate" them. Without theT-suppressor cells, the body wouldcontinue trying to fight off a disease that no longerexists (and eventually would end up fighting its owncells). 12. Bruising is caused by blood vessels becomingdamaged, which causes bleeding into the skin. 13. Control of body temperature Keeping out infection Its a waterproof barrier Protects delicate tissues underneath Mends itself when damaged 14. Plants: structure and cells What can you remember?!?!?!