Gas exchange in humans

Humans have _ lungs that are situated side by side in the throax

2

What is the thorax

The chest - includes the lungs, heart, ribs…

Why do lungs have a spongy texture?

So they can increase in volume when air enters or decrease in volume when air is pushed out

What are the lungs surrounded by

The ribcage

What does the ribcage do for the lungs

Provides protection

What do you find running diagonally between the ribs?

Intercostal muscles

What do the intercostal muscles do?

They help move the ribcage

What are the lungs joined to the back of the mouth by

The trachea

Where is the epiglottis and what does it do?

The epiglottis is at the top of the trachea

It stops food or drink from entering the lungs

The trachea is divided into _ small tubes called…?

2 small tubes, called bronchi

What do the bronchi divide into

Smaller branches called bronchioles

What do the bronchioles lead to

Thin-walled air sacs called alveoli (where gas exchange occurs)

What are the trachea and bronchi lined with?

Rings of cartilage

What are rings of cartilage? What do they do?

A hard substance which keeps the trachea and bronchi in shape and stops them from collapsing when we breath in.

The trachea and bronchi are lined with specialized cells called…

ciliated cells and goblet cells

What do goblet cells do?

They secrete mucus to trap dust, pollen, bacteria and other foreign substances

What do the cilia do? What are the cilia?

Cilia are motile hair-like structures that beat in a coordinated manner to push the mucus along with the foreign particles upwards away from the lungs.

In the thorax, there is also a large domed sheet of muscle. What is it known as

The diaphragm

What happens when the diaphragm is relaxed?

It curves upwards

And when the diaphragm contracts?

It flattens and moves down, making the thorax bigger

Label the lungs