AIIMS2019Zoology-Human Physiology

AIIMS 2019 Zoology Muscle Contraction Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 11

Na and K concentration changes across the muscle cell membrane resulting in development of potential difference. So, Na and K ions are necessary for muscle contraction. Thus, both assertion and reason are true.

A

Both assertion and reason are true

B

Both assertion and reason are false

C

Assertion is true, reason is false

D

Assertion is false, reason is true

Correct Answer

Option A

Detailed Explanation

Both the assertion and reason are true because the concentration gradients of Na⁺ and K⁺ across the muscle cell membrane are crucial for generating the action potential, which initiates muscle contraction. The influx of Na⁺ ions depolarizes the membrane, while the efflux of K⁺ ions repolarizes it, allowing for the cycle of contraction and relaxation. Option B is incorrect as both statements are true, while options C and D are incorrect because they misrepresent the validity of the assertion and reason. Understanding the role of these ions in muscle physiology is essential for grasping how electrical signals lead to muscle movement.

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