5. Gas Exchange

Success Criteria

Your learning has been successful if you can do the following:

I can define ‘gas exchange’.
I can explain how parts of the lung system are important in gas exchange.
I can discuss how diffusion causes gas exchange.

Vocabulary

Learn these so you can communicate this concept well.

Capillary: Tiny blood vessel that carries blood close to the alveoli so that oxygen can move in and carbon dioxide can move out.
Red blood cell: Carries oxygen around the body. Found in the blood.
Oxygen: Gas we need for respiration.
Carbon dioxide: Gas we produce from respiration.
Diffusion: Movement of molecules from an area of high concentration to an area of low concentration.
Concentration: Amount of particles in a mixture
Alveoli: Tiny air sacs where gas exchange happens.

Hei Mahi (Do Now)

Do Now in your OneNote/Notebook:

Think back to the previous lesson. On your diagram, write in the following labels:

capillary, bronchus, alveoli, bronchioles

Exit Task

In your Learning Journal:

Re-write this interpreting question so it is asking about the Gas Exchange:

What is the cause?

Then, write an answer for it.

What is gas exchange?

GAS EXCHANGE is the movement of gases across the alveoli and capillary.

This happens because of the process called DIFFUSION - where molecules move from an area of high concentration to an area of low concentration.

The two gases involved in gas exchange in the lungs are:

OXYGEN - moves from high concentration in the alveoli to the blood.
CARBON DIOXIDE - moves from high concentration in the blood to the alveoli.

Diffusion is maximised by the fact that the walls of the alveoli are thin and moist, and that there are so many of them, creating a huge surface area.