Gray and white matter of the brain

The human brain is composed of white and gray matter. The first is all that is filled between the gray matter on the cortex and the basal nuclei. On the surface there is an even layer of gray matter with nerve cells, the thickness of which is up to four and a half millimeters.

Let's study in more detail what a gray and white substance is in the brain.

What do these substances consist of?

The substance of the central nervous system is of two types: white and gray.

White substances consist of a variety of nerve fibers and processes of nerve cells, the shell of which is white.

Gray matter consists of nerve cells with processes. Nerve fibers connect different parts of the central nervous system and nerve centers.

Gray and white matter of the spinal cord

The heterogeneous substance of this organ is gray and white. The first is formed by a huge number of neurons, which are concentrated in the nucleus and come in three types:

• Radicular cells;
• Beam neurons;
• Internal cells.

The white matter of the spinal cord is surrounded by a gray matter. It includes the nerve processes that make up three systems of fibers:

• Intercalary and afferent neurons that connect different parts of the spinal cord;
• Sensitive afferent, which are long centripetal;
• Motor afferent or long centrifugal.

Medulla

From the course of anatomy we know that the spinal cord turns into an oblong one. Part of this brain is thicker than the bottom. Its average length is 25 millimeters, and the shape resembles a truncated cone.

It develops gravitational and auditory organs associated with breathing and circulation of blood. Therefore, the core of gray matter here regulate balance, metabolism, circulation, breathing, coordination of movements.

Hindquarters

This brain consists of a bridge and a cerebellum. Consider the gray and white matter in them. The bridge is a large white roller on the back side of the base. On one side, its border with the legs of the brain is expressed, and on the other hand it is oblong. If you make a cross-section, the white matter of the brain and the gray core here will be seen very well. Transverse fibers divide the bridge into the ventral and dorsal areas. In the ventral part, the white matter of the conducting paths is mainly present, while the gray forms its nuclei here.

The dorsal part is represented by nuclei: switching, reticular formation, sensory systems and cranial nerves.

The cerebellum is under the occipital lobes. It includes the hemisphere and the middle part called "worm". The gray matter consists of the cerebellar cortex and nuclei, which are hipped, spherical, cork-shaped, and serrated. The white matter of the brain in this part is located under the bark of the cerebellum. It penetrates all the convolutions as white plates and consists of different fibers, which either bind the lobules and convolutions, or are directed toward the inner nuclei, or join the brain sections.

Middle Brain

It starts from the middle cerebral bubble. On the one hand it corresponds to the surface of the brainstem between the pineal gland and the upper cerebral sail, and on the other - the area between the mastoid bodies and the front part of the bridge.

It includes a brain water pipe, on one side of which the boundary is provided by the roof, and on the other - by the covering of the legs of the brain. On the ventral area, the rear perforated substance and the legs of the large brain are distinguished, and on the dorsal region there is a plate of the roof and the handles of the lower and upper tubercles.

If we consider the white and gray matter of the brain in the brain, we will see that the white surrounds the central gray matter, which consists of small cells and has a thickness of 2 to 5 millimeters. It consists of block, trigeminal and oculomotor nerves together with the additional nucleus of the latter and the intermediate one.

Intermediate brain

It is located between the corpus callosum and the vault, and on the sides it fuses with the terminal brain. The dorsal part consists of the visual hillocks, on the upper part of which there is an over-the-hill, and in the ventral zone there is a lower-bogornaya region.

Gray matter here consist of nuclei, which are connected with the centers of sensitivity.
White substances are represented by conducting paths of different directions, which guarantee the connection of formations with the cortex and nuclei. The hypothalamus and epiphysis also enter the intermediate brain.

The Ultimate Brain

It is represented by two hemispheres, which separate the gap that runs along them. It connects in depth with a corpus callosum and spikes.

The cavity is represented by lateral ventricles located in one and the second hemisphere. These hemispheres consist of:

• Cloak of the neocortex or six-layered cortex, differing in nerve cells;
• Striped body from basal nuclei - ancient, old and new;
• Partitions.

But sometimes there is another classification:

• The olfactory brain;
• Subcortex;
• Gray matter of the bark.

Without touching the gray matter, we will stop immediately on white.

On the features of the white matter of the hemispheres

The white matter of the brain occupies the entire space between the gray and basal nuclei. Here there is a huge amount of nerve fibers. In white matter, the following sections are available:

• Central substance of the inner capsule, corpus callosum and long fibers;
• Radiant crown of divergent fibers;
• Semi-oval center in the outer parts;
• Substance in the gyrations between the furrows.

Nerve fibers are:

• Commissural;
• Associative;
• Projection.

The white matter includes nerve fibers, which are connected by the convolutions of one and the other cortex of the hemispheres and other formations.

Nerve fibers

Basically, commissural fibers are found in the corpus callosum. They are located in the brain commissures, which connect the cortex on different hemispheres and symmetrical points.

Fiber associative groups regions in one hemisphere. In this case, short connects adjacent gyruses, and long ones are located at a distant distance from each other.

Projection fibers connect the cortex with those formations that are located below, and further with the periphery.

If the inner capsule is viewed frontally in a section, the lenticular nucleus and the posterior leg will be visible. Projection fibers are divided into:

• Fibers located from the thalamus to the cortex and in the opposite direction, they excite the cortex and are centrifugal;
• Fibers directed to motor nerve nerves;
• Fibers that conduct impulses to the muscles of the whole body;
• Fibers directed from the cortex to the bridge nuclei, providing a regulating and inhibitory effect on the work of the cerebellum.

Those projection fibers that are closest to the cortex create a radiant crown. Then the main part of them passes into the inner capsule, where the white substance is between the tail and lenticular nuclei, as well as the thalamus.

On the surface there is an extremely complex pattern, where grooves and rollers alternate between them. They are called convolutions. Deep furrows divide the hemispheres into large areas, which are called the shares. In general, the furrows of the brain are deeply individual, they can vary very much in different people.

In the hemispheres there are five parts:

• Frontal;
• Parietal;
• Temporal;
• Occipital;
• island.

Furrow central originates at the top of the hemisphere and moves down and forward, to the frontal lobe. The site behind the central sulcus is parietal lobe, which ends in the parietal-occipital furrow.

The frontal lobe is divided into four convolutions, vertical and horizontal.
In the temporal lobe the lateral surface is represented by three convolutions, which are delimited from each other.

Furrows of the occipital lobe are variable. But all, as a rule, have a transverse, which is connected with the end of the furrow intertemporal.

On the parietal lobe there is a furrow running parallel to the central horizontally and merging with another furrow. Depending on their location, this proportion is divided into three gyruses.

The island has a triangular shape. It is covered with short gyrus.

Brain lesions

Thanks to the achievements of modern science, it became possible to conduct high-tech brain diagnostics. Thus, if there is a pathological focus in white matter, it can be identified at an early stage and in time prescribe therapy.

Among the diseases that are caused by the damage of this substance, its disorders in hemispheres, pathology of the capsule, corpus callosum and mixed syndromes are distinguished. For example, with injuries to the back of the leg, one-half of the human body can paralyze. This problem can develop with a sensitivity disorder or a visual field defect. Failures in the work of a corpus callosum lead to mental disorders. At the same time, a person ceases to recognize surrounding objects, phenomena, etc., or does not produce purposeful actions. If the focus is two-sided, swallowing and speech disorders may occur.

It is impossible to overestimate the importance of both gray and white matter in the brain. Therefore, the earlier the presence of pathology is revealed, the more likely that the treatment will be successful.