Gray matter, also known as gray matter, is one of the two basic building blocks of the human central nervous system. It consists mainly of the bodies of nerve cells, whose task is in turn the ability to generate, process and transmit nerve impulses. Where is the gray matter located in the nervous system and what is its function?
Gray matter( gray matter , Latinsubstantia grisea ) is one of the two the basic tissues that make up the nervous system. The human nervous system can be divided in many different ways - there is the central and peripheral nervous system, the somatic nervous system and the autonomic system.
To divide the structures of one of the most important human organ systems can also be based on what exactly builds them. In this approach, we can distinguish two basic components that make up the nervous system: white matter and gray matter.
Both of the listed ones are closely connected with each other and in fact one without the other would not be able to fulfill their functions properly.
Gray matter (gray matter): structure
Gray matter is located completely differently in different parts of the central nervous system.
Within the brain, it is located primarily on its surface - because it covers the hemispheres of the brain and the hemispheres of the cerebellum. However, these are not the only places where gray matter is found in this part of the CNS. Its foci are also located inside the brain and are:
- hill
- hypothalamus
- basal kernels
- septum nucleus
- nuclei located within the cerebellum (toothed, conical, ball-shaped and top nuclei)
- black substance
- red nucleus
- olive kernel
- nuclei of cranial nerves
See also: Paralysis of cranial nerves
The distribution of gray matter in the spinal cord is slightly different. For in it it is not on top, but is located in its central part, and there the gray matter is surrounded by white matter. Gray matter strands in cross sectionthey resemble the letter H and individual of them are referred to as the front horns, the back horns and the lateral horns (the latter ones extend only at the height of the thoracic part of the spinal cord).
So far it has not been explained where this and no other definition of gray matter comes from. Well, it owes its name, as it is easy to guess, a specific color - in the foci of the gray matter there are few myelin fibers, which, thanks to the myelin sheath, have a bright color, and many nerve cells are in them.
In fact, the gray matter is not strictly gray, but rather very light-grayish, and additionally yellowish-pinkish spots appear within it, which is caused by the presence of blood vessels in it.
Gray matter (gray matter): role in the functioning of the nervous system
The basic element of the gray matter are nerve cells (neurons), in addition to them, there are also cells supporting the former, which are glial cells.
Within the gray matter there are various centers that perform separate functions: some of them are responsible for controlling the course of our movements, others are related to the processes of speaking, and still others are responsible for the ability to receive information from the outside world through our sensory organs.
Gray matter foci in the spinal cord are organized in a specific way: the functional separation of the gray matter is clearly visible there.
Within the front horns there are nerve cells, whose role is to control our movements - motor neurons are present in them. In the posterior horns there are sensory neurons, which are reached by various sensory stimuli, which allows us to feel, for example, heat, pain or touch.
Gray matter (gray matter): diseases
The development of the gray matter essentially begins as the entire nervous system begins to form. In fact, however, it does not end when a human is born, and continues for several years after birth - usually it is mentioned that the final completion of gray matter development takes place shortly after the beginning of the second decade of life.
It is completely natural that gray matter gradually degrades with the passage of time - this phenomenon is responsible for the fact that in the elderly there is a gradual deterioration of memory and motor skills. However, some factors may accelerate the degeneration of gray matter and lead tothe occurrence of various neurological deficits.
The destruction of nerve cells is related to, for example, alcohol abuse. The use of other psychoactive substances can also have a destructive effect on the amount of gray matter in the central nervous system.
It has already been described, inter alia, the fact that long-term use of marijuana can reduce the amount of gray matter in certain areas of the brain, such as the amygdala, hippocampus, and temporal cortex.
The loss of nerve cells belonging to the gray matter can also lead to various diseases, such a problem may appear, among others after suffering a stroke (which may result in the death of some neurons belonging to the gray matter).