Question

⭕ 50 points ⭕

internet intercostal muscles is required only for forceful inspiration. No intercostal muscles is required for expiration.

✓✓ Explain why answer is option c​

Answer 1

Question

Which of the following changes occur in diaphragm and inter costal muscles when expiration of the air takes place?

a) Internal intercostal muscles relax and diaphragm contracts

b) External intercostal muscles and diaphragm relax

c)Internal intercostal muscles contract and diaphragm relax

d)External intercostal muscles and diaphragm contract

Answer

During expiration,the air in the lungs is expelled out.  As a consequence,the external intercostal muscles and diaphragm relax.

• The ribs contract and move inwards and upwards,in turn their volume also decreases forcing the air out through nostrils

• The diaphragm relaxes and moves upwards increasing pressure inside the lungs

• Since,the pressure gradient inside lungs is greater than of the surroundings.As a result,air moves out.

Option b is correct

Answer 2

Answer:

The air in the lungs expells out during expiration.As a result,the external intercostal muscles and diaphragm relax.

So,Answer:-

B)External intercostal muscles and diaphragm relax.

This changes occur when expiration of air takes place.

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