Question

Diaphragm is a thin muscular membrane that separates abdominal cavity from thoracic cavity. when diaphragm of man is completely dome shaped it shows

• A. End of expiration and beginning of inspiration.
• B. Beginning of expiration and of inspiration.
• C. Increased rate of breathing.
• D. Decreased rate of breathing.

Answer 1

The correct option is A End of expiration and beginning of inspiration.

The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. During exhalation, the diaphragm relaxes and returns to its dome shape, and air is forced out of the lungs.