2. 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?

3. 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. 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.

4. 5 main blood vessels Arteries - Arterioles Capillaries Venules - Veins Carry blood away from the heart Where gas exchange takes place Carry blood back to the heart

5. Artery Arteriole Venule Vein Capillary

6. Arteries & Arterioles Arteries are large blood vessels, that carry blood away from the heart. Carry Oxygenated blood – Apart from the pulmonary artery, which carries deoxygenated blood to the lungs to get Oxygen Carry Oxygenated blood – Apart from the pulmonary artery, which carries deoxygenated blood to the lungs to get Oxygen 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 peristalsis, and is how smooth muscle contracts 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 peristalsis, and is how smooth muscle contracts

7. 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 Aorta - Main artery leaving the heart It soon splits into smaller vessels – Arterioles – Arterioles deliver the blood to the capillaries

8. 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 - In the capillaries, the blood unloads the Oxygen and picks up carbon dioxide and lactic acid (the waste products of metabolism) Smallest blood vessels – Found in all cells of the body Just one cell thick

9. Veins & Venules Large 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 The blood flows from the capillaries to the venules and then the veins and back to the heart

10. 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 Prevents 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. Deoxygenated blood – Apart from pulmonary vein which carries oxygenated blood from the lungs back to the heart.

11. Task… -Complete the table below ARTERIESVEINSCAPILLARIES FUNCTION TYPE OF BLOOD BLOOD PRESSURE WALL THICKNESS VALVES? LUMEN

12. Blood 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. - 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 Made up of 4 components: -Red blood cells -White blood cells -Platelets -Plasma Plasma Plasma: straw coloured liquid that all solids are carried within.

13. Blood Every cell in your body gets it’s nutrients from your blood. You have 5 litres / 8-9 pints of blood in your body. This makes up 7-8% of your total body weight. In children – most of the bones produce blood In adults – vertebrae, sternum, ribs, pelvis, humerus & femur

14. Red Blood Cells Red blood cells make up 99% of the all the blood cells in the body Red blood cells ‘live’ for 120 days Red blood cells make up 99% of the all the blood cells in the body Red blood cells ‘live’ for 120 days They are RED in colour because they contain HAEMOGLOBIN which attracts & carries OXYGEN Making RED blood cells sole purpose to transport OXYGEN!

15. They are colourless and transparent and fewer in number to red blood cells (1:700) These ‘live’ for 3-4 days 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… fighting potential infection.

16. 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

17. Functions of the blood Blood has three main functions: 1 - Transport of Oxygen & carbon dioxide, nutrients, hormones and waste 2 - Regulation of water in the body and body temperature 3 - Protection against infection and blood loss.

18. Functions of the blood: transport The blood transports: – oxygen from the lungs to the body cells – carbon dioxide from the cells to the lungs – nutrients from digestive system to the cells – waste products from the cells, to be excreted – hormones from endocrine glands, to regulate cells – medication from the blood to the cells.

19. Functions of the blood: heat regulation Body heat Blood picks up heat when it passes through the liver and distributes it around the body. Blood vessels will constrict when the body is cold. This retains heat within the core of the body, where the vital organs are. Blood vessels near the skin’s surface will expand when the body is hot. This allows heat to be lost through the skin.

20. Functions of the blood: water regulation Water content of cells The blood will retain more or less water according to the current water content of the cells When the blood passes through the kidneys, if there is too much water content, the kidneys retain the water and it is excreted If there is not enough water, the kidneys pass water back into the blood to be passed to the body’s cells

21. White blood cells – ‘soldiers’ fight invading organisms – Virus, colds – prevent/fight infections Platelets – ‘barriers’ – blood clotting to prevent loss of blood Functions of the blood: Protection