1. Blood vessels 1
Blood vessels

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

3. 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

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

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

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

7. Recap of the circulatory system:
Blood vessels 7
Recap of the circulatory system:

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

9. Blood vessels 9
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.

10. Blood vessels 10
An artery:

11. Blood vessels 11
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.

12. Blood vessels 12
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).

13. Blood vessels 13
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).

14. Blood vessels 14
A vein:

15. Blood vessels 15
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).

16. Veins eventually split into venules and then into capillaries.
Blood vessels 16
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.

17. Blood vessels 17
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.

18. Blood vessels 18

19. Blood vessels 19
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.

20. There are over 100,000 km of capillaries in the body.
Blood vessels 20
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.

21. Blood vessels 21
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.
Teacher’s notes
Similarities – they both carry blood.
Differences – arteries are less elastic than veins. The walls of the arteries are thick and the capillaries are thin, sometimes only one cell thick. Arteries rely on pressure from the heart’s pump action to pump blood, veins use gravity and valves to move the blood through them.

22. Blood vessels 22
Effects of inactivity
Oxygen is not exchanged as easily between muscles during inactivity due to the cooler blood vessel and blood temperature.
Source: New England journal of Medicine 22

23. Blood vessels 23
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.

24. 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. 24

25. An increase in blood temperature helps blood to flow better.
Blood vessels 25
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.

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

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

28. Learning objectives You should now be able to:
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