Breathing and gas exchange- Yr 9

What is breathing?

The mechanical action of getting air in and out of the lungs

When you inhale, do your intercostal muscles contract or relax?

Contract, moving the ribs upwards

When you exhale, does your diaphragm relax and move upwards, or contract and move downwards?

Relaxes and moves upwards, relaxing the intercostal muscles and moving down and inwards

What are the key body parts of the gas exchange system?

Trachea, bronchus, bronchioles, alveoli, intercostal muscles and the diaphragm

What are the alveoli?

The alveoli are the tiny air sacs found at the end of bronchioles in your lungs. Gas exchange occurs here.

What happens in your alveoli?

• Oxygen moves into the blood and carbon dioxide is removed.

• This oxygen is needed for respiration to release energy from glucose which has been obtained from food.

• Carbon dioxide is a waste product in this process and must be removed.

What is the trachea also known as?

The windpipe. It is lined with ‘C’ shaped rings which keep it open at all times

What are the bronchi?

After the trachea splits in half, the bronchi lead to each lung

What are the intercostal muscles?

These muscles run between the ribs and form the chest wall. They contract and relax with the diaphragm when a person breathes.

What is a bronchiole?

Each bronchus splits again and again into thousands of smaller tubes called bronchioles which take the air deeper into the lungs.