Question

Which of the following is the CORRECT order of events for muscle contractions?

A) The motor cortex of the brain sends a message→action potential sent down the axon→ACh attaches to the nicotinic ACh receptors on the motor end plate.
B) ACh from the axon terminal goes to the synaptic cleft→action potential sent down the axon→muscle contraction.
C) ACh attaches to the nicotinic ACh receptors on the motor end plate→action potential sent down the axon→muscle contraction.
D) The motor cortex of the brain sends a message→ACh attaches to the nicotinic ACh receptors on the motor end plate→action potential reaches the presynaptic terminal.
E) None of the above.

Answer 1

The correct sequence for muscle contraction starts with a signal from the brain's motor cortex, followed by an action potential traveling down the motor neuron, release of ACh, binding of ACh to receptors on the muscle fiber, and the initiation of muscle contraction.

Step-by-step explanation:

The correct order of events for muscle contractions is as follows:

1. The motor cortex of the brain sends a message.
2. An action potential is sent down the axon of the motor neuron.
3. Acetylcholine (ACh) is released from the axon terminal into the synaptic cleft.
4. ACh attaches to the nicotinic ACh receptors on the motor end plate of the muscle fiber.
5. An action potential is initiated in the muscle fiber, leading to muscle contraction.

This sequence is necessary for proper communication between the nervous system and the skeletal muscle, ultimately resulting in muscle contraction.