1. What you will learn about in this topic: 1.What blood vessels are and what they do 2.Arteries 3.Veins 4.Capillaries Blood vessels 2

2. Blood vessels 3 Learning objectives By the end of this presentation you should be able to: Understand the different types of blood vessel Describe how blood vessels work Explain the effects of exercise and inactivity on blood vessels

3. Task 1 Starting and finishing with the right ventricle, put the following in the correct order to describe blood flow around the body: Blood vessels 4 Left ventricle Right atrium Aorta Pulmonary vein Pulmonary artery Vena cava The lungs The body Left atrium

4. Task 1 answers Right ventricle Pulmonary artery The lungs Pulmonary vein Left atrium Left ventricle Aorta The body Vena cava Right atrium Right ventricle Blood vessels 5

5. Blood vessels 6 Superior vena cava Right atrium Tricuspid value Septum Right ventricle Aorta Pulmonary artery Pulmonary veins Left atrium Semi-lunar valve Mitral value Left ventricle Recap of the heart:

6. Recap of the circulatory system: Blood vessels 7

7. The blood vessels There are three main types of blood vessel: Arteries Veins Capillaries Blood vessels 8

8. Arteries Arteries carry oxygenated blood from the heart to the rest of the body (apart from the pulmonary artery where deoxygenated blood goes to the lungs). The longest artery in the body is the aorta. Blood vessels 9

9. Blood vessels 10 An artery:

10. Smaller arteries branch off the aorta, they then divide into smaller arterioles and then into even smaller capillaries. The outer layer of an artery is tough and fibrous, the inner liner is elastic. The blood stretches the walls, the walls contract and force the blood along. Blood vessels 11

11. Arteries have small passageways for blood (internal lumen – the open space inside a blood vessel that blood travels through). Blood in the arteries is bright red due to the presence of oxygen (apart from in the pulmonary artery). Blood vessels 12

12. Veins Veins carry deoxygenated blood from the body to the lungs (apart from the pulmonary veins where oxygenated blood travels from the lungs to the heart). Blood vessels 13

13. A vein: Blood vessels 14

14. Veins have a large lumen and the blood flows slower, at a lower pressure. Veins have much thinner walls than arteries. Blood in the veins is dark red due to the presence of carbon dioxide and the lack of oxygen (apart from in the pulmonary veins). Blood vessels 15

15. Veins contain valves to stop the blood from flowing backwards and pooling, avoiding problems like varicose veins. Veins eventually split into venules and then into capillaries. Blood vessels 16

16. Capillaries Capillaries are microscopic blood vessels, much thinner than a human hair; most let only a single blood cell through at a time. They are found in the muscles and lungs. Blood vessels 17

17. Blood vessels 18

18. Gas exchange takes place through the walls of the capillaries. Oxygen and nutrients are passed into tissues and carbon dioxide and waste products pass from the tissues into the blood. Blood vessels 19

19. At the end of the capillaries blood flows back into veins and returns to the heart via the vena cava at a very low pressure. There are over 100,000 km of capillaries in the body. Blood vessels 20

20. Task 2 List as many differences and similarities between arteries, veins and capillaries as you can. For example, the arteries carry oxygenated blood as do the veins whereas the capillaries carry both oxygenated and deoxygenated blood. Blood vessels 21

21. Effects of inactivity Oxygen is not exchanged as easily between muscles during inactivity due to the cooler blood vessel and blood temperature. Blood vessels 22

22. Inactivity can lead to storing energy around the body as fat. Storing fat, like cholesterol, in the blood vessels reduces the space for the blood to flow through them, which raises blood pressure. This can put great stress on the heart and blood vessels and can lead to problems such as a heart attack. Blood vessels 23

23. Effects of exercise on blood vessels When blood in the veins flows close to the working muscles, the ‘skeletal pump’ effect helps move blood around the body. Blood vessels 24

24. The blood vessels increase in size to allow more blood to flow to the working muscles. An increase in blood temperature helps blood to flow better. Oxygen is exchanged with the muscles more easily when blood is warm. Blood vessels 25

25. Blood vessels 26 Exam questions 1. Which of the following best describes a vein? A.Works at lower pressure than other blood vessels, has semi-permeable walls B.Has valves, works under high pressure, transports oxygenated blood C.Walls are thin, has valves, works at a low pressure, transports deoxygenated blood D.Transports deoxygenated blood, divides into arterioles, walls are one cell thick

26. Blood vessels 27 What you have learnt in this topic: 1.What blood vessels are and what they do 2.Arteries 3.Veins 4.Capillaries

27. Blood vessels 28 Learning objectives You should now be able to: Understand the different types of blood vessel Describe how blood vessels work Explain the effects of exercise and inactivity on blood vessels