Page 376 - Primary Six Notes

Respiration is the process by which the body uses food and ox-

ygen to produce energy, carbon dioxide and water vapour. Res-

piration takes place in body cells. It is the action of breathing.

The by-products of respiration are:

1. Oxygen

2. Carbon dioxide

3. Water vapour

Breathing

Breathing is the constant exchange of gases between an organ-

ism and the surroundings. It is the taking of air in and out.

Types of breathing

1. Inspiration (breathing in) inhalation. This is the passage of

air into the lungs to supply the body with oxygen.

2. Expiration (breathing out) exhalation. This is the passage of

air out of the lungs to expel carbon dioxide.

What happens during inspiration / inhalation?

1. The volume of the chest and lungs increases.

2. Diaphragm and intercostal muscles contracts.

3. Ribs move upwards and outwards.

4. The lungs expand.

What happens during expiration /exhalation?

1. The volume of the chest and lungs decreases.

2. The diaphragm and intercostal muscles relax.