Bark of the cerebral hemispheres

Components of the cerebral hemispheres are the brain cloak and subcortical ganglia. They surround their lateral ventricles.

Between the right hemisphere and the left there is a deep longitudinal furrow. In its depth is a corpus callosum. It is formed by nerve fibers.

The cortex of the cerebral hemispheres of the human brain is represented by a brain cloak. This gray matter is formed by nerve cells with outgrowths from them, and cells of neuroglia. It is believed that the latter perform a supporting function for neurons and participate in the metabolism of their substances.

The cortex of the cerebral hemispheres is the highest, from the phylogenetic point of view, the youngest formation of the central nervous system. The thickness of its layer is from one and a half to three millimeters. The cortex of the cerebral hemispheres is of the order of twelve to eighteen billion neurons.

Its general surface is increased due to the presence of numerous furrows. They divide the hemispheres into parts and convex convolutions. In each hemisphere there are four parts. They are formed due to three furrows: lateral, parietal-occipital and central. As a result, occipital, temporal, parietal and frontal lobes are formed.

The latter is located in front of the central furrow. The temporal lobe is confined to the central groove in front, at the bottom - lateral, parieto-occipital - behind. The temporal lobe is limited by a deep lateral sulcus at the top. The occipital lobe is located behind the parieto-occipital.

Above the corpus callosum is a white substance. It includes projection, commissural and associative fibers. The cortex of the large hemispheres has a two-way connection with the underlying CNS sections through the ascending and descending pathways. They include projection fibers that extend beyond the hemispheres.

Individual cortical areas have a functional different meaning. Along with this, the cortex of the large hemispheres works as a single whole. However, there is no strict functional localization in it. Experiments with animals showed that after the destruction of individual sections in the cortex, after a certain period of time, neighboring regions began to perform the functions of the destroyed areas. This feature is associated with high plasticity of cells.

The cortex of the hemispheres receives centripetal impulses from the receptor formations. For each receptor apparatus, there corresponds a site called IP. Pavlov's "cortical core analyzer." The areas of the cortex in which they are located are called sensory patches.

In the posterolateral and anterocenteral areas of the cortex is the nuclear region of the motor analyzer. It is carried out from the receptors of the tendons, skeletal muscles and joints excitation.

The area of the skin analyzer is located behind the central sulcus (in the posterolateral zone). It is associated with tactile, pain and temperature sensitivity.

The largest area is occupied by the area of analyzers of the face, voice apparatus, hands. The smallest area is allocated to the representative of the analyzers of the lower leg, hip and trunk.

In the occipital zone is the nuclear region of the visual analyzer, in the temporal region - the auditory. The region of the taste buds is located near the lateral groove.

Motion arises as a result of irritation, formed from interaction with sensory areas of the motor zone of the cortex. It is located from the central furrow anteriorly.

The nuclear regions of the analyzers are represented in the crust by areas in which most of their conducting paths terminate. Outside of them are scattered elements. They receive the impulses of the same receptors that enter the nucleus of the analyzer.