CNS central nervous system

Synonyms

brain, spinal cord, meninges

  • Logical thinking
  • The own consciousness
  • Emotions / Feelings
  • And various learning processes.

Communication of nerves

When one speaks of nerve cells communicating with each other, this is essentially done by releasing chemical messengers (transmitters, neurotransmitters) into the vicinity of another nerve cell (neuron). The process is therefore similar to a simple conversation between two people. One person pours out words that the other processes.

Such a small functional unit is called a synapse. Most neurons carry thousands of such information interfaces (synapses)!

  • Nerve ending (Axon)
  • Messenger substances, e.g. dopamine
  • Other nerve ending (dendrite)

Thus, the incoming information (afference) is mostly settled at tree-like protuberances of the nerve cell (dendrites) and becomes efference through an axon!

Within a single nerve cell, the information is not transmitted by transmitters, but electrically via a current flow (action potential). A nerve cell has many dendrites, which are a kind of connecting cable to other nerve cells to communicate with them.

  • Nerve cell
  • Dendrite

Microscopic Anatomy

In the CNS, a basic distinction is made between a grey tissue substance (Substantia grisea) and a white tissue substance (Substanzia alba). This classification refers to the proportion of nerve cells at each point in the body. The grey matter contains the nerve cell bodies (perikaryas, soma), an apparently confused mass of nerve processes (neuropil) and above all astrocytes (connective tissue cells), which belong to the so-called glial cells.

Within the grey matter, the nerve extensions (connecting lines) are often not surrounded by oligodendrocytes with their cell extensions and thus are not myelinated (see myelination, nerve sheaths), i.e. they do not possess a nerve sheath. On the other hand, the white substance contains bundles of nerve cell fibers (connecting lines), which are usually myelenized by oligodendrocytes, i.e. they have an inherited sheath. This is where the white substance got its name: the myelin sheath contains plenty of fat, so that it has a whitish shimmer and stands out from the surrounding tissues in terms of color.