Page 380 - Primary Six Notes

During the process of swallowing, the epiglottis moves to cov-

er the trachea to ensure that food enters the oesophagus and

to prevent choking.

6. The trachea (windpipe)

 The main function of the trachea is to provide airway for air

to enter and exit the lungs. It has an epiglottis that protects

the opening of the trachea when swallowing food. Epiglottis

prevents choking.

 Trachea contains rings of cartilage that prevents it from
closing and prevents suffocation.

7. Bronchi

 The bronchi are two air tubes that branch off of the trachea.

 Each of the tubes, the right bronchus and the left bronchus

leads to a lung and carries air directly into it.

8. Bronchiole

 Each bronchus divides and subdivides into smaller and
smaller branches, the bronchioles. The bronchiole tubes

lead to the lobes of the lungs.
 The main function of the bronchi and bronchioles is to carry

air from the trachea into the lungs.

 They also use the mucus and cilia to trap and move dust and

other contaminants away from the lungs.

9. The air sacs

This is where the exchange of gases takes place by diffusion.