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Which of the following statements about the mechanism of muscle contraction are correct?
A. Acetylcholine is released when the neural signal reaches the motor end plate.
B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.
C. During muscle contraction, the isotropic band gets elongated.
D. Repeated activation of the muscle can lead to accumulation of lactic acid.
- a)B and C are correct.
- b)A and D are correct.
- c)A, Band C are correct.
- d)A and C are correct.
Correct answer is option 'B'. Can you explain this answer?
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Verified Answer
Which of the following statements about the mechanism of muscle contra...
Following are the correct statements about the mechanism of muscle contraction:
(i) Acetylcholine is released when the neural signal reaches the motor end plate.
(ii) Repeated activation of the muscles can lead to lactic acid accumulation.
So, the correct answer is (B).
(i) Acetylcholine is released when the neural signal reaches the motor end plate.
(ii) Repeated activation of the muscles can lead to lactic acid accumulation.
So, the correct answer is (B).
Most Upvoted Answer
Which of the following statements about the mechanism of muscle contra...
Mechanism of Muscle Contraction
Muscle contraction is a complex physiological process involving various steps. Some of the important steps involved in muscle contraction are:
1. Initiation of Neural Signal
- Muscle contraction is initiated by a neural signal sent by the central nervous system (CNS) via a motor neuron.
- The motor neuron releases the neurotransmitter acetylcholine (ACh) when it reaches the motor end plate of the muscle fiber.
2. Generation of Action Potential
- The binding of ACh to the receptors on the motor end plate triggers the generation of an action potential (AP) in the muscle fiber.
- The AP propagates along the sarcolemma (cell membrane of the muscle fiber) and reaches the transverse tubules (T-tubules).
3. Release of Calcium Ions
- The depolarization of the T-tubules triggers the opening of the voltage-gated calcium channels in the sarcoplasmic reticulum (SR).
- The calcium ions (Ca2+) are released from the SR into the sarcoplasm (cytoplasm of the muscle fiber).
4. Binding of Calcium Ions to Troponin
- The calcium ions bind to troponin, a regulatory protein present on the actin filament.
- This binding causes a conformational change in troponin that shifts the position of tropomyosin, another regulatory protein, exposing the myosin binding sites on the actin filament.
5. Formation of Cross-bridges
- The myosin heads of the thick filament bind to the exposed myosin binding sites on the actin filament, forming cross-bridges.
- The energy released by the hydrolysis of ATP by the myosin heads is used to move the myosin heads towards the center of the sarcomere (contractile unit of the muscle fiber).
6. Sliding of Filaments
- The movement of the myosin heads causes the sliding of the actin and myosin filaments past each other, resulting in the shortening of the sarcomere.
- This shortening of the sarcomere leads to the contraction of the muscle fiber.
7. Relaxation of Muscle
- The relaxation of the muscle fiber occurs when the action potential ceases, and the calcium ions are pumped back into the SR by the calcium-ATPase pumps.
- The removal of calcium ions from troponin causes the tropomyosin to shift back to its original position, covering the myosin binding sites on the actin filament.
8. Accumulation of Lactic Acid
- Repeated activation of the muscle can lead to the accumulation of lactic acid due to the breakdown of glucose in the absence of oxygen (anaerobic respiration).
- This lactic acid can cause fatigue and muscle soreness.
Correct Answer: B (Muscle contraction is initiated by a signal sent by the CNS via a sensory neuron.)
Muscle contraction is a complex physiological process involving various steps. Some of the important steps involved in muscle contraction are:
1. Initiation of Neural Signal
- Muscle contraction is initiated by a neural signal sent by the central nervous system (CNS) via a motor neuron.
- The motor neuron releases the neurotransmitter acetylcholine (ACh) when it reaches the motor end plate of the muscle fiber.
2. Generation of Action Potential
- The binding of ACh to the receptors on the motor end plate triggers the generation of an action potential (AP) in the muscle fiber.
- The AP propagates along the sarcolemma (cell membrane of the muscle fiber) and reaches the transverse tubules (T-tubules).
3. Release of Calcium Ions
- The depolarization of the T-tubules triggers the opening of the voltage-gated calcium channels in the sarcoplasmic reticulum (SR).
- The calcium ions (Ca2+) are released from the SR into the sarcoplasm (cytoplasm of the muscle fiber).
4. Binding of Calcium Ions to Troponin
- The calcium ions bind to troponin, a regulatory protein present on the actin filament.
- This binding causes a conformational change in troponin that shifts the position of tropomyosin, another regulatory protein, exposing the myosin binding sites on the actin filament.
5. Formation of Cross-bridges
- The myosin heads of the thick filament bind to the exposed myosin binding sites on the actin filament, forming cross-bridges.
- The energy released by the hydrolysis of ATP by the myosin heads is used to move the myosin heads towards the center of the sarcomere (contractile unit of the muscle fiber).
6. Sliding of Filaments
- The movement of the myosin heads causes the sliding of the actin and myosin filaments past each other, resulting in the shortening of the sarcomere.
- This shortening of the sarcomere leads to the contraction of the muscle fiber.
7. Relaxation of Muscle
- The relaxation of the muscle fiber occurs when the action potential ceases, and the calcium ions are pumped back into the SR by the calcium-ATPase pumps.
- The removal of calcium ions from troponin causes the tropomyosin to shift back to its original position, covering the myosin binding sites on the actin filament.
8. Accumulation of Lactic Acid
- Repeated activation of the muscle can lead to the accumulation of lactic acid due to the breakdown of glucose in the absence of oxygen (anaerobic respiration).
- This lactic acid can cause fatigue and muscle soreness.
Correct Answer: B (Muscle contraction is initiated by a signal sent by the CNS via a sensory neuron.)
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Community Answer
Which of the following statements about the mechanism of muscle contra...
Acetylcholine is a neurotransmitter..so it is released when neural signal reaches the motor end plate. so option A is correct..
Muscle contraction is initiated by a signal sent by CNS via motor neuron ( refer NCERT: mechanism of muscle contraction)..so B is wrong..
During muscle contraction size of Isotropic band get shortened..so C is wrong..
lactic acid is a metabolic byproduct i.e released during intense exercise..D is correct..
Muscle contraction is initiated by a signal sent by CNS via motor neuron ( refer NCERT: mechanism of muscle contraction)..so B is wrong..
During muscle contraction size of Isotropic band get shortened..so C is wrong..
lactic acid is a metabolic byproduct i.e released during intense exercise..D is correct..
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Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer?
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Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer? for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer?.
Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer? for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following statements about the mechanism of muscle contraction are correct?A. Acetylcholine is released when the neural signal reaches the motor end plate.B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.C. During muscle contraction, the isotropic band gets elongated.D. Repeated activation of the muscle can lead to accumulation of lactic acid.a)B and C are correct.b)A and D are correct.c)A, Band C are correct.d)A and C are correct.Correct answer is option 'B'. Can you explain this answer?.
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