Q. Mark the correct pair of muscles involved in the normal breathing in humans.

 3128  186 Breathing and Exchange of Gases Report Error

Solution:

Breathing involves two stages : inspiration during which atmospheric air is drawn in and expiration by which the alveolar air is released out. Inspiration can occur if the. pressure within the lungs (intra-pulmonary pressure) is less than the atmospheric pressure, i.e., there is a negative pressure in the lungs with respect to atmospheric pressure. Similarly, expiratibn takes place when the intra-pulmonary pressure is higher than the atmospheric pressure. The diaphragm and a specialised set of muscles-external and internal intercostals between the ribs, help in generation of such gradients. So, the correct answer is 'Diaphragm and intercostal muscles'.