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What sequence of events correctly describes the role of calcium ions in muscle contraction?
- a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.
- b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.
- c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.
- d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.
Correct answer is option 'E'. Can you explain this answer?
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What sequence of events correctly describes the role of calcium ions i...
Understanding Muscle Contraction and Calcium Ions
Muscle contraction is a complex process that involves several key steps, particularly the role of calcium ions. Here’s a detailed breakdown:
1. Action Potential Initiation
- Upon stimulation, a motor neuron generates an action potential.
- This electrical signal travels along the neuron to the neuromuscular junction.
2. Calcium Ion Release
- The arrival of the action potential at the neuromuscular junction causes the release of calcium ions (Ca2+) from the sarcoplasmic reticulum (SR) within the muscle fiber.
- This release is crucial for activating the contraction mechanism.
3. Activation of Actin and Myosin Interaction
- The released calcium ions bind to troponin, a regulatory protein on the actin filaments.
- This binding causes a conformational change, moving tropomyosin away from the actin binding sites.
4. Cross Bridge Formation
- With the binding sites exposed, myosin heads can attach to the actin filaments, forming cross bridges.
- This interaction is essential for muscle contraction to occur.
5. Muscle Contraction
- Once the cross bridges form, the myosin heads pivot, pulling the actin filaments towards the center of the sarcomere, leading to muscle contraction.
- ATP is then required to detach the myosin from actin and reset the cycle.
Conclusion
In summary, the correct sequence of events is that calcium ions are released in response to an action potential, activating actin to interact with myosin, thus forming cross bridges and resulting in muscle contraction. This intricate process highlights the crucial role of calcium ions in muscle physiology.
Muscle contraction is a complex process that involves several key steps, particularly the role of calcium ions. Here’s a detailed breakdown:
1. Action Potential Initiation
- Upon stimulation, a motor neuron generates an action potential.
- This electrical signal travels along the neuron to the neuromuscular junction.
2. Calcium Ion Release
- The arrival of the action potential at the neuromuscular junction causes the release of calcium ions (Ca2+) from the sarcoplasmic reticulum (SR) within the muscle fiber.
- This release is crucial for activating the contraction mechanism.
3. Activation of Actin and Myosin Interaction
- The released calcium ions bind to troponin, a regulatory protein on the actin filaments.
- This binding causes a conformational change, moving tropomyosin away from the actin binding sites.
4. Cross Bridge Formation
- With the binding sites exposed, myosin heads can attach to the actin filaments, forming cross bridges.
- This interaction is essential for muscle contraction to occur.
5. Muscle Contraction
- Once the cross bridges form, the myosin heads pivot, pulling the actin filaments towards the center of the sarcomere, leading to muscle contraction.
- ATP is then required to detach the myosin from actin and reset the cycle.
Conclusion
In summary, the correct sequence of events is that calcium ions are released in response to an action potential, activating actin to interact with myosin, thus forming cross bridges and resulting in muscle contraction. This intricate process highlights the crucial role of calcium ions in muscle physiology.
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What sequence of events correctly describes the role of calcium ions i...
The sequence begins when a motor neuron's signal generates an action potential in the muscle fiber. This event triggers the release of calcium ions from the sarcoplasmic reticulum. These calcium ions then activate actin, allowing it to bind to myosin heads, forming cross bridges. The formation of these cross bridges enables the actin filaments to slide over the myosin filaments, causing the muscle to contract. Once contraction is completed, calcium ions are reabsorbed into the sarcoplasmic reticulum, actin becomes inactivated, cross bridges are broken, and the muscle relaxes.
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What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. Can you explain this answer?
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What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. 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 What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. Can you explain this answer?.
What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. 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 What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for What sequence of events correctly describes the role of calcium ions in muscle contraction?a)Calcium ions bind directly to myosin, initiating muscle contraction without the formation of cross bridges.b)Calcium ions are released from the sarcoplasmic reticulum, activating myosin to form cross bridges with actin.c)Upon an action potential in the muscle fiber, calcium ions are released from the sarcoplasmic reticulum, activating actin to bind with myosin and form cross bridges, resulting in muscle contraction.d)Calcium ions activate the motor neuron to generate an action potential that leads to muscle contraction.Correct answer is option 'E'. Can you explain this answer?.
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