Question

Define the following:
Breathing

Answer 1

Breathing:

1. The process, by which air is drawn in from the atmosphere into the lungs and forced out from the lungs back into the atmosphere is known as breathing.
2. It involves two steps-inhalation and exhalation.

Inhalation:

1. Inhalation or inspiration involves the taking of atmospheric air into the lungs.
2. During inhalation, external intercostal muscles of the ribs contract and pull them upward and outwards to increase the volume of the thoracic cavity.

Exhalation:

1. Exhalation involves the expulsion of air from the lungs into the atmosphere.
2. During exhalation, internal intercostal muscles contract and the ribs move downwards and inwards.