Question

Describe the process of breathing.

Answer 1

Breathing:

1. The process of taking in air rich in oxygen and giving out air rich in carbon dioxide is called breathing.
2. The process of taking in air that is rich in oxygen is called inhalation whereas the process of expelling out air that is rich in carbon dioxide is known as exhalation.

Inhalation:

1. The process of intake of atmospheric air is known as inhalation.
2. An increase in the volume of the thoracic cavity causes a decrease in the air pressure due to which inhalation takes place.
3. Contraction of rib muscles pulls the ribs upward and outward which increases the volume of the thoracic cavity.
4. The size of the thoracic cavity also increases due to the contraction of the diaphragm.
5. Due to the increase in the volume of the thoracic cavity, the air pressure inside the lungs decreases, and air rushes inside.

Exhalation:

1. The process of exhaling carbon dioxide-rich air is called exhalation.
2. It occurs when the size of the thoracic activity decreases and the air pressure inside the lungs increases.
3. For this to happen the ribs move downwards and inwards.
4. This leads to a reduction in the size of the thoracic cavity. The diaphragm relaxes and becomes dome-shaped.
5. The lungs compress and the air moves out.