The ultimate brain: structure and function

The big (finite) brain in the course of evolution appeared later than other departments. Its size and mass are much larger than other segments. The article will present his photo. The human brain is associated with the most complex manifestations of intellectual and mental activity. The organ has a rather complex structure. Next, we consider the structure of the final brain and its problems.

Structure

The department under consideration includes two large segments. The hemispheres of the terminal brain are connected to each other by means of a corpus callosum. Between these segments are also spikes: arch, rear and front. Considering the structure of the final brain, you should pay attention to the cavity in this department. They form the lateral ventricles: left and right. Each of them is located in the corresponding segment. One of the walls of the ventricles is formed by a transparent septum.

Segments

The hemisphere covers the bark from above. It is a layer of gray matter that is formed by neurons of more than 50 species. Under the bark is a white substance. It consists of myelinated fibers. Most of them connect the cortex with other centers and parts of the brain. In white matter there are accumulations of gray - basal ganglia. To the hemispheres of the brain are attached legs and thalamus. The boundary segment from the thalamuses of the intermediate section of the interlayer of white matter is called the inner capsule. The hemispheres are separated by a longitudinal slit. In each segment there are three surfaces - the lower, lateral and medial - and the same number of margins: the temporal, occipital and frontal.

Surface of a raincoat

In each segment, this part of the brain is divided into segments by means of deep furrows and cracks. Primary refers to the permanent formations of the organ. They are formed at the embryonic stage (in the fifth month). The largest slits are longitudinal (separates segments) and transverse (separates the cerebellum from the occipital lobes). Secondary and in particular - tertiary formations determine the individual relief of the segments (it is seen in the photo). The human brain develops not only in the intrauterine period. For example, secondary and tertiary furrows are formed up to 7-8 years after birth. The relief, which has a finite brain, the location of permanent formations and large convolutions in most people are similar. Each segment is divided into six parts: limbic, islet, temporal, occipital, parietal and frontal.

Lateral surface

The final brain in this area includes the Roland (central) furrow. With her help, the parietal and frontal lobes are divided. Also on the surface there is a sylvian (lateral) furrow. Through it, the parietal and frontal lobes are separated from the temporal lobes. As the anterior margin of the occipital region is a conditional line. It passes from the upper edge of the parietal-occipital furrow. The line is directed toward the lower end of the hemisphere. The islet (islet fraction) is covered by the temporal, parietal and frontal regions. It lies in the lateral furrow (in the depth). Near the corpus callosum, the limbic part is located along the medial side. It is separated from other areas by means of a waist furrow.

Brain: anatomy. Frontal lobe

It contains the following elements:

• The precentral groove. The same gyrus is located between it and the central depression.
• Frontal furrows (lower and upper). The first is divided into three zones: orbital (orbital), triangular (triangular), opercular (capillary). Between the depressions lie the frontal gyrus: the upper, lower and middle.
• Horizontal anterior furrow and ascending branch.
• Frontal medial gyrus. It is separated from the limbic waist furrow.
• Section of the cingulate gyrus.
• Glandular and olfactory furrows. They are on the underside of the frontal lobe. In the olfactory groove there are the same elements: the bulb, the triangle and the tract.
• Straight gyrus. It passes between the medial end of the hemisphere and the olfactory groove.

The anterior horn in the lateral ventricle corresponds to the frontal lobe.

Tasks of Cortical Zones

Considering the final brain, the structure and functions of this organ, it is necessary to dwell in more detail on the activity of the frontal lobes:

• The anterior central gyrus. Here there is a cortical core from the motor analyzer, or kinesthetic center. This zone receives a certain amount of afferent fibers from the side of the thalamus. They carry proprioceptive information from the joints and muscles. In this area, the descending path to the spinal cord and trunk begins. They provide the possibility of conscious regulation of movements. If the final brain is damaged in this zone, then paralysis of the opposite side of the body occurs.
• The posterior third is in the frontal middle gyrus. Here is the center of graphics (letters) and the associative zone of signs.
• The posterior third of the frontal lower gyrus. In this area is the speech center.
• The middle and anterior third of the middle, upper and partly lower frontal gyrus. In this area, the associative anterior cortical zone lies. It performs programming of various complex behavioral forms. The zone of the medial frontal gyrus and frontal pole is associated with the regulation of the emotionogenic areas included in the limbic system. This area refers to the control of the psycho-emotional background.
• The anterior part of the frontal middle gyrus. There is a zone of combined rotation of the eyes and head.

The dark share

It corresponds to the middle region of the lateral ventricle. The final brain in this area includes a postcentral gyrus and a furrow, parietal lobules - the upper and lower. Behind the parietal lobe is the anterior one. In the structure there is also an intertematic sulcus. In the lower region there are meanders - angular and marginal, as well as a segment of the paracentral lobule.

Tasks of cortical areas in the parietal lobe

Describing the final brain, the structure and functions of this structure, it is necessary to distinguish such centers as:

• Projection department of general sensitivity. This center is a cutaneous analyzer and is represented by the cortex of a postcentral gyrus.
• Projection department of the body scheme. It corresponds to the edge of the intra-suture groove.
• Association of "stereognosy." It is represented by the core of the analyzer (cutaneous) recognition of objects when feeling. This center corresponds to the cortex of the parietal upper lobe.
• Associative department of "praxia". This center performs tasks on the analysis of habitual purposeful movements. It corresponds to the crest of the marginal gyrus.
• The associative optical department of speech is a writing analyzer - the center of lexicon. This zone corresponds to the cortex of the angular gyrus.

Brain: anatomy. The temporal lobe

On its lateral side there are two furrows: the lower and upper ones. They, together with the lateral, limit the convolutions. On the lower surface of the temporal lobe there is no clear boundary separating it from the posterior part. Near the lingual gyrus is the occiputa-temporal. From the top it is limited by the collateral fissure of the limbic region, and laterally by the temporal occipital fissure. The proportion corresponds to the lower horn of the lateral ventricle.

The tasks of cortical zones in the temporal department

• In the middle section of the upper gyrus, on its upper side, is located the cortical part of the auditory analyzer. The posterior third of the gyrus includes the auditory zone of speech. When trauma of this area, the speaker's words are perceived as noise.
• The lower and middle area of the convolutions contains the cortical center of the vestibular analyzer. If the functions of the terminal brain are violated here, the ability to maintain balance on standing will be lost, the sensitivity of the vestibular apparatus will decrease.

Island

This share is in the lateral and is limited by a circular furrow. Presumably in this area, the functions of the brain are manifested in the analysis of taste and olfactory sensations. In addition, the problems of the region probably include auditory perception of speech and processing of somatosensory information.

Limbic share

This region is located on the medial surface of the hemispheres. It consists of the belt, para-hippocampal and dentate gyrus, isthmus. As one of the boundaries of the share is a furrow of the corpus callosum. She sinks to the deepening of the hippocampus. Under this furrow, in turn, there is a meander in the lower horn cavity of the lateral ventricle. Above the depression in the calloused body lies another border. This line - the waist furrow - separates the girdle gyrus, delimits the parietal and frontal lobes from the limbic. With the help of the isthmus the girdle gyrus becomes parahippocampal. The latter ends with a crochet.

Tasks of the Department

The para-hippocampal and girdle gyruses refer directly to the limbic system. The functions of the brain in this area are connected with the control of a complex of psychoemotional, behavioral and vegetative reactions to stimuli of the external environment. The para-hypocampal zone and the hook include the cortical region of the olfactory and taste analyzer. In this case, the hippocampus is associated with learning abilities, it determines the mechanisms of long-term and short-term memory.

Occipital region

On its lateral side is a transverse furrow. In the medial part there is a wedge. Behind it restricts the spur, and in front - the parietal-occipital furrow. Also on the medial site there is a linguistic gyrus. From above it is limited to the spurs, and below - to the collateral furrow. The occipital lobe corresponds to the posterior horn in the lateral ventricle.

The departments of the occipital region

In this zone, there are such centers as:

• Projective visual. This segment is located in the cortex, which limits the furrow groove.
• Associative visual. The center is located in the cortex of the dorsal region.

White matter

It is presented in the form of numerous fibers. They are divided into three groups:

• Projection . This category is represented by bundles of efferent and afferent fibers. Through them, there are connections between projection centers and basal, stem and spinal nuclei.
• Associative . These fibers provide the connection of cortical areas within the boundaries of one hemisphere. They are divided into short and long.
• Commissural . These elements connect the cortical zones of the opposite hemispheres. Comissural formations are: corpus callosum, posterior and anterior adhesion and spike of the arch.

Bark

Its main part is represented by the neocortex. This is the "new crust", which phylogenetic is the latest brain formation. The neocortex occupies about 95.9% of the surface. The rest of the brain is represented as:

• The old bark is the archiocotex. It is located in the region of the temporal lobe and is called the amon horn, or hippocampus.
• Ancient cortex - paleocortex. This formation occupies a site in the frontal lobe next to the olfactory bulbs.
• Mesocortex . These are small areas adjacent to the paleocortex.

Old and ancient cortex appear in vertebrates before others. These formations are distinguished by a comparatively primitive internal structure.