Biology AS

Explain the process of inspiration (6)

1. External intercostal muscles contract while internal intercostal muslces relax

2. Ribs are pulled upwards & outwards increasing the volume of the thorax

3. Diaphragm muscles contract causing it to flatten which also increases the volume of the thorax

4. Increased volume of the thorax results in reduction of pressure in the lungs

5. Atmospheric pressure is now greater than pulmonary pressure

6. Air is forced out of the lungs

Give the unit & equation of the process pulmonary ventilation

Unit - dm^3min-1

Equation - Tidal Volume * Ventilation Rate