© folens 2009 for edexcel 1.2.2 a healthy, active lifestyle and your cardiovascular system blood...
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Blood vessels 1
Blood vessels
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Task 1
Starting and finishing with the right ventricle, put the following in the correct order to describe blood flow around the body:
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• Left ventricle
• Right atrium
• Aorta
• Pulmonary vein
• Pulmonary artery
• Vena cava
• The lungs
• The body
• Left atrium
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Task 1 answers
Right ventricle
• Pulmonary artery
• The lungs
• Pulmonary vein
• Left atrium
• Left ventricle
• Aorta
• The body
• Vena cava
• Right atrium
Right ventricle
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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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:
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Recap of the circulatory system:
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
The blood vessels
There are three main types of blood vessel:
• Arteries
• Veins
• Capillaries
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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An artery:
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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).
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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).
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
A vein:
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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).
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Effects of inactivity
Oxygen is not exchanged as easily between muscles during inactivity due to the cooler blood vessel and blood temperature.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Effects of exercise onblood vessels
When blood in the veins flows close to the working muscles, the ‘skeletal pump’ effect helps move blood around the body.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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.
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© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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Exam questions1. 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
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
Blood vessels 27
What you have learntin this topic:
1. What blood vessels are and what they do
2. Arteries
3. Veins
4. Capillaries
© Folens 2009FOR EDEXCEL 1.2.2 A healthy, active lifestyle and your cardiovascular system
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
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