1. Sunday, 24 February 2019
What is gas exchange?
All – Aiming for 4: To be able to list the main structures of the gas exchange system, state that gas exchange happens in the alveoli and use data in the form of percentages to describe the differences between the composition of inhaled and exhaled air.
Most – Aiming for 6: to be able to describe the function of the main structures of the gas exchange system, how alveoli are adapted for gas exchange and describe the processes of ventilation and gas exchange.
Some – Aiming for 8: To be able to explain in detail how the adaptations of alveoli result in efficient gas exchange and explain the differences between the composition of inhaled and exhaled air
Explain why the human circulatory system is described as a ‘double circulatory system’. (3 marks)

2. Explain why the human circulatory system is described as a ‘double circulatory system’. (3 marks)
Because it consists of two circuits joined together.
The first one pumps deoxygenated blood to the lungs to take in oxygen and returns oxygenated blood to the heart.
The second one pumps oxygenated blood around all the other organs of the body and returns deoxygenated blood to the heart.

3. Complete the worksheet
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Complete the worksheet

4. Self assess L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Self assess

6. Use this diagram to describe how the air gets from the nose to the alveoli
Label your diagram

7. Flow chart
Nose
Trachea
Bronchi
Bronchioles
Alveoli

8. Exchange of Gases in the Lungs
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Exchange of Gases in the Lungs
The lungs are found in the upper part of the chest called the thorax.
The diaphragm separates the lungs from your digestive organs, this is called the abdomen.

9. Exchange of Gases in the Lungs
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Exchange of Gases in the Lungs
The job of the breathing system is to move air in and out of the lungs.
Breathing air into the lungs= inhalation
Breathing air out of the lungs = exhalation

10. Watch https://www.youtube.com/watch?v=hc1YtXc_84A
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Watch

11. 9B In… out… in… out...
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Stand up and feel your ribs! Can you feel these movements when you breathe in and out?

12. Where does oxygen enter the blood?
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Where does oxygen enter the blood?
Use the information to explain how the diaphragm moves to allow air to enter and leave the lungs.

14. Inhalation and exhalation
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Inhalation and exhalation
Listen out for:
The changes that occur in the lungs during exhalation
The changes that occur in the lungs during inhalation.

15. L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.

17. L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.

19. Where does oxygen enter the blood?

21. blood coming from the lungs
Laws of diffusion
The movement of the oxygen from the blood to the cells also follows the law of diffusion.
It is highly concentrated within the blood.
Meanwhile the concentration is low within the cell.
blood coming from the lungs
body cell
high concentration
low concentration
Therefore the oxygen passes into the body cells.

22. Task Draw a diagram of the alveoli and explain gas exchange.
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Task
Draw a diagram of the alveoli and explain gas exchange.
You should include the following key terms: concentration gradient, oxygen, carbon dioxide, diffusion, blood, alveoli

23. Plenary
If this is the answer what could the question be…? Gas exchange Alveoli Diffusion Inhalation Diaphragm

24. Resources

26. Inhaled air Exhaled air Reason for difference.
Comparison of inspired and expired air.
L4:To describe the structure of the lungs.
L6:To analyse the events that take place during inhalation and exhalation.
L8:To evaluate how diffusion contributes to successful gas exchange.
Gas
Inhaled air
Exhaled air
Reason for difference.
……..%
16%
0.0……% 4%
(100 times more)
78%
…….% 1%
Variable
Always higher