The nervous system as a whole consists of. What is the nervous system? The activity of the nervous system, condition and protection

Subject. Structure and functions nervous system human

1 What is the nervous system

2 Central nervous system

Brain

Spinal cord

CNS

3 Autonomic nervous system

4 Development of the nervous system in ontogeny. Characteristics of the three-bubble and five-bubble stages of brain formation

What is the nervous system

Nervous system is a system that regulates the activity of all human organs and systems. This system causes:

1) the functional unity of all human organs and systems;

2) the connection of the whole organism with the environment.

Nervous system controls the activity of various organs, systems and apparatuses that make up the body. It regulates the functions of movement, digestion, respiration, blood supply, metabolic processes, etc. The nervous system establishes the relationship of the body with external environment unites all parts of the body into a single whole.

The nervous system according to the topographic principle is divided into central and peripheral ( rice. one).

central nervous system(CNS) includes head and spinal cord.

To peripheral part of the nervoussystems include spinal and cranial nerves with their roots and branches, nerve plexuses, nerve nodes, nerve endings.

In addition, the nervous system containstwo special parts : somatic (animal) and vegetative (autonomous).

somatic nervous system innervates mainly the organs of the soma (body): striated (skeletal) muscles (face, trunk, limbs), skin and some internal organs (tongue, larynx, pharynx). The somatic nervous system primarily performs the functions of connecting the body with the external environment, providing sensitivity and movement, causing contraction of the skeletal muscles. Since the functions of movement and feeling are characteristic of animals and distinguish them from plants, this part of the nervous system is calledanimal(animal). The actions of the somatic nervous system are controlled by human consciousness.

autonomic nervous system innervates the viscera, glands, smooth muscles of organs and skin, blood vessels and the heart, regulates metabolic processes in tissues. The autonomic nervous system influences the processes of the so-called plant life, common to animals and plants(metabolism, respiration, excretion, etc.), which is why its name comes from ( vegetative- vegetable).

Both systems are closely related, but the autonomic nervous system has some degree of autonomy and does not depend on our will, as a result of which it is also called autonomic nervous system.

She is being divided into two parts sympathetic and parasympathetic. The allocation of these departments is based both on the anatomical principle (differences in the location of the centers and the structure of the peripheral part of the sympathetic and parasympathetic nervous system), and on functional differences.

Excitation of the sympathetic nervous system contributes to the intensive activity of the body; excitation of the parasympathetic On the contrary, it helps to restore the resources expended by the body.

The sympathetic and parasympathetic systems have opposite influence on many organs, being functional antagonists. Yes, under influence of impulses coming along the sympathetic nerves, heart contractions become more frequent and intensified, blood pressure in the arteries rises, glycogen is broken down in the liver and muscles, blood glucose increases, pupils dilate, the sensitivity of the sense organs and the efficiency of the central nervous system increase, the bronchi narrow, contractions of the stomach and intestines are inhibited, secretion decreases gastric juice and pancreatic juice, the bladder relaxes and its emptying is delayed. Under the influence of impulses coming through the parasympathetic nerves, heart contractions slow down and weaken, blood pressure decreases, blood glucose decreases, contractions of the stomach and intestines are stimulated, secretion of gastric juice and pancreatic juice increases, etc.

central nervous system

Central nervous system (CNS)- the main part of the nervous system of animals and humans, made up of an accumulation nerve cells(neurons) and their processes.

central nervous system consists of the brain and spinal cord and their protective membranes.

The outermost is dura mater , below it is located arachnoid (arachnoid ), and then pia mater fused to the surface of the brain. Between the soft and arachnoid membranes is subarachnoid (subarachnoid) space , containing cerebrospinal (cerebrospinal) fluid, in which both the brain and spinal cord literally float. The action of the buoyancy force of the fluid leads to the fact that, for example, the adult brain, which has an average mass of 1500 g, actually weighs 50–100 g inside the skull. The meninges and cerebrospinal fluid also play the role of shock absorbers, softening all kinds of shocks and shocks that experiences the body and which could cause damage to the nervous system.

CNS formed from gray and white matter .

Gray matter make up cell bodies, dendrites and unmyelinated axons, organized into complexes that include countless synapses and serve as information processing centers for many of the functions of the nervous system.

white matter consists of myelinated and unmyelinated axons that act as conductors that transmit impulses from one center to another. The gray and white matter also contain glial cells.

CNS neurons form many circuits that perform two main functions: provide reflex activity, as well as complex information processing in higher brain centers. These higher centers, such as the visual cortex (visual cortex), receive incoming information, process it, and transmit a response signal along the axons.

The result of the activity of the nervous system- this or that activity, which is based on the contraction or relaxation of muscles or the secretion or cessation of secretion of glands. It is with the work of muscles and glands that any way of our self-expression is connected. Incoming sensory information is processed by passing through a sequence of centers connected by long axons, which form specific pathways, such as pain, visual, auditory. sensitive (ascending) pathways go in an upward direction to the centers of the brain. Motor (descending)) pathways connect the brain with motor neurons of the cranial and spinal nerves. Pathways are usually organized in such a way that information (for example, pain or tactile) from the right side of the body goes to the left side of the brain and vice versa. This rule also applies to descending motor pathways: the right half of the brain controls the movements of the left half of the body, and the left half controls the right. There are a few exceptions to this general rule, however.

Brain

consists of three main structures: the cerebral hemispheres, the cerebellum and the trunk.

Large hemispheres - the most large part brain - contain higher nerve centers that form the basis of consciousness, intellect, personality, speech, understanding. In each of the large hemispheres, the following formations are distinguished: isolated accumulations (nuclei) of gray matter lying in the depths, which contain many important centers; above them large array white matter; covering the hemispheres from the outside, a thick layer of gray matter with numerous convolutions, constituting the cerebral cortex.

Cerebellum also consists of a deep gray matter, an intermediate array of white matter and an outer thick layer of gray matter, forming many convolutions. The cerebellum provides mainly coordination of movements.

Trunk The brain is formed by a mass of gray and white matter, not divided into layers. The trunk is closely connected with the cerebral hemispheres, cerebellum and spinal cord and contains numerous centers of sensory and motor pathways. The first two pairs of cranial nerves depart from the cerebral hemispheres, while the remaining ten pairs from the trunk. The trunk regulates such vital important features like breathing and circulation.

Scientists have calculated that the brain of a man is heavier than the brain of a woman by an average of 100 gm. They explain this by the fact that most men, in their own way, physical parameters many more women, i.e. all parts of the body of a man more parts woman's body. The brain actively begins to grow even when the child is still in the womb. The brain reaches its "real" size only when a person reaches the age of twenty. At the very end of a person's life, his brain becomes a little lighter.

There are five main divisions in the brain:

1) telencephalon;

2) diencephalon;

3) midbrain;

4) hindbrain;

5) medulla oblongata.

If a person has suffered a traumatic brain injury, then this always negatively affects both his central nervous system and his mental state.

The "drawing" of the brain is very complex. The complexity of this "pattern" is predetermined by the fact that furrows and ridges go along the hemispheres, which form a kind of "gyrus". Despite the fact that this "drawing" is strictly individual, there are several common furrows. Thanks to these common furrows, biologists and anatomists have identified 5 lobes of the hemispheres:

1) frontal lobe;

2) parietal lobe;

3) occipital lobe;

4) temporal lobe;

5) hidden share.

Despite the fact that hundreds of works have been written on the study of the functions of the brain, its nature has not been fully elucidated. One of the most important mysteries that the brain “guesses” is vision. Rather, how and with what help we see. Many mistakenly assume that vision is the prerogative of the eyes. This is not true. Scientists are more inclined to believe that the eyes simply perceive the signals that our environment sends us. Eyes pass them on "by authority". The brain, having received this signal, builds a picture, i.e. we see what our brain “shows” to us. Similarly, the issue with hearing should be resolved: it is not the ears that hear. Rather, they also receive certain signals that the environment sends us.

Spinal cord.

The spinal cord looks like a cord, it is somewhat flattened from front to back. Its size in an adult is approximately 41 to 45 cm, and its weight is about 30 gm. It is "surrounded" by the meninges and is located in the brain canal. Throughout its length, the thickness of the spinal cord is the same. But it has only two thickenings:

1) cervical thickening;

2) lumbar thickening.

It is in these thickenings that the so-called innervation nerves of the upper and lower extremities are formed. Dorsal brainis divided into several departments:

1) cervical;

2) thoracic region;

3) lumbar;

4) sacral department.

Located inside the spinal column and protected by its bone tissue, the spinal cord has a cylindrical shape and is covered with three membranes. On a transverse section, the gray matter has the shape of the letter H or a butterfly. Gray matter is surrounded by white matter. The sensory fibers of the spinal nerves end in the dorsal (posterior) sections of the gray matter - the posterior horns (at the ends of H facing the back). body motor neurons spinal nerves are located in the ventral (anterior) sections of the gray matter - the anterior horns (at the ends of H, remote from the back). In the white matter, there are ascending sensory pathways ending in the gray matter of the spinal cord, and descending motor pathways coming from the gray matter. In addition, many fibers in the white matter connect the different parts of the gray matter of the spinal cord.

Main and specific CNS function- the implementation of simple and complex highly differentiated reflective reactions, called reflexes. In higher animals and humans, the lower and middle sections of the central nervous system - the spinal cord, medulla oblongata, midbrain, diencephalon and cerebellum - regulate the activity of individual organs and systems of a highly developed organism, communicate and interact between them, ensure the unity of the organism and the integrity of its activity. The highest department of the central nervous system - the cerebral cortex and the nearest subcortical formations - mainly regulates the connection and relationship of the body as a whole with the environment.

The main features of the structure and function CNS

connected with all organs and tissues through the peripheral nervous system, which in vertebrates includes cranial nerves from the brain, and spinal nerves- from the spinal cord, intervertebral nerve nodes, as well as the peripheral part of the autonomic nervous system - nerve nodes, with nerve fibers approaching them (preganglionic) and departing from them (postganglionic) nerve fibers.

Sensory, or afferent, nervous adductor fibers carry excitation to the central nervous system from peripheral receptors; by diverting efferent (motor and autonomic) nerve fibers excitation from the central nervous system is sent to the cells of the executive working apparatus (muscles, glands, blood vessels, etc.). In all parts of the CNS there are afferent neurons that perceive stimuli coming from the periphery, and efferent neurons that send nerve impulses to the periphery to various executive organs.

Afferent and efferent cells with their processes can contact each other and make up two-neuron reflex arc, carrying out elementary reflexes (for example, tendon reflexes of the spinal cord). But, as a rule, interneurons, or interneurons, are located in the reflex arc between the afferent and efferent neurons. Communication between different parts of the central nervous system is also carried out with the help of many processes of afferent, efferent and intercalary neurons of these departments, forming intracentral short and long pathways. The CNS also includes neuroglial cells, which perform a supporting function in it, and also participate in the metabolism of nerve cells.

The brain and spinal cord are covered with membranes:

1) dura mater;

2) arachnoid;

3) soft shell.

Hard shell. The hard shell covers the outside of the spinal cord. In its shape, it most of all resembles a bag. It should be said that the outer hard shell of the brain is the periosteum of the bones of the skull.

Arachnoid. The arachnoid is a substance that is almost closely adjacent to the hard shell of the spinal cord. The arachnoid membrane of both the spinal cord and the brain does not contain any blood vessels.

Soft shell. The pia mater of the spinal cord and brain contains nerves and blood vessels, which, in fact, feed both brains.

autonomic nervous system

autonomic nervous system It is one of the parts of our nervous system. The autonomic nervous system is responsible for: the activity of the internal organs, the activity of the endocrine and external secretion glands, the activity of the blood and lymphatic vessels, and also, to some extent, the muscles.

The autonomic nervous system is divided into two sections:

1) sympathetic section;

2) parasympathetic section.

Sympathetic nervous system dilates the pupil, it also causes an increase in heart rate, an increase in blood pressure, expands the small bronchi, etc. This nervous system is carried out by sympathetic spinal centers. It is from these centers that peripheral sympathetic fibers begin, which are located in the lateral horns of the spinal cord.

parasympathetic nervous system is responsible for the activity of the bladder, genitals, rectum, and it also “irritates” a number of other nerves (for example, glossopharyngeal, oculomotor nerve). Such a "diverse" activity of the parasympathetic nervous system is explained by the fact that its nerve centers are located both in the sacral spinal cord and in the brain stem. Now it becomes clear that those nerve centers that are located in the sacral spinal cord control the activity of organs located in the small pelvis; nerve centers located in the brain stem regulate the activity of other organs through a number of special nerves.

How is the control over the activity of the sympathetic and parasympathetic nervous system carried out? Control over the activity of these sections of the nervous system is carried out by special autonomic apparatus, which are located in the brain.

Diseases of the autonomic nervous system. The causes of diseases of the autonomic nervous system are as follows: a person does not tolerate hot weather or, conversely, feels uncomfortable in winter. A symptom may be that a person, when excited, quickly begins to blush or turn pale, his pulse quickens, he begins to sweat a lot.

It should be noted that diseases of the autonomic nervous system occur in people from birth. Many believe that if a person gets excited and blushes, then he is simply too modest and shy. Few people would think that this person has some kind of autonomic nervous system disease.

Also, these diseases can be acquired. For example, due to a head injury, chronic poisoning with mercury, arsenic, due to a dangerous infectious disease. They can also occur when a person is overworked, with a lack of vitamins, with strong mental disorders and experiences. Also, diseases of the autonomic nervous system can be the result of non-compliance with safety regulations at work with dangerous working conditions.

The regulatory activity of the autonomic nervous system may be impaired. Diseases can "mask" as other diseases. For example, when sick solar plexus there may be bloating, poor appetite; with a disease of the cervical or thoracic nodes of the sympathetic trunk, chest pains can be observed, which can radiate to the shoulder. These pains are very similar to heart disease.

To prevent diseases of the autonomic nervous system, a person should follow a number of simple rules:

1) avoid nervous fatigue, colds;

2) observe safety precautions in production with hazardous working conditions;

3) eat well;

4) go to the hospital in a timely manner, complete the entire prescribed course of treatment.

And the last point, timely admission to the hospital and full walkthrough the prescribed course of treatment is the most important. This follows from the fact that delaying your visit to the doctor for too long can lead to the most unfortunate consequences.

Good nutrition also plays an important role, because a person "charges" his body, gives him new strength. Having refreshed, the body begins to fight diseases several times more actively. In addition, fruits contain many beneficial vitamins that help the body fight disease. The most useful fruits are in their raw form, because when they are harvested, many beneficial features may disappear. A number of fruits, in addition to containing vitamin C, also have a substance that enhances the action of vitamin C. This substance is called tannin and is found in quinces, pears, apples, and pomegranates.

Development of the nervous system in ontogeny. Characteristics of the three-bubble and five-bubble stages of brain formation

ontogeny, or individual development The body is divided into two periods: prenatal (intrauterine) and postnatal (after birth). The first continues from the moment of conception and the formation of the zygote until birth; the second - from the moment of birth to death.

prenatal period in turn is divided into three periods: initial, embryonic and fetal. The initial (pre-implantation) period in humans covers the first week of development (from the moment of fertilization to implantation in the uterine mucosa). Embryonic (prefetal, embryonic) period - from the beginning of the second week to the end of the eighth week (from the moment of implantation to the completion of organ laying). The fetal (fetal) period begins from the ninth week and lasts until birth. At this time, there is an increased growth of the body.

postnatal period ontogenesis is divided into eleven periods: 1st - 10th day - newborns; 10th day - 1 year - infancy; 1-3 years - early childhood; 4-7 years - the first childhood; 8-12 years - the second childhood; 13-16 years - adolescence; 17-21 years old - youthful age; 22-35 years - the first mature age; 36-60 years - the second mature age; 61-74 years- elderly age; from 75 years old - senile age, after 90 years old - long-livers.

Ontogeny ends with natural death.

The nervous system develops from three main formations: neural tube, neural crest and neural placodes. The neural tube is formed as a result of neurulation from the neural plate - a section of the ectoderm located above the notochord. According to the theory of Shpemen's organizers, chord blastomeres are capable of secreting substances - inductors of the first kind, as a result of which the neural plate bends inside the body of the embryo and a neural groove is formed, the edges of which then merge, forming a neural tube. The closure of the edges of the neural groove begins in the cervical region of the body of the embryo, spreading first to the caudal part of the body, and later to the cranial.

The neural tube gives rise to the central nervous system, as well as neurons and gliocytes of the retina. Initially, the neural tube is represented by a multi-row neuroepithelium, the cells in it are called ventricular. Their processes facing the cavity of the neural tube are connected by nexuses, the basal parts of the cells lie on the subpial membrane. The nuclei of neuro-epithelial cells change their location depending on the phase of the cell life cycle. Gradually, by the end of embryogenesis, ventricular cells lose their ability to divide and give rise to neurons and various types of gliocytes in the postnatal period. In some areas of the brain (germinal or cambial zones), ventricular cells do not lose their ability to divide. In this case, they are called subventricular and extraventricular. Of these, in turn, neuroblasts differentiate, which, no longer having the ability to proliferate, undergo changes during which they turn into mature nerve cells - neurons. The difference between neurons and other cells of their differon (cell row) is the presence of neurofibrils in them, as well as processes, while the axon (neuritis) appears first, and later - dendrites. The processes form connections - synapses. Total, differon nervous tissue represented by neuroepithelial (ventricular), subventricular, extraventricular cells, neuroblasts and neurons.

Unlike macroglial gliocytes, which develop from ventricular cells, microglial cells develop from the mesenchyme and enter the macrophage system.

The cervical and trunk parts of the neural tube give rise to the spinal cord, the cranial part differentiates into the head. The cavity of the neural tube turns into a spinal canal connected to the ventricles of the brain.

The brain undergoes several stages in its development. Its departments develop from the primary cerebral vesicles. At first there are three of them: front, middle and diamond-shaped. By the end of the fourth week, the anterior cerebral vesicle is divided into the rudiments of the telencephalon and diencephalon. Shortly thereafter, the rhomboid bladder also divides, giving rise to the hindbrain and medulla oblongata. This stage of brain development is called the stage of five brain bubbles. The time of their formation coincides with the time of the appearance of the three bends of the brain. First of all, a parietal bend is formed in the region of the middle cerebral bladder, its bulge is turned dorsally. After it, an occipital bend appears between the rudiments of the medulla oblongata and spinal cord. Its convexity is also turned dorsally. The last to form a bridge bend between the two previous ones, but it bends ventrally.

The cavity of the neural tube in the brain is transformed first into the cavity of three, then five bubbles. The cavity of the rhomboid bladder gives rise to the fourth ventricle, which is connected through the aqueduct of the midbrain (the cavity of the middle cerebral bladder) with the third ventricle, formed by the cavity of the rudiment of the diencephalon. The cavity of the initially unpaired rudiment of the telencephalon is connected through the interventricular opening with the cavity of the rudiment of the diencephalon. In the future, the cavity of the terminal bladder will give rise to the lateral ventricles.

The walls of the neural tube at the stages of formation of the cerebral vesicles will thicken most evenly in the region of the midbrain. The ventral part of the neural tube is transformed into the legs of the brain (midbrain), gray tubercle, funnel, posterior pituitary gland (midbrain). Its dorsal part turns into a plate of the roof of the midbrain, as well as the roof of the third ventricle with the choroid plexus and the epiphysis. The lateral walls of the neural tube in the region of the diencephalon grow, forming visual tubercles. Here, under the influence of inductors of the second kind, protrusions are formed - eye vesicles, each of which will give rise to an eye cup, and later - the retina. Inductors of the third kind, located in the eye cups, affect the ectoderm above itself, which laces up inside the glasses, giving rise to the lens.

Very clear, concise and clear. Posted as a keepsake.

1. What is the nervous system

One of the components of a person is his nervous system. It is reliably known that diseases of the nervous system adversely affect physical condition the whole human body. With a disease of the nervous system, both the head and the heart (the “motor” of a person) begin to hurt.

Nervous system is a system that regulates the activity of all human organs and systems. This system causes:

1) the functional unity of all human organs and systems;

2) the connection of the whole organism with the environment.

The nervous system also has its own structural unit, which is called a neuron. Neurons are cells that have special processes. It is neurons that build neural circuits.

The entire nervous system is divided into:

1) central nervous system;

2) peripheral nervous system.

The central nervous system includes the brain and spinal cord, and the peripheral nervous system includes the cranial and spinal nerves and nerve nodes extending from the brain and spinal cord.

Also conditionally, the nervous system can be divided into two large sections:

1) somatic nervous system;

2) autonomic nervous system.

somatic nervous system connected with human body. This system is responsible for the fact that a person can move independently, it also determines the connection of the body with the environment, as well as sensitivity. Sensitivity is provided with the help of human sense organs, as well as with the help of sensitive nerve endings.

The movement of a person is ensured by the fact that with the help of the nervous system, skeletal muscle mass is controlled. Biologists call the somatic nervous system in another way animal, because movement and sensitivity are characteristic only of animals.

Nerve cells can be divided into two large groups:

1) afferent (or receptor) cells;

2) efferent (or motor) cells.

Receptor nerve cells perceive light (using visual receptors), sound (using sound receptors), smells (using olfactory and taste receptors).

Motor nerve cells generate and transmit impulses to specific executing organs. The motor nerve cell has a body with a nucleus, numerous processes called dendrites. The nerve cell also nerve fiber called an axon. The length of these axons ranges from 1 to 1.5 mm. With their help, electrical impulses are transmitted to specific cells.

In the cell membranes that are responsible for the sensation of taste and smell, there are special biological compounds that react to a particular substance by changing their state.

In order for a person to be healthy, he must first of all monitor the state of his nervous system. Today, people sit in front of the computer a lot, stand in traffic jams, and also get into various stressful situations (for example, a student received negative evaluation or the employee received a reprimand from his immediate superiors) - all this negatively affects our nervous system. Today, enterprises and organizations create rest rooms (or relaxation rooms). Arriving in such a room, the worker mentally disconnects from all problems and just sits and relaxes in a favorable environment.

Employees law enforcement(police, prosecutors, etc.) created, one might say, their own system for the protection of their own nervous system. Victims often come to them and talk about the misfortune that happened to them. If a law enforcement officer, as they say, takes to heart what happened to the victims, then he will retire as an invalid, if at all his heart can withstand until retirement. Therefore, law enforcement officers put, as it were, a “protective screen” between themselves and the victim or the criminal, that is, the problems of the victim, the criminal are listened to, but an employee, for example, of the prosecutor’s office, does not express any human participation in them. Therefore, it is not uncommon to hear that all law enforcement officers are heartless and very evil people. In fact, they are not like that - they just have such a method of protecting their own health.

2. Autonomic nervous system

autonomic nervous system is one of the parts of our nervous system. The autonomic nervous system is responsible for: activity internal organs, the activity of the glands of internal and external secretion, the activity of blood and lymphatic vessels, and also in some part of the muscles.

The autonomic nervous system is divided into two sections:

1) sympathetic section;

2) parasympathetic section.

Sympathetic nervous system dilates the pupil, it also causes an increase in heart rate, an increase in blood pressure, expands the small bronchi, etc. This nervous system is carried out by sympathetic spinal centers. It is from these centers that peripheral sympathetic fibers begin, which are located in the lateral horns of the spinal cord.

parasympathetic nervous system is responsible for the activity of the bladder, genitals, rectum, and it also “irritates” a number of other nerves (for example, glossopharyngeal, oculomotor nerve). Such a "diverse" activity of the parasympathetic nervous system is explained by the fact that its nerve centers are located both in the sacral spinal cord and in the brain stem. Now it becomes clear that those nerve centers that are located in the sacral spinal cord control the activity of organs located in the small pelvis; nerve centers located in the brain stem regulate the activity of other organs through a number of special nerves.

Also, these diseases can be acquired. For example, due to a head injury, chronic poisoning with mercury, arsenic, due to a dangerous infectious disease. They can also occur when a person is overworked, with a lack of vitamins, with severe mental disorders and experiences. Also, diseases of the autonomic nervous system can be the result of non-compliance with safety regulations at work with dangerous working conditions.

The regulatory activity of the autonomic nervous system may be impaired. Diseases can "mask" as other diseases. For example, with a disease of the solar plexus, bloating, poor appetite can be observed; with a disease of the cervical or thoracic nodes of the sympathetic trunk, chest pains can be observed, which can radiate to the shoulder. These pains are very similar to heart disease.

To prevent diseases of the autonomic nervous system, a person should follow a number of simple rules:

1) avoid nervous fatigue, colds;

2) observe safety precautions in production with hazardous working conditions;

3) eat well;

4) go to the hospital in a timely manner, complete the entire prescribed course of treatment.

Moreover, the last point, timely admission to the hospital and complete completion of the prescribed course of treatment, is the most important. This follows from the fact that delaying your visit to the doctor for too long can lead to the most unfortunate consequences.

Good nutrition also plays an important role, because a person "charges" his body, gives him new strength. Having refreshed, the body begins to fight diseases several times more actively. In addition, fruits contain many beneficial vitamins that help the body fight disease. The most useful fruits are in their raw form, because when they are harvested, many useful properties can disappear. A number of fruits, in addition to containing vitamin C, also have a substance that enhances the action of vitamin C. This substance is called tannin and is found in quinces, pears, apples, and pomegranates.

3. Central nervous system

The human central nervous system consists of the brain and spinal cord.

1) cervical thickening;

2) lumbar thickening.

It is in these thickenings that the so-called innervation nerves of the upper and lower extremities are formed. Dorsal brain is divided into several departments:

1) cervical;

2) thoracic region;

3) lumbar;

4) sacral department.

The human brain is located in the cranial cavity. It has two hemispheres: right hemisphere and left hemisphere. But, in addition to these hemispheres, the trunk and cerebellum are also isolated. Scientists have calculated that the brain of a man is heavier than the brain of a woman by an average of 100 gm. They explain this by the fact that most men are much larger than women in terms of their physical parameters, that is, all parts of a man's body are larger than parts of a woman's body. The brain actively begins to grow even when the child is still in the womb. The brain reaches its "real" size only when a person reaches the age of twenty. At the very end of a person's life, his brain becomes a little lighter.

There are five main divisions in the brain:

1) telencephalon;

2) diencephalon;

3) midbrain;

4) hindbrain;

5) medulla oblongata.

If a person has suffered a traumatic brain injury, then this always negatively affects both his central nervous system and his mental state.

When the psyche is disturbed, a person can hear voices inside the head that command him to do this or that. All attempts to silence these voices are futile, and in the end man goes and does what the voices tell him to do.

In the hemisphere, the olfactory brain and basal nuclei are distinguished. Also, everyone knows this joke phrase: "Strain your brains", that is, think. Indeed, the "drawing" of the brain is very complex. The complexity of this "pattern" is predetermined by the fact that furrows and ridges go along the hemispheres, which form a kind of "gyrus". Despite the fact that this "drawing" is strictly individual, there are several common furrows. Thanks to these common furrows, biologists and anatomists have identified 5 lobes of the hemispheres:

1) frontal lobe;

2) parietal lobe;

3) occipital lobe;

4) temporal lobe;

5) hidden share.

The brain and spinal cord are covered with membranes:

1) dura mater;

2) arachnoid;

3) soft shell.

Soft shell. The pia mater of the spinal cord and brain contains nerves and blood vessels, which, in fact, feed both brains.

In general, what the brain is, mankind will not find out to the end soon. It is constantly evolving and developing. It is believed that the brain is the "residence" of the human mind.

About that, a person learns in school years. In biology lessons general information about the body as a whole and about individual organs in particular. As part of school curriculum children learn that the normal functioning of the body depends on the state of the nervous system. When failures occur in it, the work of other organs is disrupted. There are various factors that, to one degree or another, influence. nervous system characterized as one of the most important parts of the body. It determines the functional unity of the internal structures of a person and the connection of the organism with the external environment. Let's take a closer look at what is

Structure

To understand what the nervous system is, it is necessary to study all its elements separately. As structural unit the neuron appears. It is a cell with processes. Circuits are formed from neurons. Speaking about what the nervous system is, it should also be said that it consists of two sections: central and peripheral. The first includes the spinal cord and brain, the second - the nerves and nodes extending from them. Conventionally, the nervous system is divided into autonomic and somatic.

Cells

They are divided into 2 large groups: afferent and efferent. The activity of the nervous system starts with receptors. They perceive light, sound, smells. Efferent - motor - cells generate and direct impulses to certain organs. They consist of a body and a nucleus, numerous processes called dendrites. In isolated fiber - axon. Its length can be 1-1.5 mm. Axons provide the transmission of impulses. In the cell membranes responsible for the perception of smell and taste, there are special compounds. They react to certain substances by changing their state.

Vegetative department

The activity of the nervous system provides the work of internal organs, glands, lymphatic and blood vessels. To a certain extent, it also determines the functioning of the muscles. In the autonomic system, parasympathetic and sympathetic divisions are distinguished. The latter provides for the expansion of the pupil and small bronchi, increased pressure, increased heart rate, etc. The parasympathetic department is responsible for the functioning of the genitals, bladder, and rectum. Impulses emanate from it, activating other glossopharyngeal, for example). The centers are located in the trunk of the head and sacral part of the spinal cord.

Pathologies

Diseases of the autonomic system can be caused by various factors. Quite often, disorders are the result of other pathologies, such as TBI, poisoning, infections. Failures in the vegetative system can be caused by a lack of vitamins, frequent stress. Often diseases are "masked" by other pathologies. For example, if the functioning of the thoracic or cervical nodes of the trunk is disturbed, pain in the sternum is noted, radiating to the shoulder. Such symptoms are characteristic of heart disease, so patients often confuse the pathology.

Spinal cord

Outwardly, it resembles a heavy. The length of this section in an adult is about 41-45 cm. There are two thickenings in the spinal cord: lumbar and cervical. They form the so-called innervation structures of the lower and upper limbs. In the following departments are distinguished: sacral, lumbar, thoracic, cervical. Throughout its length, it is covered with soft, hard and arachnoid shells.

Brain

It is located in the cranium. The brain consists of the right and left hemispheres, brainstem and cerebellum. It has been established that its weight in men is greater than in women. The brain begins its development in the embryonic period. The body reaches its real size by about 20 years. By the end of life, the weight of the brain decreases. It has departments:

Finite.
Intermediate.
Average.
Rear.
Oblong.

hemispheres

They also have an olfactory center. The outer shell of the hemispheres has a rather complex pattern. This is due to the presence of ridges and furrows. They form a kind of "convolutions". Each person has a unique drawing. However, there are several furrows that are the same for everyone. They allow you to distinguish five lobes: frontal, parietal, occipital, temporal and hidden.

Unconditioned reflexes

Nervous system processes- response to stimuli. Unconditioned reflexes were studied by such a prominent Russian scientist as IP Pavlov. These reactions are focused mainly on the self-preservation of the organism. The main ones are food, orientation, defensive. Unconditioned reflexes are innate.

Classification

Unconditioned reflexes were studied by Simonov. The scientist singled out 3 classes of innate reactions corresponding to the development of a particular area of the environment:

Orienting reflex

It is expressed in involuntary sensory attention, accompanied by an increase in muscle tone. A reflex is evoked by a new or unexpected stimulus. Scientists call this reaction "alarming", anxiety, surprise. There are three phases of its development:

Cessation of current activity, fixation of posture. Simonov calls this general (preventive) inhibition. It occurs on the appearance of any stimulus with an unknown signal.
Transition to the "activation" reaction. At this stage, the body is transferred to a reflex readiness for a likely meeting with emergency. This is manifested in a general increase in muscle tone. In this phase, a multicomponent reaction takes place. It includes turning the head, eyes towards the stimulus.
Fixation of the stimulus field to start a differentiated analysis of signals and select a response.

Meaning

The orienting reflex is included in the structure of exploratory behavior. This is especially evident in new environment. Research activities can be focused both on the development of novelty and on the search for an object that can satisfy curiosity. In addition, it can also provide an analysis of the significance of the stimulus. In such a situation, an increase in the sensitivity of the analyzers is noted.

Mechanism

The implementation of the orienting reflex is a consequence of the dynamic interaction of many formations of nonspecific and specific elements of the CNS. The general activation phase, for example, is associated with the initiation and onset of generalized cortical excitation. When analyzing the stimulus, cortical-limbic-thalamic integration is of primary importance. Important role it belongs to the hippocampus.

Conditioned reflexes

At the turn of the 19th-20th centuries. Pavlov, who studied the work of the digestive glands for a long time, revealed the following phenomenon in experimental animals. An increase in the secretion of gastric juice and saliva occurred regularly, not only when food directly entered the gastrointestinal tract, but also while waiting for it to be received. At that time, the mechanism of this phenomenon was not known. Scientists explained it by "mental stimulation" of the glands. In the course of subsequent research, Pavlov attributed such a reaction to conditioned (acquired) reflexes. They can come and go over the course of a person's life. For the appearance conditioned response it is necessary that two stimuli coincide. One of them in any conditions provokes a natural response - without conditioned reflex. The second, due to its routine, does not provoke any reaction. It is defined as indifferent (indifferent). In order for a conditioned reflex to arise, the second stimulus must begin to act earlier than the unconditioned reflex by a few seconds. At the same time, the biological significance of the former should be less.

Nervous system protection

As you know, a variety of factors affect the body. State of the nervous system affects other organs. Even seemingly minor failures can cause serious illness. At the same time, they will not always be associated with the activity of the nervous system. In this connection great attention should be given preventive measures. First of all, it is necessary to reduce irritating factors. It is known that constant stress, experiences are one of the causes of cardiac pathologies. The treatment of these diseases includes not only medicines, but also physiotherapy, exercise therapy, etc. Special meaning has a diet. From proper nutrition depends on the state of all systems and organs of a person. Food should contain enough vitamins. Experts recommend including plant foods, herbs, vegetables and fruits in the diet.

Vitamin C

It has a beneficial effect on all body systems, including the nervous system. Due to vitamin C cellular level power generation is provided. This compound is involved in the synthesis of ATP (adenosine triphosphoric acid). Vitamin C is considered one of the strongest antioxidants, it neutralizes negative impact free radicals by binding them. In addition, the substance is able to enhance the activity of other antioxidants. These include vitamin E and selenium.

Lecithin

It ensures the normal course of processes in the nervous system. Lecithin is the main nutrient for cells. Content in peripheral department is about 17%, in the brain - 30%. With insufficient intake of lecithin, nervous exhaustion occurs. The person becomes irritable, which often leads to nervous breakdowns. Lecithin is necessary for all cells of the body. It is included in the B-vitamin group and promotes energy production. In addition, lecithin is involved in the production of acetylcholine.

Music that calms the nervous system

As mentioned above, in diseases of the central nervous system, therapeutic measures may include not only taking medications. The therapeutic course is selected depending on the severity of the violations. Meanwhile, relaxation of the nervous system often achieved without consulting a doctor. A person can independently find ways to relieve irritation. For example, there are different melodies. As a rule, these are slow compositions, often without words. However, a march can also calm some people. When choosing melodies, you should focus on your own preferences. You just need to make sure that the music is not depressing. Today, a special relaxing genre has become quite popular. It combines classical, folk melodies. The main sign of relaxing music is a quiet monotony. It "envelops" the listener, creating a soft but strong "cocoon" that protects the person from external irritations. Relaxing music can be classical, but not symphonic. Usually it is performed by one instrument: piano, guitar, violin, flute. It can also be a song with repeated recitative and simple words.

The sounds of nature are very popular - the rustle of leaves, the sound of rain, bird singing. In combination with the melody of several instruments, they take a person away from the daily hustle and bustle, the rhythm of the metropolis, relieve nervous and muscle tension. When listening, thoughts are ordered, excitement is replaced by calmness.

The nervous system is the highest integrating and coordinating system of the human body, which ensures the coordinated activity of internal organs and the connection of the body with the external environment.

Anatomically, the nervous system is divided into the central (brain and spinal cord); and peripheral, including 12 pairs of cranial nerves, 31 pairs of spinal nerves and nerve nodes located outside the brain and spinal cord.

The function of the nervous system is divided into:

the somatic nervous system - mainly carries out the connection of the body with the external environment: the perception of irritations, the regulation of movements of the striated muscles, etc.

autonomic (autonomous) nervous system - regulates metabolism and the functioning of internal organs: heartbeat, vascular tone, peristaltic contractions of the intestine, secretion of various glands, etc. The autonomic nervous system is divided into parasympathetic and sympathetic nervous systems.

Both of them function in close interaction, however, the autonomic nervous system has some independence, controlling involuntary functions.

The nervous system is made up of nerve cells called neurons. There are 25 billion neurons in the brain, and 25 million cells in the periphery. The bodies of neurons are located mainly in the CNS. Gray matter is a collection of neurons. In the spinal cord, it is located in the center, surrounding the spinal canal. In the brain, on the contrary, the gray matter is located on the surface, forming a cortex and separate clusters - nuclei concentrated in the white matter.

White matter is under gray and is composed of nerve fibers (neuronal processes) covered with sheaths. Nerve ganglions also consist of bodies of neurons. Nerve fibers that extend beyond the CNS and nerve nodes, connecting, compose nerve bundles, and several such bundles form individual nerves.

Centripetal, or sensitive - nerves that conduct excitation from the periphery to the central nervous system. For example, visual, olfactory, auditory.

Centrifugal, or motor - nerves through which excitation is transmitted from the central nervous system to the organs. For example, oculomotor.

Mixed (wandering, spinal), if excitation goes in one direction along one fiber, and in the other direction along the other.

Functions nervous system: regulates the activity of all organs and organ systems, communicates with the external environment through the sense organs; is the material basis for higher nervous activity, thinking, behavior and speech.

The structure and function of the spinal cord.

The spinal cord is located in the spinal canal from the 1st cervical vertebra to the 1st - 2nd lumbar, its length is about 45 cm, thickness is about 1 cm. The anterior and posterior longitudinal grooves divide it into two symmetrical halves. In the center is the spinal canal, which contains the cerebrospinal fluid. In the middle part of the spinal cord, near the spinal canal, there is gray matter, which in cross section resembles the contour of a butterfly. The gray matter is formed by the bodies of neurons, it distinguishes between the anterior and posterior horns. The bodies of intercalary neurons are located in the posterior horns of the spinal cord, and the bodies of motor neurons are located in the anterior horns. In the thoracic region, lateral horns are also distinguished, in which the neurons of the sympathetic part of the autonomic nervous system are located. Surrounding the gray matter is the white matter formed by the nerve fibers. The spinal cord is covered by three membranes:

hard shell - outer, connective tissue, lining the inner cavity of the skull and spinal canal;

arachnoid - located under the solid. This is a thin shell with a small number of nerves and vessels;

the choroid is fused with the brain, enters the furrows and contains many blood vessels.

Fluid-filled cavities form between the vascular and arachnoid membranes.

31 pairs of mixed spinal nerves leave the spinal cord. Each nerve begins with two roots: the anterior (motor), which contains the processes of motor neurons and autonomic fibers, and the posterior (sensory), through which excitation is transmitted to the spinal cord. In the posterior roots are the spinal nodes - clusters of sensory neuron bodies.

Transection of the posterior roots leads to a loss of sensation in those areas that are innervated by the corresponding roots, and transection of the anterior roots leads to paralysis of the innervated muscles.

The functions of the spinal cord are reflex and conduction. As a reflex center, the spinal cord takes part in motor (conducts nerve impulses to the skeletal muscles) and autonomic reflexes. The most important vegetative reflexes of the spinal cord are vasomotor, food, respiratory, defecation, urination, sexual. The reflex function of the spinal cord is under the control of the brain.

The reflex functions of the spinal cord can be examined on the spinal preparation of a frog (without a brain), which retains the simplest motor reflexes. She withdraws her paw in response to mechanical and chemical stimuli. In humans, in the implementation of the coordination of motor reflexes crucial acquires a brain.

The conduction function is carried out due to the ascending and descending paths of the white matter. Excitation from the muscles and internal organs is transmitted along the ascending paths to the brain, along the descending paths - from the brain to the organs.

The structure and functions of the brain.

There are five sections in the brain: the medulla oblongata; the hindbrain, which includes the bridge and the cerebellum; midbrain; diencephalon and forebrain, represented by the large hemispheres. Up to 80% of brain mass is large hemispheres. The central canal of the spinal cord continues into the brain, where it forms four cavities (ventricles). Two ventricles are located in the hemispheres, the third - in the diencephalon, the fourth - at the level of the medulla oblongata and the bridge. They contain cranial fluid. The brain, as well as the spinal cord, is surrounded by three membranes - connective tissue, arachnoid and vascular.

The medulla oblongata is a continuation of the spinal cord, performs reflex and conduction functions. Reflex functions are associated with the regulation of the work of the respiratory, digestive, and circulatory organs. Here are the centers of protective reflexes - coughing, sneezing, vomiting.

The bridge connects the cerebral cortex with the spinal cord and cerebellum, performing mainly a conductive function.

The cerebellum is formed by two hemispheres, externally covered with a bark of gray matter, under which is white matter. The white matter contains nuclei. The middle part of the cerebellum - the worm - connects its hemispheres. The cerebellum is responsible for coordination, balance and influences muscle tone. When the cerebellum is damaged, there is a decrease in muscle tone and a disorder in the coordination of movements, but after a while other parts of the nervous system begin to perform the functions of the cerebellum, and the lost functions are partially restored. Together with the bridge, the cerebellum is part of the hindbrain.

The midbrain connects all parts of the brain. Here are the centers of skeletal muscle tone, the primary centers of visual and auditory orienting reflexes, which are manifested in the movements of the eyes and head towards stimuli.

Three parts are distinguished in the diencephalon: the visual tubercles (thalamus), the epithalamic region (epithalamus), which includes the pineal gland, and the hypothalamic region (hypothalamus). The subcortical centers of all types of sensitivity are located in the thalamus, excitation from the sense organs comes here, and from here it is transmitted to various parts of the cerebral cortex. The hypothalamus contains higher centers regulation of the autonomic nervous system. He controls persistence internal environment organism. Here are the centers of appetite, thirst, sleep, thermoregulation, i.e. regulation of all types of metabolism. Neurons of the hypothalamus produce neurohormones that regulate the functioning of the endocrine system. In the diencephalon there are also emotional centers: centers of pleasure, fear, aggression. Together with the hindbrain and medulla, the diencephalon is part of the brainstem.

The forebrain is represented by the cerebral hemispheres connected by the corpus callosum. The surface of the forebrain is formed by the cortex, the area of which is about 2200 cm 2. Numerous folds, convolutions and furrows significantly increase the surface of the cortex. The surface of the convolutions is more than two times smaller than the surface of the furrows. The human cortex has from 14 to 17 billion nerve cells arranged in 6 layers, the thickness of the cortex is 2-4 mm. Accumulations of neurons in the depths of the hemispheres form subcortical nuclei. The cerebral cortex consists of 4 lobes: frontal, parietal, temporal and occipital, separated by furrows. In the cortex of each hemisphere, the central sulcus separates the frontal lobe from the parietal, the lateral sulcus separates the temporal lobe, and the parietal-occipital sulcus separates the occipital lobe from the parietal.

In the cortex, sensory, motor and associative zones are distinguished. Sensitive zones are responsible for the analysis of information coming from the sense organs: occipital - for vision, temporal - for hearing, smell and taste; parietal - for skin and joint-muscular sensitivity. Moreover, each hemisphere receives impulses from the opposite side of the body. The motor zones are located in the posterior regions of the frontal lobes, from here come the commands for contraction of the skeletal muscles, their defeat leads to muscle paralysis. Associative zones are located in the frontal lobes of the brain and are responsible for the development of programs for behavior and management of human labor activity; their mass in humans is more than 50% of the total mass of the brain.

A person is characterized by a functional asymmetry of the hemispheres: the left hemisphere is responsible for abstract-logical thinking, speech centers are also located there (Brock's center is responsible for pronunciation, Wernicke's center for understanding speech), the right hemisphere is for figurative thinking, musical and artistic creativity.

Due to the strong development of the cerebral hemispheres, the average mass of the human brain is 1400 g on average.

There are several systems in the human body, including the digestive, cardiovascular, and muscular systems. The nervous one deserves special attention - it makes the human body move, respond to annoying factors, see and think.

The human nervous system is a set of structures that performs function of regulation of absolutely all parts of the body, responsible for movement and sensitivity.

In contact with

Types of the human nervous system

Before answering the question of interest to people: “how does the nervous system work”, it is necessary to understand what it actually consists of and what components it is usually divided into in medicine.

With the types of NS, not everything is so simple - it is classified according to several parameters:

area of localization;
type of management;
method of information transfer;
functional affiliation.

Localization area

The human nervous system in the area of localization is central and peripheral. The first is represented by the brain and bone marrow, and the second consists of nerves and the autonomic network.

The central nervous system performs the functions of regulation of all internal and external organs. She makes them interact with each other. Peripheral is the one that, due to anatomical features, is located outside the spinal cord and brain.

How does the nervous system work? The PNS responds to stimuli by sending signals to the spinal cord and then to the brain. After the organs of the central nervous system process them and again send signals to the PNS, which sets, for example, the leg muscles in motion.

Information transfer method

According to this principle, reflex and neurohumoral systems. The first is the spinal cord, which, without the participation of the brain, is able to respond to stimuli.

Interesting! A person does not control the reflex function, since the spinal cord itself makes decisions. For example, when you touch in a hot surface, your hand immediately withdraws, and at the same time you did not even think to make this movement - your reflexes worked.

Neurohumoral, to which the brain belongs, must initially process information, you can control this process. After that, the signals are sent to the PNS, which carries out the commands of your think tank.

Functional affiliation

Speaking about the parts of the nervous system, one cannot fail to mention the autonomic, which in turn is divided into sympathetic, somatic and parasympathetic.

The autonomic system (ANS) is the department responsible for regulation of the lymph nodes, blood vessels, organs and glands(external and internal secretion).

The somatic system is a collection of nerves found in bones, muscles, and skin. It is they who react to all environmental factors and send data to think tank and then carry out his orders. Absolutely every muscle movement is controlled by somatic nerves.

Interesting! The right side of the nerves and muscles is controlled by the left hemisphere, and the left side by the right.

The sympathetic system is responsible for the release of adrenaline into the blood. controls the heart, lungs and supply of nutrients to all parts of the body. In addition, it regulates the saturation of the body.

Parasympathetic is responsible for reducing the frequency of movements, also controls the functioning of the lungs, some glands, and the iris. Not less than important task- regulation of digestion.

Type of control

Another clue to the question "how does the nervous system work" can be given by a convenient classification by type of control. It is divided into higher and lower activities.

Higher activity controls behavior in environment. All intellectual and creative activity also belongs to the highest.

The lower activity is the regulation of all functions within human body. This type activity makes all body systems a single whole.

The structure and functions of the National Assembly

We have already figured out that the entire NS should be divided into peripheral, central, vegetative and all of the above, but there is still a lot to be said about their structure and functions.

Spinal cord

This body is located in the spinal canal and in fact is a kind of "rope" of nerves. It is divided into gray and white matter, where the first is completely covered by the second.

Interesting! In the section, it is noticeable that the gray matter is woven from the nerves in such a way that it resembles a butterfly. That is why it is often called "butterfly wings".

Total the spinal cord is made up of 31 sections, each of which is responsible for separate group nerves that control certain muscles.

The spinal cord, as already mentioned, can work without the participation of the brain - we are talking about reflexes that are not amenable to regulation. At the same time, it is under the control of the organ of thought and performs a conductive function.

Brain

This body is the least studied, many of its functions still raise many questions in scientific circles. It is divided into five departments:

cerebral hemispheres (forebrain);
intermediate;
oblong;
rear;
average.

The first department makes up 4/5 of the entire mass of the organ. He is responsible for vision, smell, movement, thinking, hearing, sensitivity. The medulla oblongata is an incredibly important center that regulates processes such as heartbeat, breathing, defensive reflexes , secretion of gastric juice and others.

The middle department controls a function such as. The intermediate plays a role in the formation emotional state. Also here are the centers responsible for thermoregulation and metabolism in the body.

The structure of the brain

The structure of the nerve

The NS is a collection of billions of specific cells. To understand how the nervous system works, you need to talk about its structure.

A nerve is a structure that consists of a certain number of fibers. Those, in turn, consist of axons - they are the conductors of all impulses.

The number of fibers in one nerve can vary significantly. Usually it is about one hundred, but there are more than 1.5 million fibers in the human eye.

The axons themselves are covered with a special sheath, which significantly increases the speed of the signal - this allows a person to respond to stimuli almost instantly.

The nerves themselves are also different, and therefore they are classified into the following types:

motor (transmit information from the central nervous system to the muscular system);
cranial (this includes visual, olfactory and other types of nerves);
sensitive (transmit information from the PNS to the CNS);
dorsal (located in and control parts of the body);
mixed (capable of transmitting information in two directions).

The structure of the nerve trunk

We have already dealt with topics such as “Types of the human nervous system” and “How the nervous system works”, but a lot has been left aside. interesting facts worthy of mention:

The number in our body is greater than the number of people on the entire planet Earth.
There are about 90–100 billion neurons in the brain. If all of them are connected in one line, then it will reach about 1 thousand km.
The speed of movement of impulses reaches almost 300 km/h.
After the onset of puberty, the mass of the organ of thinking every year decreases by approximately one gram.
Men's brains are about 1/12 larger than women's.
The largest organ of thought was recorded in a mentally ill person.
CNS cells are practically unrepairable, and severe stress and unrest can seriously reduce their number.
Until now, science has not determined how many percent we use our main thinking organ. Known are the myths that no more than 1%, and geniuses - no more than 10%.
Thinking organ size not at all does not affect mental activity. It was previously believed that men are smarter than the fair sex, but this statement was refuted at the end of the twentieth century.
Alcoholic drinks greatly suppress the function of synapses (the place of contacts between neurons), which significantly slows down mental and motor processes.

We learned what the human nervous system is - it is a complex collection of billions of cells that interact with each other at a speed equal to the movement the fastest cars in the world.