Expiration involves-a)Contraction of diaphragm musclesb)Contraction of intercostal musclesc)Relaxation of diaphragm and intercostalmusclesd)Contraction of diaphragm and intercostalmusclesCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

Answer

Explanation:

Expiration:
Expiration refers to the process of air leaving the lungs during breathing out. This process involves the relaxation of the diaphragm and intercostal muscles.

Relaxation of Diaphragm Muscles:
- During expiration, the diaphragm muscles relax. The diaphragm, which is a dome-shaped muscle located at the base of the lungs, moves upward as it relaxes. This upward movement decreases the volume of the thoracic cavity, causing an increase in pressure within the lungs.
- The increased pressure within the lungs forces the air to be pushed out of the lungs, resulting in expiration.

Relaxation of Intercostal Muscles:
- In addition to the relaxation of the diaphragm muscles, the intercostal muscles also relax during expiration. The intercostal muscles are located between the ribs and help in the expansion and contraction of the ribcage during breathing.
- When these muscles relax, the ribcage moves downward and inward, further reducing the volume of the thoracic cavity and aiding in the expulsion of air from the lungs.
Therefore, during expiration, both the diaphragm and intercostal muscles relax, leading to the expulsion of air from the lungs.

Answer

Expiration involves relaxation of diaphragm and intercostal muscles:
- Expiration is the process of exhaling or breathing out air from the lungs.
- During expiration, the diaphragm and intercostal muscles relax, causing the volume of the thoracic cavity to decrease.
- This relaxation leads to a decrease in lung volume, which increases the pressure inside the lungs.
- As a result, air is expelled from the lungs, moving from an area of higher pressure to an area of lower pressure outside the body.
- The relaxation of the diaphragm and intercostal muscles allows the elastic recoil of the lungs to push air out of the respiratory system.
- The diaphragm, which is a dome-shaped muscle located at the base of the lungs, relaxes and moves upwards towards the chest cavity.
- The intercostal muscles, which are located between the ribs, also relax, allowing the rib cage to move inward.
- These combined movements decrease the volume of the thoracic cavity, increasing the pressure and causing expiration to occur.
- It is important to note that expiration is a passive process, meaning it does not require active muscular contraction like inspiration (breathing in) does.
- Instead, expiration relies on the relaxation of the diaphragm and intercostal muscles to allow the natural elastic recoil of the lungs to expel air.

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