Question

During inspiration, air passes into lungs due to;

• A. Increase in volume of thoracic cavity and fall in lung pressure.
• B. Fall in pressure inside the lungs
• C. Increased volume of thoracic cavity
• D. Muscular expansion of lungs

Answer 1

The correct option is A

Increase in volume of thoracic cavity and fall in lung pressure.

Explanation for the correct answer	The correct answer is Option A: Inspiration leads to increase in the volume of the lungs which is caused due to contraction of diaphragm. During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. Increasing thoracic volume results in decreased pleural pressure. Increased alveolar volume, decreases alveolar pressure.
Explanation for the incorrect answer	All other options are wrong.
Final answer	During inspiration, air passes into lungs due to increase in volume of thoracic cavity and fall in lung pressure.