ks3 science lesson

1. L.O: How are gases exchanged in the lungs?
Starter: which gases are exchanged and why?
Extension: name these parts of the respiratory system that are mixed up
( look at the diagram from last lesson):
ronchubs soulvale archtea nolbrioche trencosisalt
Gas exchange
1 October, 2019

2. Starter answer
oxygen – reactant for respiration
carbon dioxide – toxic product of respiration
• Extension answer:
•bronchus alveolus Trachea bronchioles intercostals
1 October, 2019
Mark in green pen

3. Would you donate your body to science?

4. • https://www.activeteachonline.com/product/view/id/335/page/40/
mode/dps?modal=/player/animation/id/390816

5. The model lung
Trachea
Bronchus
Lung
diaphragm
The diaphragm moves _______ when
We breathe in. This makes the space
inside the chest _____which makes the
pressure _____.
The diaphragm moves _______ when
We breathe out. This makes the space
inside the chest _____which makes the
pressure _____.

6. Inhalation and exhalation

7. Collapsed lung
• https://www.activeteachonline.com/product/view/id/335/page/40/
mode/dps?modal=/player/video/id/389223

8. Cilia function
• https://www.activeteachonline.com/product/view/id/335/page/40/
mode/dps?modal=/player/video/id/389222

9. Ventilation
• Movement of air into and out of the lungs is
called ventilation
How many times do you inhale in a minute? This
is your breathing rate.
The typical respiratory rate for a healthy adult at rest is 12–20 breaths per minute.
Breathing is when muscles
change the size of the lungs

10. Gas exchange
The carbon dioxide that leaves your blood is
excreted when you breathe out

11. • The alveoli have a very large surface area,
speeding up diffusion
• The alveoli are one cell thick, also speeding
up diffusion
• The capillaries also have very thin walls
Adaptations for gas
exchange

12. Adaptations for gas exchange
• The alveoli have a very large surface area,
speeding up diffusion
• The alveoli are one cell thick, also speeding
up diffusion
• The capillaries also have very thin walls

13. Pulse oximeters

14. Student
name
Oxygen saturation
(%)
Pulse (BPM )
jake 97 87
Irfan 97 94
Ruby r 97 77
Ruby c 97 67
courtney 97 95
salman 91 78
maison 97 94

15. homework
• Draw a bar chart of the results
• Are all the results normal ?( 95-100 % oxygen saturation and 70-100
beats per minute)
• Why is it a problem if the oxygen sats are too low?

16. • Bronze:
(fnd/dev)
• Silver:
(sec)
• Gold:
(exc)
Learning Outcomes: PROGRESS CHECK
1 October,
2019
What is diffusion?
Explain the process of gas exchange in the lung
Explain how changes in pressure cause inhalation and exhalation

17. • Bronze:
• (fnd/dev)
• Silver:
• (sec)
• Gold:
• (exc)
Learning Outcomes: PROGRESS CHECK
1 October,
2019
Movement of particles from high concentration to low concentration
Oxygen diffuses from the alveoli into the capillaries and into red blood cells.
Carbon dioxide diffuses in the opposite direction
When the diaphragm moves down, the volume inside the chest cavity
expands, this lowers pressure inside the chest cavity and air moves from high
pressure outside to low pressure inside. When the diaphragm moves up, the
opposite effect happens.
Mark in green pen