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The heart

What you will learn about in this topic:

1. The heart

2. The heart as a double pump

3. The circulatory and pulmonary systems

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The heart 3

Learning objectives

By the end of this presentation you should be able to:

• Understand how the heart and the circulatory and plumonary systems work

• Describe the heart as a double pump

• Explain why systems are important to athletes

The circulatory system

The circulatory system involves the heart, blood vessels and blood itself. These are the three essential components the body needs to survive.

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The circulatory system is made up of two separate circuits that blood travels through: the pulmonary circuit and the systemic circuit.

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This is a double circulatory system and blood passes through the heart twice.

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The functions of the circulatory system

Oxygen and nutrients are transported to parts of the body, while waste or toxic products are removed.

The balance of nutrients keeps the body functioning properly.

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The body relies on these actions to stay alive.

The circulatory system controls body temperature. The body is affected by changes to temperature, so keeping it in an acceptable range keeps the body functioning properly.

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The circulatory system also helps protect the body; antibodies in the blood fight disease and platelets help to clot the blood at the source of a cut to prevent other germs entering the body.

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Task 1

Create prompt cards by writing down the main functions of the circulatory system on A6 size cards.

Make sure they are neat and concise. They will help you to revise later on!

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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

On heart diagrams, red arrows usually denote the arteries, showing oxygenated blood.

Blue arrows usually denote the veins, showing deoxygenated blood.

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Task 2

1. Draw a copy of the heart diagram and label it.

2. Show the flow of blood through the heart on your diagram. Use colour (red and blue) to show where the blood is oxygenated and deoxygenated.

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The heart as a pump

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The heart acts as a pump in the double circulatory system.

When the heart beats (contracts) it is called systole. This action forces blood through the arteries around the body.

When the heart relaxes it fills with blood returning from the veins. This is called the diastole or diastolic phase.

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The pulmonary circuit carries deoxygenated blood from the heart, from the right ventricle, to the lungs, via the pulmonary artery; the blood is then oxygenated (carbon dioxide is removed from the blood in the lungs).

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The oxygenated blood is then taken from the lungs, via the pulmonary vein, and taken to the left atrium of the heart (oxygen is taken up by the haemoglobin in red blood cells).

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The systemic circuit carries oxygenated blood from the heart, pumped from the left atrium to the left ventricle into the aorta, to the rest of the body so it can use the oxygen.

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Deoxygenated blood is then taken back from the body to the right atrium of the heart via the vena cava.

The cycle then starts over again.

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The heart

The heart has four chambers. The two atria collect blood and the two ventricles pump the blood out of the heart.

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Deoxygenated blood Oxygenated blood

The right side of the body pumps deoxygenated blood (blood with no oxygen in it) to the lungs.

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Oxygenated blood

The left side pumps oxygenated blood (blood with more oxygen in it) from the lungs to the rest of the body.

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Deoxygenated blood

The septum divides the left and right sides of the heart so that oxygenated and deoxygenated blood do not mix.

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Septum

The left ventricle wall is thicker than the right side. It is more developed as it pumps blood further around the body.

Left ventricle

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Sets of valves are positioned in the heart to stop the backflow of blood.

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Semi-lunar valve

Task 3

Draw a diagram in your work book showing the pulmonary and systemic systems.

Clearly label your diagram.

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Task 4

As a class, discuss why you think the circulatory system is important to sportspeople.

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Exam questions1. Which of the following best describes the pulmonary circuit?

A. Heart – pulmonary arteries – lungs –pulmonary vein – heart

B. Heart – aorta – lungs – pulmonary vein – heart

C. Heart – pulmonary arteries – capillaries – lungs – pulmonary vein – heart

D. Heart – pulmonary arteries – lungs – vena cava – heart

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What you have learntin this topic:

1. The heart

2. The heart as a double pump

3. The circulatory and pulmonary systems

4. Functions of the circulatory system

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Learning objectives

You should now be able to:

• Understand how the heart and the circulatory and pulmonary systems work

• Describe the heart as a double pump

• Explain why systems are important to athletes