Which of the Following is the Motor Endplate

Question

Which of the following is the motor endplate?
A)the terminal membrane of the motor neuron where neurotransmitter is released
B)the portion of the membrane of the muscle cell that has postsynaptic receptors that respond to the neurotransmitter released by the motor neuron
C)the membrane of the sarcoplasmic reticulum where calcium is stored
D)the Z disc where two sarcomeres adjoin

Accepted Answer

The motor endplate refers to the portion of the membrane of the muscle cell that has postsynaptic receptors that respond to the neurotransmitter released by the motor neuron. This is where the chemical signal from the motor neuron is converted to an electrical signal in the muscle cell, leading to muscle contraction. The terminal membrane of the motor neuron where neurotransmitter is released is called the presynaptic membrane. The membrane of the sarcoplasmic reticulum where calcium is stored is called the SR membrane. The Z disc where two sarcomeres adjoin is a structural component of the sarcomere.