Question

what are the main events occurring between the arrival of an action potential at a motor neuron end plate and contraction of the surrounding muscle

Answer 1

The main events between the arrival of an action potential at a motor neuron end plate and muscle contraction involve the release of acetylcholine, depolarization of the muscle fiber, release of calcium ions, and the interaction of thick and thin filaments in the sarcomere.

Step-by-step explanation:

The main events occurring between the arrival of an action potential at a motor neuron end plate and contraction of the surrounding muscle are as follows:

1. The arrival of an action potential at the motor neuron end plate causes the release of the neurotransmitter acetylcholine (ACh) into the synaptic cleft.
2. ACh binds to ACh receptors on the motor end plate of the muscle fiber, causing the muscle fiber to depolarize.
3. This depolarization triggers the release of calcium ions (Ca++) from the sarcoplasmic reticulum (SR) in the muscle fiber.
4. The calcium ions bind to troponin, causing a conformational change in the sarcomere.
5. This conformational change allows the interaction between the thick and thin filaments of the sarcomere, leading to muscle contraction.