1. The Body in Action
The Need for Energy
Mr G Davidson

2. Using Energy We use up energy as we go about our everyday lives.
All foods contain some energy, however different foods contain different amounts.
1g carbohydrate kJ
1g protein kJ
1g fats kJ
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3. Using Energy
The amount of energy needed by the body changes during life.
It depends on the person’s age, sex, job and lifestyle. E.g.
Infant kJ
5 yr old kJ
15 yr old boy kJ
15 yr old girl kJ
Active woman kJ
Active man kJ
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4. Carbon dioxide in Air
We need oxygen to release the energy from our food.
A waste product, CO2 is produced during this process.
We obtain O2 and get rid of CO2 by breathing.
The air we breathe in is called INHALED AIR.
The air we breathe out is called EXHALED AIR.
The 2 are VERY different.
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5. Carbon Dioxide in Air Exhaled air contains more CO2 than inhaled air.
Indicator
Breathe gently
Air in
Air out A B
Exhaled air contains more CO2 than inhaled air.
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6. Oxygen Content
To compare the oxygen content of inhaled and exhaled air we can compare their ability to support burning.
To obtain a sample of exhaled air.
Breathe out
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7. Oxygen Content
Exhaled air
Inhaled air
The candle in the exhaled air goes out first because there is less oxygen in this jar.
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8. Exhaled air is also warmer and contains more water than inhaled air
Oxygen Content
Oxygen
Carbon Dioxide
Nitrogen
Inhaled air
20.96%
0.03%
79%
Exhaled air
16.4%
4.1%
Exhaled air is also warmer and contains more water than inhaled air
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9. Human Thorax Our lungs allow us to take in oxygen and give out CO2.
Our lungs and heart are in the chest which is a sealed unit called the thorax.
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10. Human Thorax Bronchioles Blood capillaries Nasal cavity Mouth
Epiglottis
Trachea
Bronchi
Alveoli
Rib
Oesophagus
Intercostal muscle
Lungs
Diaphragm
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11. Lungs These are spongy organs which have a very large surface area.
The bronchioles end in tiny air sacs called alveoli which are lined with moisture.
Oxygen dissolves in this moisture and diffuses into the blood while CO2 diffuses in the opposite direction.
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12. Lungs
The lungs are well designed for gas exchange and the following features ensure this.
Large surface area.
Good blood supply.
Moist lining.
Thin walls.
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13. Alveolus
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14. Breathing
Movements of the thorax wall help us to take in and give out air.
The diaphragm and intercostal muscles between the ribs are used to help us breathe.
As we breathe, our thorax changes in size.
Our lungs expand and contract.
Breathing movements help to change the volume and pressure of the thorax.
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15. Air Passages
Air contains dust and germs which can damage the lungs and therefore have to be removed.
The air we breathe in is cleaned by cells lining the air tubes.
These cells have small hairs (cilia) which move in waves towards the mouth.
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16. Air Passages
A slippery liquid called mucus, which traps the dirt and germs, is made by the cells.
The mucus acts like a conveyor belt which is moved by the beating cilia.
In this way, dirt and germs are carried up to the mouth where they are swallowed.
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17. Air Passages
Cilia
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18. Heart
Oxygen and food are carried to all body cells by blood in the blood vessels.
The heart pumps the blood around the body.
Heart animation
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19. Heart
Bicuspid valve
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20. Heart Pulmonary artery Aorta Vena cava Left atrium Pulmonary vein
Right atrium
Bicuspid valve
Tricuspid valve
Left ventricle
Right ventricle
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21. Heart
The atria have very thin walls while the ventricles have thicker walls.
The wall of the left ventricle is much thicker than the right due to a higher pressure required to pump blood all around the body.
The heart has valves to stop blood flowing in the wrong direction.
Circulation animation
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22. Arteries, Veins and Capillaries
Blood is carried to all body cells in vessels.
Blood leaves the heart in arteries, is carried through organs and tissues in tiny vessels called capillaries and returns to the heart in veins.
Arteries have thick muscular walls and no valves.
Veins have thin walls and valves all along their length.
Capillaries are only one cell thick to allow diffusion.
If all the capillaries in your body were laid end to end, they would go twice round the world.
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23. Red Blood Cells
Blood is made up of cells floating in a liquid called plasma.
Red blood cells are very small and can only be seen with the aid of a high power lens on a microscope.
Red blood cells contain a pigment called HAEMOGLOBIN which is used to carry oxygen around the body.
When oxygen joins it, it forms OXYHAEMOGLOBIN.
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24. Blood
Blood contains other kinds of materials e.g. white blood cells and platelets.
White blood cells fight invading bacteria and destroy them by engulfing them.
Platelets help the blood to clot at a cut.
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25. Blood Cells
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26. Blood Plasma Blood cells float in a liquid called PLASMA.
It also carries substances round the body like CO2, products of digestion, waste materials like urea, etc….
The body cells give up their CO2 to the blood and receive oxygen from the blood.
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