Neurocyte

Nerve cells. Their number is huge - up to 140 billion have nerve fibers of one person. They perceive irritations, transmit them to another part of the body and cause a motor reaction. If a nerve cell is damaged, it may die, and its location is quickly replaced by cellular elements.

The nerve cell has a special way of transmitting excitation using electrical impulses. Thanks to the special properties that are inherent in it, nervous tissue ensures rapid transmission of signals to the central nervous system. When an irritant appears, the membrane changes permeability. There is an ascending excitation along the axon, which is accompanied by the opening of calcium. It triggers the process of contraction of the axon cord. The impulse spreads to the membrane of the neuron, causing an electrical response - a discharge occurs. The excitation is transmitted to another nerve cell, which then releases an impulse. This process is repeated until the inhibitory neuron acts, stopping the next cell located behind it from receiving the nerve impulse. From here another calcium ion comes out, and the muscle duct relaxes.

The functions of the nervous system provide automatic and voluntary control of the motor activity of the body. Each fabric has special properties and the ability to perform one or another action. Nerve cells are present from birth. However, some areas of nerve tissue are missing. This happens for two reasons: due to their location in the pituitary gland, an area of ​​the brain, and in the anterior part of the brain stem. Of the missing zones, the most developed is the area of ​​the cerebral pons, which compensates for the missing area in the medulla oblongata to a certain extent. Vascular zones are not yet detected in the fetus, but begin to form during the development of the cerebral convolutions.

Every year more and more nerve cells and neurons develop. This leads to greater differentiation of functions as a result of the growth of a large number of connections between nerve cells. Connections are transmitted using axons, their long processes, their number and length depend on the function of the corresponding area of ​​the brain or spinal cord. In the cerebellum, the hemispheres are the most dense. A complex structure and a large number of axons are characteristic of the cerebral cortex.