Structural elements of the brain table. The structure of the human brain. What does the human brain look like

Brain - the most important body a person who regulates and directs the main processes occurring in the body. The brain anatomically occupies the entire cranial cavity, it is protected from external influences and from electromagnetic radiation by strong bone tissues. Also above it are numerous shells that also perform a protective function.

According to medical literature, the brain is part of the central nervous system, interacting with internal organs, tissues, muscles and joints with the help of neurons that can send signals either to or from the brain. In this way, human life is coordinated, all the actions that people perform in everyday life are regulated by the brain.

1. oblong;
2. average;
3. posterior, including the cerebellum and pons;
4. intermediate;
5. finite.

Each of these 5 departments performs a strictly defined function. Despite this, all departments are tightly interconnected. There is also such a thing as a brain stem. It includes three sections at once: oblong, posterior and middle. The trunk is similar in content to the dorsal, this is due to the fact that the trunk of the head and spinal cord very strong anatomical relationship.

The brain stem is the oldest part of the main human organ. In the pre-evolutionary period, the main parts of the trunk (sections) were the only ones, but in the process of evolution two more sections were added to them.

Video

What is the carrier of consciousness - brain cells or electrical signals generated by them? Where do the consciousness and personality of a person come from and where do they go at the end of their journey? These questions concern many.

The human brain is one of the most mysterious organs human body. Scientists still cannot fully understand the mechanism of mental activity, the functioning of consciousness and subconsciousness.

Structure

• large hemispheres;
• brain stem;
• cerebellum.

• forebrain (large hemispheres);


• hindbrain (cerebellum, pons Varolii);


• medulla;


• midbrain;


• intermediate brain.

Next comes Pons- This is a roller of nerve transverse fibers and gray matter. The main artery that feeds the brain passes through it. It starts above the medulla oblongata and passes into the cerebellum.

Cerebellum consists of two small hemispheres connected by a "worm", as well as white matter and gray matter covering it. This department is connected by pairs of "legs" to the oblong bridge, the cerebellum and the midbrain.

midbrain consists of two visual hillocks, and two auditory (quadrigemina). Nerve fibers that connect the brain with the spinal cord depart from these tubercles.

Large hemispheres of the brain separated by a deep fissure with the corpus callosum inside, which connects these two sections of the brain. Each hemisphere has a frontal, temporal, parietal and occipital. The hemispheres are covered by the cerebral cortex, in which all thought processes take place.

In addition, there are three layers of the brain:

• Hard, which is the periosteum of the inner surface of the skull. This shell is concentrated a large number of pain receptors.


• Arachnoid, which is closely adjacent to the cerebral cortex, but does not line the gyrus. The space between it and the hard shell is filled with serous fluid, and the space between it and the cerebral cortex is filled with cerebrospinal fluid.


• Soft, consisting of a system blood vessels and connective tissue contacting with the entire surface of the substance of the brain, and feeding it.

Functions and tasks

Medulla contains nerve centers that ensure the normal functioning of protective reflexes - sneezing, coughing, blinking, vomiting. He also "rules" the respiratory and swallowing reflexes, salivation and secretion of gastric juice.

Pons responsible for normal movement eyeballs and coordination of the work of mimic muscles.

Cerebellum exercises control over the consistency and coordination of movement.

midbrain provides a regulatory function in relation to the acuity of hearing and clarity of vision. This part of the brain controls the expansion-constriction of the pupil, changes in the curvature of the lens of the eye, and is responsible for the muscle tone of the eye. It also contains the nerve centers of the orientation reflex in space.

• thalamus- a kind of "switch" that processes and forms sensations from information from temperature, pain, vibration, muscle, taste, tactile, auditory, olfactory receptors, one of the subcortical visual centers. Also this site responsible for changing the state of sleep and wakefulness in the body.


• Hypothalamus- this small area performs the most important task of controlling heart rate, thermoregulation of the body, blood pressure. It also "manages" the mechanisms of emotional regulation - it affects the endocrine system in order to develop the hormones necessary to overcome stressful situations. The hypothalamus regulates hunger, thirst and satiety. It is the center of pleasure and sexuality.


• Pituitary- this brain appendage produces growth hormones of puberty, development and functioning.


• Epithalamus- includes the pineal gland, which regulates daily biological rhythms, releasing hormones at night for normal and long falling asleep, and during the day - for a normal mode of wakefulness and activity. Directly with the regulation of sleep and wakefulness is associated with the control of the body's adaptation to lighting conditions. The pineal gland is able to pick up vibrations of light waves even through the cranium, and respond to them by releasing the necessary hormones. Also, this small part of the brain regulates the rate of metabolism in the body (metabolism).

Left cerebral hemisphere- exercises control over the speech functions of the body, the implementation of analytical activities, mathematical calculations. Here abstract thinking is formed, the movement of the left limbs is controlled.

Each of the hemispheres of the brain is divided into 4 lobes:

1. Frontal lobes- they can be compared with the navigational cabin of the ship. They ensure the maintenance of the vertical position of the human body. Also, this site is responsible for how active and inquisitive a person is, initiative and independent in making decisions.

In the frontal lobes, processes of critical self-evaluation take place. Any violations in the frontal lobes lead to the manifestation of inadequacy in behavior, senselessness of actions, apathy and sudden mood swings. Also, "logging" manages human behavior and control over it - the prevention of deviations, socially unacceptable actions.

In the left (dominant) lobe, control is exercised over human speech, ensuring abstract thinking.

2. Temporal lobes- this is a long-term storage. The left (dominant) share stores information about the specific names of objects, the links between them. The right lobe is responsible for visual memory and imagery.

Their important function is also speech recognition. The left lobe deciphers for consciousness the semantic load of the spoken words, and the right lobe provides an understanding of their intonational coloring and facial expressions, explaining the mood of the speaker and the degree of his goodwill towards us.

The temporal lobes also provide the perception of olfactory information.

3. Parietal lobes- participate in perception pain, feelings of cold, heat. The functions of the right and left lobes are different.

The left (dominant) share provides the processes of synthesizing information fragments, combining them into single system, allows a person to read and count. This share is responsible for the assimilation of a certain algorithm of movements leading to a specific result, the feeling of individual parts own body and a sense of its integrity, the definition of right and left sides.

The right (non-dominant) lobe transforms the entire set of information coming from the occipital lobes, forming a three-dimensional picture of the world, provides orientation in space, determining the distance between objects and to them.

4. Occipital lobes- processing visual information. perceive objects of the surrounding world as a set of stimuli that reflect light on the retina in different ways. The occipital lobes convert light signals into information about the color, movement and shape of objects that are understandable to the parietal lobes, which form three-dimensional images in our minds.

Brain diseases

Conventionally, they can be divided into:

• tumor;


• viral;


• vascular;


• neurodegenerative.

Symptoms may include: nausea,

human brain(encephalon, cerebrum) is an organ that not only controls all internal processes, but is also responsible for emotions, feelings, thoughts, memory, behavior. The structure and functions of the brain distinguish people from other representatives of the living world as more highly developed and complexly organized creatures, and determine the difference in capabilities.

The brain weighs about 1-2 kg, which is about 2% of the total human weight. Despite this, nerve cells consume about 50% of all glucose in the body, and 20% of the blood passes through the cerebral vessels. For a simplified understanding of the central nervous system, it is customary to distinguish parts.

Different authors describe the structure of the brain according to different criteria, there are many diagrams and tables. A single activity or the embryonic period is taken as the basis. The structure of the brain, as well as its function, still cause numerous theories and disputes.

Let's analyze the structure and properties of the brain (briefly)

Oblong (myelencephalon)

It is located below all, conditionally ends in front of the occipital foramen.
The medulla oblongata performs a variety of activities. With the help of reflexes of blinking, sneezing, coughing, vomiting, it implements a protective role. Here are important centers that control breathing and blood pressure. They maintain a stable and optimal composition of the blood, receiving information from receptors and transmitting it to the overlying divisions, and also helps to maintain body posture and coordination of movements.

It does all this thanks to the nuclei of the cranial nerves, the nuclei of balance (olive), nerve pathways (pyramidal, thin and wedge-shaped bundles) etc.

Pons

The bridge is in line with the medulla oblongata and midbrain. It contains the nuclei of the cochlear, facial, trigeminal and abducens nerves, the medial and lateral loop, corticospinal and corticobulbar reflex arcs. Its structure allows a person to eat, express his emotions with facial expressions, hear, feel with the skin of his face and lips. The bridge carries out these operations jointly with other structures.

Medium (Mesencephalon)

In the midbrain, a roof and legs are distinguished. The roof is responsible for hearing and vision, has nuclei and subcortical centers corresponding to them. The legs of the brain contain pathways. Divided into a tire and a base. The tire contains extrapyramidal pathways responsible for coordination and automatism. The base consists of paths connecting with other departments.

Cerebellum

The appearance of the cerebellum resembles a large brain. It also has left and right parts and between them is a "worm". The cerebellum is connected to all functional units. This connection is carried out thanks to the cerebellar legs.

With the help of nerve bundles, the cerebellum receives a copy of the data between the spinal cord and the cerebral cortex. It compares information about what is happening right now, and information about how it should be. After the correlation of errors, the cerebellum sends an alert to the motor centers. Thus, it corrects reflex, automatic and voluntary movements. Despite the neuronal connection with the gray matter of the cerebral hemispheres, actions cannot be controlled by consciousness.

Thanks to the cerebellum, a person can walk, write, type on a keyboard, play musical instruments, ride a bicycle. Receiving information from the muscles, tendons, vestibular apparatus, it regulates the balance, body position, smoothness of movements, postures, realizes the automatism of movements, muscle memory

Intermediate (diencephalon)

The diencephalon consists of the thalamencephalon and the hypothalamus hypothalamus.

Thalamencephalon, in turn, consists of:

Thalamus. He is a collector of all kinds of sensibility. Here, signals from all receptors of the body, except for the sense of smell, are combined, analyzed, switched. The thalamus is also responsible for emotional reaction, facial expressions, behavior on the received stimuli.

Epithalamus. This formation is otherwise called the pineal body. It regulates the flow of internal processes according to the natural rhythm of nature.

Metathalamus. Contains groups of cells responsible for hearing and vision.

Good to know: Basal nuclei (ganglia) of the brain

The hypothalamus is a neuroendocrine center. The vegetative system controls the vegetative part of the body's activity. There are various receptors that sense changes in blood parameters, the level of concentration is vital essential substances. The received information is processed by the central link. Allocate the center of thirst, hunger, fear, pleasure. Depending on the type of autonomic influence, the hypothalamus is divided into two parts. The anterior part controls parasympathy (relaxation of the vascular wall, slowing down of the heart, increased intestinal motility), the posterior part controls sympathy (increased rhythm, increased blood pressure, bronchial dilatation).
The hypothalamus is closely related to the pituitary gland. Together they carry out humoral regulation body activity. They secrete hormones that regulate the exchange of salts and water, the tone of the uterus, the implementation of childbirth and breastfeeding, synthesize hormones that regulate the work of other endocrine glands.

Final (telencephalon)

The telencephalon has a structure similar to the cerebellum - it consists of two cerebral hemispheres, connecting them to the corpus callosum, covered with a cortex cerebri. This is a special multilayer tissue in which a variety of nerve cells are distributed. For a larger area, the cortex forms convolutions and tubercles. The architecture of the convolutions of each person is individual. But everyone has the most pronounced and deep convolutions. They share everything. Each share fulfills a certain possibility.

In addition to such a division, scientists have compiled entire maps with analyzer fields. The most famous motor and sensitive homunculus.
Fields are divided not only by function, but also by the level of perception of information. Primary receive information from the senses. A person feels taste, temperature, sees color, shape, hears sound. Secondary generalize data, create an image. Suppose a person sees a yellow round object, feels roughness, feels a characteristic smell, a sour taste. Already having experience, a person knows that this object is called a lemon. Thanks to these fields, people distinguish objects from each other. Tertiary fields help to draw conclusions, and based on this, take actions, for example, use tools.

Good to know: The gray matter of the brain, its structure, functions and properties

In addition to the analyzer fields, associative zones are distinguished. These sites provide a connection between different areas and fields of the cortex. Fortunately, a person can perform complex actions, such as speech, reading, writing, thinking, memory and others.

In the telencephalon, it is customary to isolate the limbic system. This is an association of different structures that receive signals about a change in the functioning of an organ. According to the received signal, a change in the blood count, the limbic system corrects the activity of another system. This is how the work of the affected organ is compensated by healthy ones, adaptation to stressful situations.
Having studied the brain, the structure and role of the cerebral hemispheres, we conclude that it maintains constant optimal values ​​of parameters, controls unconditioned innate reflexes and conditioned ones acquired in the process of life experience. And most importantly, the gray matter materializes the psyche, the mind of a person, his intellect. The functions of the large brain distinguish a person from an animal.

The structure of the brain is logical and consistent

The structure of the human brain is of great interest. Despite the development of techniques and methods of examination, scientists do not stop discovering new brain structures. Simplified for understanding, the analysis of the organization only slightly reveals the numerous interconnections and mutual influences of the parts of the brain. Each structure makes its own specific contribution to the function of the brain. The structure of the brain is logical and consistent.

Coordinated activity of all functional units contributes to the maximum adaptation of Homo sapiens to natural circumstances, keeps the optimal balance of the parameters of all processes inside the body. The phylogenetically ancient parts of the brain control the adequate functioning of internal systems, perform innate reflexes necessary for survival. New areas in the evolutionary concept realize the mental sphere of a person, behavior in society, self-consciousness. Violation of the functioning of any zone leads to disability. By correlating the structure of the brain and the violation of its function with clinical symptoms, localization can be determined.

Independent work of students

Topic "Local systems of the brain and their functional organization"

Exercise 1. Using the content of the text "The brain, its structure and functions", fill in the table:

Table 1.

The structure and functions of the brain

Task 2. Using a dictionary on the topic "Local systems of the brain and their functional organization", fill in the table:

Table 2.

Local brain systems and their functional organization

The brain, its structure and functions The structure of the brain

Spinal cord, located in the spinal column, regulates the simplest automated muscle-motor reactions, it passes into the medulla oblongata of the brain.

Brain- the anterior part of the central nervous system of vertebrates, located in the cranial cavity; the main regulator of all vital functions of the body and the material substrate of its higher nervous activity. The brain is most highly developed in humans due to an increase in mass and complication of the structure of the cerebral cortex.

Brain

Outside, the brain is covered with connective tissue membranes, in which blood vessels pass. The cavities of the brain - the ventricles - are a continuation of the spinal canal and are filled with a liquid - cerebrospinal fluid. The brain, like the spinal cord, has white and gray matter. pathways that connect the brain with the spinal cord white substance. They also connect different parts of the brain. Gray matter The brain is located in the form of separate clusters - nuclei - inside the white matter. In addition, gray matter covers the hemispheres of the brain and cerebellum, forms the cerebral cortex and the cerebellar cortex. 12 pairs of cranial nerves leave the brain.

Table 1. Parts of the brain

The medulla oblongata, pons and midbrain form brain stem.

Medulla It is a continuation of the spinal cord and connects it with the overlying parts of the brain. The anatomical position of the medulla oblongata determines its conductive function. All ascending and descending paths pass through the medulla oblongata, connecting the centers of the brain and spinal cord. The medulla oblongata regulates various life-support processes in the body - heart rate, breathing, blood pressure; coughing, blinking, tearing, vomiting, sucking, swallowing, etc.

The central part of the medulla oblongata is reticular formation(from lat. reticulum - mesh) - a diffuse network of highly branching interneurons. It extends to the thalamus. The reticular formation of the brain stem performs integrative-coordinating functions. It is involved in the regulation of excitability and maintaining the tone of all parts of the central nervous system, including the cerebral cortex. The activity of the reticular formation itself is supported by impulses coming from ascending sensory pathways. In turn, the cerebral cortex has a downward inhibitory effect on the reticular formation of the brainstem. The reticular formation also receives descending influences from the cerebellum, subcortical nuclei, and the limbic system. Reticular neurons are involved in the regulation of the cardiovascular system (in maintaining blood pressure, in the regulation of respiration.

Bridge(pons varolii) acts as a switching center between brain regions and between the spinal cord and the brain and therefore plays an important role in integration. Through the nuclei of the bridge, the cerebral cortex influences the cerebellum - this is the main channel of their communication. The pons contains the respiratory center, which, together with respiratory center medulla oblongata regulates breathing. The reticular formation of the bridge (together with the medulla oblongata) is involved in the regulation of muscle tone, maintaining posture, and body orientation in space. Here are the vestibular nuclei. In the reticular formation of the bridge there are centers that control rapid eye movements - saccades.

Constance Varolius(1543-1575) - Italian anatomist, professor, life physician of Pope Gregory XIII. Performed a large number of studies in the field of anatomy of the brain and cranial nerves.

Cerebellum consists of a worm and two hemispheres, the surface of which is formed by a strongly folded multilayer cortex formed by several types of neurons (Purkinje cells, stellate, basket, etc.). In the depths of the hemispheres are clusters of neurons - nuclei. From the nuclei of the cerebellum, part of the fibers goes to the motor nuclei of the brain stem, the other part goes to the thalamus (interbrain), and through it to the cerebral cortex. The cerebellum regulates motor acts. If its normal operation is disturbed, the ability to accurately coordinated movements and maintain balance is lost. The functions of the cerebellar vermis are associated with the vestibular apparatus. The cerebellum receives information from other sensory systems: visual, auditory, somatosensory.

Purkinje Jan Evangelista(1787-1869) - Czech naturalist, professor, corresponding member. Petersburg Academy of Sciences, etc., one of the founders of the theory of the cellular structure of plants and animals.

midbrain enters the brainstem, it connects the hindbrain with the anterior, through it all the nerve paths from the senses to the cerebral hemispheres pass. The midbrain includes the quadrigemina and the cerebral peduncles. The midbrain regulates the functioning of the sense organs. The manifestation of innate orienting reflexes (listening, peering). The structures of the midbrain are involved in the regulation of movements and muscle tone, the regulation of the acts of chewing, swallowing, their sequence, and provide accurate hand movements, for example, when writing. The nuclei of the anterior tubercles of the quadrigemina are primary visual subcortical centers, the nuclei of the posterior tubercles - auditory. The neurons of the anterior colliculus respond to the change of light and darkness; this part of the brain is associated with the turn of the head in the direction of visual and auditory stimuli.

In the midbrain there is a formation continuing from the medulla oblongata - reticular formation. Impulses from the sense organs, as it were, charge this formation, and it has an activating (tonifying) effect on the activity of the brain. The reticular formation of the midbrain plays an important role in the regulation of wakefulness and the state of involuntary attention.

diencephalon- located above the midbrain. Includes thalamus(optical tubercle), hypothalamus(sub-tubercular region), supratuberous region, limbic system and controls different types sensitivity (somatic, pain, vision, hearing), complex vital (vital) reactions, nutrition, protection, reproduction, mental reactions (sleep, memory), homeostasis maintenance. Two glands are structurally and functionally connected with the diencephalon internal secretion- pituitary and pineal.

thalamus- a complex polyfunctional formation, including specific nucleus, where afferentation is switched from the sense organs to the corresponding areas of the cerebral cortex, associative nucleus where this afferentation interacts and is partly processed, and non-specific nuclei through which impulse flows from the reticular formation pass. These groups of nuclei are interconnected and a system of bilateral connections with the cerebral hemispheres. The thalamus is associated with the reticular formation of the brain stem, the hypothalamus, and the cerebral cortex. The structure and numerous connections of the thalamus ensure its participation in the organization of complex motor reactions, such as sucking, chewing, swallowing, laughing, etc.

Hypothalamus- the center of regulation of the activity of internal organs, the endocrine system, metabolism, body temperature, the wake-sleep cycle. The hypothalamus, through the pituitary gland, controls the work of the endocrine glands and, due to this, is involved in the regulation of emotions and the formation of motivations.

Subcortical formations, regulating innate unconditional reflex activity, are the area of ​​those processes that are subjectively felt in the form of emotions.

The structures of the human brain contain "experience" accumulated in the process of evolutionary development.

telencephalon: basal ganglia (nucleus) and cerebral cortex.

Basal ganglia- a complex of subcortical nuclei, immersed in the white matter of the cerebral hemispheres and surrounded by fibers connecting them with the cerebral cortex.

Particularly developed in humans cerebral cortex- an organ of higher mental functions. The cerebral cortex is a layer of gray matter formed by clusters of neurons. In the cortex of each of the hemispheres, 4 lobes or regions are distinguished: frontal, parietal, temporal and occipital. They are divided into smaller fields that differ from each other in their structure and purpose. In accordance with the most common classification proposed by K. Brodman, the cerebral cortex is divided into 11 regions and 52 fields.

Different fields of the cortex are characterized by features of the neurochemical composition. So, norepinephrine is found everywhere in the neurons of the cortex, but more of it in the somatosensory cortex. It plays a special role in the perception of tactile information. Substances that increase the accumulation of noradrenaline in neurons (for example, cocaine) can cause hallucinations. Another substance - dopamine - is found in large quantities in the anterior sections of the frontal lobe, in the prefrontal field.

AT frontal lobe zone is located oral speech, centers of emotions, memory; the center of logical thinking, coordinates the motor mechanisms of speech.

AT parietal- centers of skin-muscle perception, spatial orientation, memory associated with speech and learning, the center of somatic sensitivity.

AT temporal- centers of auditory perception, speech control, spatial analysis, memory center.

AT occipital centers of visual perception.

Functional areas of the cortex. A feature of their organization is that the signals from the receptors are projected not to one neuron, but to a group of neurons. As a result, the signal is focused not only at one point (in one field), but spreads over a certain distance and captures a set of neurons. This provides signal analysis and the possibility of its transmission to other brain structures. From their primary sensory areas, the impulses propagate to the associative and motor areas.

Sensory areas of the cortex receive specific sensory information: visual (occipital), auditory (temporal), motasensory and gustatory (parietal). The somatosensory zone of the cortex - the area of ​​\u200b\u200bmuscle and skin sensitivity - is located in the posterior central gyrus, behind the central sulcus. When it is irritated, there is a sensation of touch, tingling, numbness. The largest area is occupied by the sensory area of ​​the hand, and then the vocal apparatus and face, the smallest dimensions are the sensory areas of the trunk, thigh, lower leg, i.e. areas with lower sensitivity.

Penfield scheme. Wilber Graves Penfield (1891-1976, Nobel Prize, Canadian neurologist and neurosurgeon) together with I. Ramussen created the famous drawings: “Sensitive Homonculus” and “Motor Homonculus” - the cortical center of general sensitivity and the motor area of ​​the cerebral cortex.

"Homunculus" lat. - a little man, according to the ideas of medieval alchemists - a kind of creature that can be obtained artificially (in a flask).

 Sensory visual cortex located in occipital cortical areas.

 Sensory auditory zone is in temporal areas.

 Zone taste sensations located in parietal areas.

 Zone olfactory sensitivity located in old bark.

Motor(motor, afferent) zones are located in the anterior central gyrus of the frontal lobe.

Association zones receive impulses from all areas of the cortex. The associative cortex is the limbic cortex. The limbic system of the brain integrates three types of information: 1) about the work of internal organs, 2) from the sensory, motor and associative areas of the cortex, 3) from olfactory receptors.

The main structure of the cerebral hemispheres is the new cortex, which covers their surface. In the depths of the cerebral hemispheres is the old cortex - the hippocampus and various large nuclear formations (basal ganglia) associated with the implementation of mental functions. There is also an ancient cortex, which has only one layer of cells, not completely separated from the subcortical structures. Area of ​​new, old and ancient crust: ~ 96%, ~ 3%, ~ 1%.

The brain is part of the central nervous system, the main regulator of all vital functions of the body. As a result of his defeat, severe diseases occur. The brain contains 25 billion neurons that make up the cerebral gray matter. The brain is covered by three membranes - hard, soft and arachnoid located between them, through the channels of which cerebrospinal fluid (CSF) circulates. Liquor is a kind of hydraulic shock absorber. The brain of an adult male weighs an average of 1375 g, women - 1245 g. However, this does not mean that in men it is better developed. Sometimes the weight of the brain can reach 1800 g.

Structure

The brain consists of 5 main sections: the final, diencephalon, middle, hindbrain and medulla oblongata. The telencephalon makes up 80% of the total mass of the brain. It stretched from the frontal bone to the occipital. The telencephalon consists of two hemispheres, in which there are many furrows and convolutions. It is divided into several lobes (frontal, parietal, temporal and occipital). Distinguish between the subcortex and the cerebral cortex. The subcortex consists of subcortical nuclei that regulate various body functions. The brain is located in three cranial fossae. The large hemispheres occupy the anterior and middle fossa, and the posterior fossa - the cerebellum, under which the medulla oblongata is located.

Functions

The functions of different parts of the brain are different.

telencephalon

There are about 10 billion neurons in the gray cortex. They make up only a 3 mm layer, but their nerve fibers are branched like a network. Each neuron can have up to 10,000 contacts with other neurons. Part of the nerve fibers through the corpus callosum of the large brain connects the right and left hemisphere. Neurons make up the gray matter and fibers make up the white matter. Within the cerebral hemispheres, between frontal lobes and diencephalon, accumulations of gray matter are located. These are the basal ganglia. Ganglia are clusters of neurons that transmit information.

diencephalon

The diencephalon is divided into ventral (hypothalamus) and dorsal (thalamus, metathalamus, epithalamus) parts. The thalamus is the mediator in which all stimuli received from the outside world converge and are directed to the cerebral hemispheres in such a way that the body can adequately adapt to a constantly changing environment. The hypothalamus is the main subcortical center for the regulation of the autonomic functions of the body.

midbrain

It extends from the anterior edge of the pons to the optic tracts and papillary bodies. It consists of the legs of the large brain and the quadrigemina. All ascending paths to the cerebral cortex and cerebellum and descending ones, carrying impulses to the medulla oblongata and spinal cord, pass through the midbrain. It is important for processing nerve impulses from visual and auditory receptors.

Cerebellum and bridge

The cerebellum is located in the occipital region behind the medulla oblongata and the pons. It consists of two hemispheres and a worm between them. The surface of the cerebellum is dotted with furrows. The cerebellum is involved in the coordination of complex motor acts.

Ventricles of the brain

The lateral ventricles are located in the forebrain hemispheres. The third ventricle is located between the visual tubercles and is connected to the fourth ventricle, which communicates with the subarachnoid space. Liquor, located in the ventricles, circulates in the arachnoid mater.

Large (terminal) brain functions

Thanks to the work of the brain, a person can think, feel, hear, see, touch, move. The large (final) brain controls all vital processes occurring in the human body, and is also the "receptacle" of all our intellectual abilities. From the world of animals, a person, first of all, is distinguished by developed speech and the ability to abstract thinking, i.e. the ability to think in moral or logical categories. Only in the human mind can various ideas arise, for example, political, philosophical, theological, artistic, technical, creative.

In addition, the brain regulates and coordinates the work of all human muscles (both those that a person can control by willpower and those that do not depend on the will of a person, for example, the heart muscle). Muscles receive a series of impulses from the central nervous system, to which the muscles respond with a contraction of a certain strength and duration. Impulses enter the brain from various sense organs, causing the necessary reactions, for example, turning the head in the direction from which the noise is heard.

The left brain hemisphere controls the right half of the body, and the right hemisphere controls the left. The two hemispheres complement each other.

The brain resembles a walnut; three large sections are distinguished in it - the trunk, subcortical section and the cerebral cortex. The total surface of the cortex increases due to numerous furrows, which divide the entire surface of the hemisphere into convex convolutions and lobes. Three main sulci - central, lateral and parietal-occipital - divide each hemisphere into four lobes: frontal, parietal, occipital and temporal. Individual areas of the cerebral cortex have different functional value. Impulses from receptor formations enter the cerebral cortex. Each peripheral receptor apparatus in the cortex corresponds to an area called the cortical nucleus of the analyzer. An analyzer is an anatomical and physiological formation that provides the perception and analysis of information about phenomena occurring in the environment and (or) inside the human body, and forms sensations specific to a particular analyzer (for example, pain, visual, auditory analyzer). The areas of the cortex where the cortical nuclei of the analyzers are located are called the sensory zones of the cerebral cortex. The motor zone of the cerebral cortex interacts with the sensory zones, and when it is stimulated, movement occurs. This can be shown on simple example: when a candle flame approaches, pain and heat receptors of the fingers begin to send signals, then the neurons of the corresponding analyzer identify these signals as pain caused by a burn, and the muscles are “ordered” to withdraw their hand.

Association zones

Associative zones are functional zones of the cerebral cortex. They connect incoming sensory information with previously received and stored in memory, and also compare information received from different receptors. Sensory signals are comprehended, interpreted and, if necessary, transmitted to the motor area associated with it. Thus, associative zones are involved in the processes of thinking, memorization and learning.

Lobes of the telencephalon

The telencephalon is divided into the frontal, occipital, temporal and parietal lobes. In the frontal lobe there are zones of intellect, the ability to concentrate and motor zones; in the temporal - auditory zones, in the parietal - zones of taste, touch, spatial orientation, and in the occipital - visual zones.

Speech zone

Extensive damage to the left temporal lobe, such as from severe head trauma and various diseases, as well as after a stroke, are usually accompanied by sensory and motor speech disorders.

The telencephalon is the youngest and most developed part of the brain, which determines the ability of a person to think, feel, speak, analyze, and also controls all the processes occurring in the body. The functions of other parts of the brain primarily include the control and transmission of impulses, many vital important functions- they regulate hormone metabolism, metabolism, reflexes, etc.

The brain needs oxygen to function properly. For example, if during cardiac arrest or injury carotid artery cerebral circulation is disturbed, then after a few seconds the person loses consciousness, and after 2 minutes the brain cells begin to die.

Functions of the diencephalon

The visual tubercle (thalamus) and hypothalamus (hypothalamus) are parts of the diencephalon. Impulses from all receptors of the body enter the nuclei of the thalamus. The received information in the thalamus is processed and sent to the cerebral hemispheres. The thalamus connects to the cerebellum and the so-called limbic system. The hypothalamus regulates the autonomic functions of the body. The influence of the hypothalamus is carried out through nervous system and endocrine glands. The hypothalamus is also involved in the regulation of the functions of many endocrine glands and metabolism, as well as in the regulation of body temperature and the activity of the cardiovascular and digestive systems.

limbic system

The limbic system plays an important role in shaping human emotional behavior. The limbic system includes nerve formations located on the median side of the telencephalon. This area has not yet been fully explored. It is assumed that the limbic system and the hypothalamus that it controls are responsible for many of our feelings and desires, for example, thirst and hunger, fear, aggressiveness, and sexual desire arise under their influence.

Functions of the brain stem

The brain stem is a phylogenetically ancient part of the brain, consisting of the midbrain, hindbrain, and medulla oblongata. In the midbrain there are primary visual and auditory centers. With their participation, orienting reflexes to light and sound are carried out. In the medulla oblongata are centers for the regulation of respiration, cardiovascular activity, the functions of the digestive organs, and metabolism. The medulla oblongata is involved in the implementation of such reflex acts as chewing, sucking, sneezing, swallowing, vomiting.

Functions of the cerebellum

The cerebellum controls body movements. Impulses come to the cerebellum from all receptors that are irritated during body movements. The function of the cerebellum may be impaired when taking alcohol or other substances, causing dizziness. Therefore, under the influence of intoxication, people are not able to coordinate their movements normally. AT last years there is more and more evidence that the cerebellum is also important in human cognitive activity.

cranial nerves

In addition to the spinal cord, twelve cranial nerves are also very important: I and II pairs - olfactory and optic nerve; III, IV VI pairs - oculomotor nerves; V pair - trigeminal nerve - innervates the masticatory muscles; VII- facial nerve- innervates facial muscles, also contains secretory fibers to the lacrimal and salivary glands; VIII pair - vestibulocochlear nerve - connects the organs of hearing, balance and gravity; IX pair - glossopharyngeal nerve- innervates the pharynx, its muscles, parotid gland, taste buds of the tongue; X pair - the vagus nerve - is divided into a number of branches that innervate the lungs, heart, intestines, regulate their functions; XI pair - accessory nerve - innervates the muscles of the shoulder girdle. As a result of the fusion of the spinal nerves, the XII pair is formed - the hypoglossal nerve - innervates the muscles of the tongue and the hypoglossal apparatus.