Question

Which of the following is the correct sequence of events for muscle contractions? a) neurotransmitter release, motor nerv,e action potential, muscle cell action potential, release of calcium ions from SR b) motor nerve action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, sliding of myofilaments c) neurotransmitter release, muscle cell action potential, motor nerve action potential, release of calcium ions from SR, release of iron d) muscle cell action potential neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments

Answer 1

The correct sequence of events for muscle contractions involves neurotransmitter release, motor nerve action potential, muscle cell action potential, release of calcium ions from the sarcoplasmic reticulum (SR), and sliding of myofilaments.

Step-by-step explanation:

The correct sequence of events for muscle contractions is:

1. Neurotransmitter release
2. Motor nerve action potential
3. Muscle cell action potential
4. Release of calcium ions from the sarcoplasmic reticulum (SR)
5. Sliding of myofilaments

First, the neurotransmitter acetylcholine (ACh) is released at the neuromuscular junction. This triggers a motor nerve action potential that travels along the sarcolemma and initiates a muscle cell action potential. The muscle cell action potential then triggers the release of calcium ions from the sarcoplasmic reticulum. Finally, the calcium ions bind to the actin filaments, allowing the myosin filaments to slide and generate muscle contraction.

Answer 2

The correct sequence of events for muscle contractions is: neurotransmitter release, muscle cell action potential, motor nerve action potential, release of calcium ions from SR, sliding of myofilaments.

Step-by-step explanation:

The correct sequence of events for muscle contractions is:

1. Neurotransmitter release (ACh)
2. Muscle cell action potential
3. Motor nerve action potential
4. Release of calcium ions from the sarcoplasmic reticulum (SR)
5. Sliding of myofilaments

First, acetylcholine (ACh) is released from the motor neuron into the neuromuscular junction, triggering depolarization.

Then, a muscle cell action potential is generated and travels along the sarcolemma.

This action potential triggers the release of calcium ions from the sarcoplasmic reticulum (SR).

Finally, the calcium ions bind to actin, causing the sliding of myofilaments and muscle contraction.