3. Structure & Function of the
Human Lung System

Success Criteria

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

I can label a diagram of the human lung system.
I can describe each of the structures making up the human lung system.
I can explain the function of each of the structures in the human lung system.

Vocabulary

Learn these so you can communicate this concept well.

Larynx (voice box): Helps to create different sounds when we speak.
Trachea (windpipe): Carries air from the nose down to the bronchi.
Cartilage rings: Holds the trachea open for air to pass through.
Intercostal muscles: Raises and lowers the ribs to help with breathing.
Ribs: Bones that protect the lungs.
Bronchi: Carries air from the trachea down to the bronchioles.
Bronchioles: Carries air from the bronchi down to the alveoli.
Alveoli: Tiny air sacs where gas exchange happens.
Diaphragm: Contracts and relaxes to increase and decrease the chest volume.

Hei Mahi (Do Now)

Think back to Year 10 Science. On your diagram, label as many structures as possible:
larynx, trachea, cartilage rings, intercostal muscles, ribs, bronchi, bronchioles, alveoli, diaphragm.

Exit Task

In your Learning Journal:

Re-write this interpreting question so it is asking about the Structure and Function of the Lung System.

How do the parts influence the whole?

Then, write an answer for it.

Exit Task

In your Learning Journal:

Re-write this interpreting question so it is asking about cartilage rings.

What does it remind you of?

Then, write an answer for it.

The human lung system is made up of various structures that work together to air into and out of the lungs, as well as get OXYGEN into the blood and CARBON DIOXIDE out of the blood (gas exchange).

As the airways get smaller and smaller in diameter, they increase in numbers.

The largest airway is the TRACHEA, and there is only one. The trachea is lined with C-shaped cartilage rings. The rings allow the trachea tube to stay open and not collapse, allowing oxygenated air to enter the lungs as well and exhaled air to exit the body.

The smallest airways are the BRONCHIOLES, of which there are around 60,000!

These numerous bronchioles lead to around 600 million ALVEOLI!

Having so many alveoli increases the surface area that can do gas exchange.

The alveolar walls are also very thin and moist, and they are also surrounded by many of tiny CAPILLARIES. This allows efficient diffusion of oxygen and carbon dioxide to exchange.