Question

Lung ventilation movements are due to

• A. Costal muscles and diaphragm
• B. Costal muscles
• C. Diaphragm
• D. Wall of the lungs

Answer 1

The correct option is A Costal muscles and diaphragm

The diaphragm is the main muscle and does 99% of the work of breathing in a healthy, normal individual. It is located at the bottom of the rib cage. When it contracts, it creates a negative pressure in the upper chest cavity, which expands the lungs, drawing air in. When the diaphragm relaxes, exhalation occurs. The external intercostal muscles are used in forced inhalation. The internal intercostals are used in forced exhalation.

Hence the correct option is A.