Question

Put the following events that occur at the neuromuscular junction in their correct order. A-Sodium enters the muscle fiber, creating an end-plate potential. B-Neurotransmitter is released into the synaptic cleft. C-An action potential reaches the presynaptic membrane. D-Neurotransmitter binds to a receptor on the postsynaptic membrane. E-Sodium channels on the motor end plate open.

Answer 1

Answer:

C-An action potential reaches the presynaptic membrane.

E-Sodium channels on the motor end plate open.

A-Sodium enters the muscle fiber, creating an end-plate potential.

B-Neurotransmitter is released into the synaptic cleft.

D-Neurotransmitter binds to a receptor on the postsynaptic membrane.

Explanation:

In the neuromuscular junction, there is a presynaptic membrane, a postsynaptic membrane, and between these two, there is a gap called the synaptic cleft.

First, an action potential reaches the presynaptic membrane, causing the opening of sodium channels and the entering of Sodium ions to the muscle fiber creating an endplate potential. As a consequence of this, the neurotransmitters contained in vesicles travel down up to the presynaptic membrane, where they release their content into the synaptic cleft. Then, the neurotransmitters bind to the receptors in the ion channels of the postsynaptic terminal. This causes the opening of the ion channels and a rush of ion Sodium to the inside of the postsynaptic membrane, creating an action potential that will travel from cell to cell.