Question

Endplate junction is present between
A. Neuron and Striated muscle.
B. Neuron and Neuron
C. Muscle and muscle
D. Both B and C

Answer 1

Hint: The motor endplate junction is a chemical synaptic junction that is responsible for the transmission of signals in form of impulses to muscle fibre to bring about muscle contraction.

Step by step answer:Striated muscles are the muscles which when observed under a microscope show actin and myosin filaments or light and dark striations hence named striated muscles. The junction between a motor neuron and the sarcolemma (plasma membrane muscle fibre) is called the neuromuscular junction or motor endplate. In other words, the area of contact between the fibre of skeletal muscle and the myelinated nerve fibres. It is also called a myoneural junction. It is the chemical site of communication between the muscle cell and nerve fibre. The endplate is found at the terminal end of the muscle for the neural signal reaching the synapse transmits the information to another neuron by generating action potential in the latter, similarly, a neural signal reaching the neuromuscular junction releases a neurotransmitter(e.g.: acetylcholine) that generates the action potential in the sarcolemma. The endplate has thousands of receptors present in it.
Hence, option A is correct.
Additional Information: Acetylcholinesterase is present in the postsynaptic neuron. It breaks down acetylcholine into acetate and choline and terminates the action of the transmitter. Norepinephrine secreted by the sympathetic neural system and also by some neurons of the Central Nervous System is inactivated by enzyme monoamine oxidase.

Note: The junction between a nerve fibre and muscle fibre is called the neuromuscular junction. It can be said to be analogous to the synapse between two neurons. Neuromuscular diseases are those diseases that are caused because of the transmission issue between the muscle cell and nerve cells.