Question

mechanisms of breathing explain​

Answer 1

Answer:

on taking air inside the body; lungs expand whereas on expelling air outside the body lungs shrink

Answer 2

★ INSPIRATION:-

→ Active intake of air from atmosphere into lungs.

→ During this, the diaphragm contracts causing an increase in vertical volume.

→ Contraction of external intercostal muscles lifts up the ribs and sternum causing an increase in thoracic volume in the dorso-ventral axis.

→ These changes reduce pressure inside the thorax causing the expansion of lungs. Thus pulmonary volume increases resulting in decrease of intra-pulmonary pressure to less than the atmospheric pressure. So air moves into lungs.

★ EXPIRATION:-

→ Passive expelling of air from the lungs.

→ During this, intercostal muscles & diaphragm relax causing a decrease in thoracic volume and there by pulmonary volume. So air moves out.

→ During forceful expiration, abdominal muscles and internal inter-costal muscles contract.