P5 Assessment To achieve P5 you need to describe: • • • The different structures within the heart (i.e. atria, ventricles and so forth). The different types of blood vessels (such as the arteries) outlining their structure and function, i.e. thick walls and taking blood away from the heart. The role of the circulatory system both at rest and during exercise, i.e. delivery of oxygen to the muscles and removal of waste products. To achieve M2 you need to explain the function of the cardiovascular system: • How does it work? • How is each part of the system designed to meet its function? The Blood Vessels Introduction We have a variety of different vessels within the cardiovascular system to deliver and remove nutrients and waste products. Blood in the arteries is bright red, as it is carrying oxygen. It drops off the oxygen and picks up carbon dioxide as it moves through the capillaries. By the time it reaches the veins and venules it is a much darker blue/red colour. 5 main blood vessels • Arteries Carry blood away from the heart – Arterioles • Capillaries Where gas exchange takes place – Venules • Veins Carry blood back to the heart • Arteries are large blood vessels, that carry blood away from the heart. Arteries & Arterioles •Thick Elastic muscular walls Artery walls contain elastic cartilage and smooth muscle, This allows the arteries walls to contract and relax to send blood to all parts of the body This process is known as perstalsis, and is how smooth muscle contracts •Carry Oxygenated blood –Apart from the pulmonary artery, which carries deoxygenated blood to the lungs to get Oxygen Arteries & Arterioles • Small round lumen • Operate under high pressure • Arteries don’t contain valves, as the blood is moving quickly under high pressure, so there is no chance of backflow. Aorta –Main artery leaving the heart It soon splits into smaller vessels – Arterioles –Arterioles deliver the blood to the capillaries Smallest blood vessels – Found in all cells of the body Just one cell thick • Capillaries Very thin walls – Allows oxygen and other nutrients to diffuse through the cell walls. • Blood flows very slowly through the capillaries so that this can happen – Effectively in the capillaries, the blood unloads the Oxygen and picks up carbon dioxide and lactic acid (the waste products of metabolism) Veins & Venules • The blood feeds from the capillaries back to the venules and then the veins. • Larger oval lumen – Means blood flows at lower speed and pressure. • Thinner and less muscular than arteries – Have some smooth muscle • Contracts to help sent the blood back to the heart Veins & Venules • Carry blood back to the heart – Generally working against gravity • Particularly blood that is going back to the heart from the legs or arms, as it is below the heart. – Valves • To prevent the blood from flowing back once the smooth muscle relaxes. • Prevents pooling, particularly in the legs Deoxygenated blood – Apart from pulmonary vein which carries oxygenated blood from the lungs back to the heart. Task… You are going to outline the function and characteristics of each of the 6 types of Blood Vessels that serve the circulatory system… Including: - Physical characteristics that classify each blood vessel. - What their function is within the CIRCULATORY system? - What do they transport? Blood It is the medium in which all the cells are carried to transport nutrients and Oxygen (O2) to the cells of the body. It carries: - Oxygen, Glucose, Proteins, Fats, Vitamins, Hormones, Enzymes, Platelets, Carbon Dioxide and Electrolytes. Made up of 4 components: - Red blood cells White blood cells Platelets Plasma Plasma: straw coloured liquid that all solids are carried within. Red Blood Cells Red blood cells make up 99% of the population of the blood cells in the body They are RED in colour due to the presence of a protein called HAEMOGLOBIN and absolutely loves Oxygen (massive attraction!) Making RED blood cells soul purpose to transport OXYGEN! Cells They are colourless and transparent and fewer in number to red blood cells (1:700) The role of White blood cells is to fight infection as they are part of the immune system. They destroy bacteria and other dangerous organisms… thus fighting potential infection. Platelets They become sticky when in contact with air to form the initial stage of repair to the damaged tissue… They act by stopping blood loss through clotting Yet platelets need a substance called x-Factor 8 to enable them to become active and do their job/clot.