Synapse

A synapse (from the Greek “contact”, “connection”) is a contact between two nerve cells through which nerve impulses are transmitted. A synapse is formed between the axon terminal of one cell (presynaptic) and the dendrite or body of another cell (postsynaptic).

In the presynaptic cell at the end of the axon there are synaptic vesicles containing mediators - substances that ensure the transmission of nerve impulses. When an impulse arrives, the vesicles merge with the axon membrane and release the transmitter into the synaptic cleft.

The transmitter diffuses through the gap and interacts with receptors on the membrane of the postsynaptic cell, causing its depolarization. As a result, an action potential arises in the postsynaptic cell, and the nerve impulse is transmitted further.

Thus, a synapse is a functional connection between neurons that allows the transmission of information in the nervous system. The speed and accuracy of brain function depends on the efficiency of synaptic transmission.

A synapse is a structural and functional unit of the nervous system that ensures signal transmission from one nerve cell to another. Through synapses, information is transferred from excitation zones to inhibition zones and from dendrites to the axon body and then from the axoplasm to its terminals.

The mechanism of signal transmission through the synapse has a complex structure and includes several stages. First, the electrical activity of neurons is transmitted through electrotonic connections that exist between excitatory neurons and inhibitory neurons. If the excitatory neuron fires another cell, then the electrical current must reach the synapse located between these cells.

When the electric current reaches the synaptic cleft, it excites molecules of the enzyme acetylcholinesterase, which destroys the acetylcholine (neurotransmitter) substance. Acetylcholinemonesterase is a protein that breaks down the neurotransmitter, causing it to stop working. The nerve impulse rushes from the initiator cell to the receiver cell.

In order for the ionic current to return, the initiating cell, by analogy, must lose its energy. Ion channels are encoded in the genetic code and are determined primarily by regulators of gene expression. In a synthetic version, these were transmembrane proteins called voltage-gated ion channels.