Question

What is a synapse? Is the presynaptic cell always a neuron? Is the postsynaptic cell always a neuron? If not, what other cell type could it be? Assuming both the pre- and post-synaptic cells are neurons, which one releases active neurotransmitters into the synaptic cleft between them? 8. What are the three major functional classes of neurons that we discussed? Which is/ are found in the Peripheral Nervous System (PNS) and which is/are found in the Central Nerous System (CNS)?

Answer 1

A synapse is a junction between two nerve cells consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.

Yes. The presynaptic cell is always a neuron. The motor neuron is considered as a presynaptic cell which transmits signals to the receiver cell called postsynptic cell.

No. postsynaptic cell is not always a neuron because it is a receiver of the neurotransmitter message. So, it may be a neuron or it may be a another type of cell. For example, in the communication of motor neuron and a skeletal muscle, the motor neuron is considered the presynaptic cell and the skeletal muscle is the postsynaptic cell. Other cell type may be the Skeletal muscle.

Assuming presynaptic cell and postsynavtic cell are neurons, presynaptic cell releases active neurotransmitter into the synaptic cleft between them.