Download this complete,fully solved and updated actual exam for Physics Unit 2 CCEA GCSE

Blood Carries oxygen and nutrients to the body's cells, and waste products away from them. Arteries Carry blood away from the heart.Very thick, elastic walls. Small lumen High blood pressure.No valves.The muscle provide strength and allow the arteries to expand as blood is pulsed through, preventing them from bursting. The elastic fibres recoil and muscles contract returning the wall to its original size and smoothing out the blood Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:00 / 0:15 Full screen Brainpower Read More Veins Return blood to the heart. Relatively thin walls. Large lumen that reduces friction Low blood pressure. Has valves to prevent back-flow of blood. Capillaries Walls are thin (only one cell thick). They are thin enough to be permeable and allow diffusion to take place. They allow for the exchange of materials with tissues Heart a muscular pump that keeps the blood moving to every part of the body How does the heart beat? 1. The heart muscles relax and blood flows into the atria 2. The atria then contract and the valves open to allow blood into the ventricles 3. The vavles close to stop blood from flowing back wards. The ventricles contract forcing blood to leave the heart. At the same time, the atria are relaxing and once again filling with blood The cycle then repeats itself Transport A function of the circulatory system (involves transport of blood cells, oxygen, CO2, glucose and amino acids). Protection A function of the circulatory system (preventing and fighting against disease). Components of blood Red blood cells, white blood cells, platelets and plasma. Red blood cell Carries oxygen around the body. Has no nucleus so more O2 can attach to it. Has a bioconcaved disc shape so it has a larger surface area. Contains haemoglobin (rich in iron) that carries the oxygen white blood cells are the body's disease fighters Phagocytes a type of cell within the body capable of engulfing and absorbing microorganisms in a process called phagocytosis Lobed nucleus Lymphocytes A type of white blood cell that make antibodies to fight off infections Large central nucleus Platelets Tiny fragments of cells. Important in blood clotting and the formation of scabs They convert fibrinogen (a soluble protein) to fibrin (insoluble). The fibrin forms a mesh that traps other blood components forming a scab Plasma Liquid part of the blood. Straw coloured Its main function is to transport blood components, absorbed food molecules e.g. glucose &amino acids, hormones (ADH & insulin) and waste materials such as carbon dioxide and urea. Double circulation Blood will go through the heart twice in one complete circulation of the body. Valves Prevent back-flow of blood from low pressure in veins. Ensures that the heart acts as a unidirectional pump. They are found in both the heart and the veins. They only open one way Oxygenated blood Rich in oxygen. In most arteries as well as the Pulmonary Vein. Deoxygenated blood Little oxygen present. In most veins as well as the Pulmonary Artery. Capillary function Diffusion of O2, CO2, dissolved food and urea takes place between the capillary and body cells. One cell thick and permeable to allow diffusion to take place. O2 and glucose into body cells; CO2 and urea diffuse out. Renal Artery Carries blood rich in urea to the kidney for excretion Renal Vein carries purified blood away from the kidneys to the vena cava Lung blood vessels Pulmonary Artery and Vein Liver blood vessels Hepatic Artery and Vein Hepatic Portal Vein Coronary arteries Supply heart with oxygen and glucose for