What is a synapse?

Answer 1

There are several types of synapses in the body. The most commonly discussed type is the chemical synapse, but other types of synapses include electrical synapses and immunological synapses. Because chemical synapses are the most commonly discussed synapses in general, that's probably what this question is referring to.

A chemical synapse is a small gap, or commonly referred to as a connection, between two cells that allows for the first cell (the presynaptic cell) to communicate with the second cell (the postsynaptic cell) through a chemical signal. These chemical signals are called neurotransmitters, and once they are released by the presynaptic cell, they act on the postsynaptic cell through specialized protein molecules called neurotransmitter receptors.

The actions triggered by a neurotransmitter binding its receptor on the postsynaptic cell are highly varied. They vary according to the type, quantity, and frequency of neurotransmitter release, the specific receptor involved, the type of cell that is receiving the neurotransmitter signal, among other things. For example, a neurotransmitter called glutamate typically causes activation of the postsynaptic cell, while a neurotransmitter called GABA typically inhibits postsynaptic cells. Likewise, if the postsynaptic cell belongs to a gland, then activity in that cell may promote secretion, while inhibition may hinder secretion. If the postsynaptic cell is a muscle fiber, then activation triggers muscle contraction, while inhibition causes relaxation.

A synapse is a connection which allows for the transmission of nerve impulses. Synapses can be found at the points where nerve cells meet other nerve cells, and where nerve cells interface with glandular and muscular cells. In all cases, this connection allows for the one-way movement of data. The human body contains trillions of synapses, and at any given time, huge numbers of these connections are active.