This central part essential for life maintains the living organism's connection to the external environment and ensures the maintenance of basic life processes by connecting individual organs and systems. It builds the organism as a unified whole. The basic structural element of the nervous system is a nerve cell called a neuron. A neuron consists of two essential parts: the cell body and the protrusions, i.e. the axon and the dendrite.

Along the membrane of the dendrite, nerve impulses are conducted towards the nerve cell body, while the axon is a long unbranching protuberance that may be surrounded by a myelin sheath and carries information from the nerve cell body to synapses located at its ends.

Synapses are the site of transmission of excitation between nerve cells and other target cells, such as muscle cells. Each nerve cell receives information from other neurons, specialised cells such as sense organ receptors and directly from the external environment.

These are transmitted in the form of impulses that travel along the neuronal protuberances in a wave-like pattern. Disturbances in signal transmission are the cause of many neurological diseases, such as multiple sclerosis, Alzhaimer's disease or Parkinson's disease. Usually, signal transmission between cells is disrupted due to the loss of the myelin sheath, which is a form of insulator and ensures very fast transmission of impulses.