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3. Energy release
When something burns, heat and light energy is released.
This process will produce energy if there are 2 main ingredients.
FUEL + OXYGEN
combustion
+ Water +
Carbon
dioxide
If these two and heat are all present then the fuel and oxygen will react. This reaction is called COMBUSTION.

4. The Heart
The heart is made of very special muscle, CARDIAC muscle. It must keep beating all the time for the rest of a persons life! If you tried to do the same action repeatedly (like the heart) your muscles would get tired and, after a while, they would stop working.
For example if you clench and unclench your hand continuously, it will get tired, and may even start to cramp.

5. The blood system
This is the system which carries the dissolved food and oxygen around the body. This includes the heart and the lungs.

6. Blood cells provide oxygen and the plasma in the blood carries dissolved food to ALL the cells in the body.

7. Inhalation
(When we breathe in we inhale)

8. What type of fuel is required by the body?
The body changes food into a form which can be carried around the body. This substance is called GLUCOSE.
Glucose contains energy.
When glucose reacts with oxygen a LOT of energy is produced. Some of this energy is released as heat while the rest is used by the cells.
The cells do NOT catch fire.

9. We can now write out the full equation for RESPIRATION.
What is respiration?
RESPIRATION is the process which releases energy from food. This is NOT the same as breathing.
We can now write out the full equation for RESPIRATION.
FOOD (GLUCOSE)
OXYGEN +
from digestive system
from breathing system
WATER
CARBON DIOXIDE +
ENERGY
USEFUL!
waste product exhaled
Combustion is different because it is NOT a controlled reaction. Respiration IS a controlled reaction which SLOWLY releases energy from food in the CELLS.

10. How does oxygen get into our body?
The body separates the process of breathing in and breathing out.
Breathing in is one process and is known as inhalation . When we inhale we breathe in air, taking oxygen with it into our lungs.
Breathing out is a separate process and is known as exhalation . When we exhale we breathe out the contents of our lungs, pushing out waste gases like carbon dioxide

11. Exhalation
(When we breathe out we exhale)

12. The Alveoli
Oxygen makes its way into thousands of special air sacs collectively called the ALVEOLI.
The outside of the alveoli is covered with tiny blood vessels.

13. The Alveolus One of these alveoli is called the ALVEOLUS.
This is where the oxygen is transferred into the blood and carbon dioxide moves out of the blood.
If all these alveoli flattened and spread out onto the floor, they would cover an area the size of a tennis court!

14. Different types of activity
What happens to the man’s pulse rate when running?
The pulse is faster:
Blood is pumped around the body faster.
Oxygen and glucose reach muscle cells more quickly.
Energy is used up faster.
While sleeping
Blood is pumped around the body more slowly.
Oxygen and glucose reach body cells more slowly.
Energy is used up at a slower rate.

15. Anaerobic Respiration
When the body can supply the cells with the oxygen and food that they need, We say it is performing AEROBIC respiration. The equation for this is:
Glucose + oxygen Carbon dioxide + water + ENERGY
Anaerobic Respiration
When the body CANNOT supply the cells with the oxygen and food that they need, then the body must perform anaerobic respiration. The release of energy WITHOUT oxygen:
Glucose Lactic acid + a little energy

16. Not enough oxygen
When anaerobic respiration takes place, the lactic acid soaks the muscle cells and prevents the muscle cell from doing its job. This causes fatigue and/or cramp.
After the activity has been completed people pant and breathe heavily. This happens because oxygen is required to get rid of the build up of lactic acid.

17. Comparing inhaled and exhaled air
What are the big differences between inhaled and exhaled air?
How could you test for these?
Inhaled Air
Nitrogen (78%)
Oxygen (20.71%)
Carbon Dioxide (0.1%)
Other
Exhaled Air
Nitrogen (75.5%)
Oxygen (14.6%)
Carbon Dioxide (4%)
Other
There is another difference……
…… water vapour.