The structure of neurons in the brain. The number of neural connections in the brain improves the quality of human life

The nervous system appears to be the most difficult part human body. It includes about 85 billion nerve and glial cells. To date, scientists have been able to study only 5% of neurons. The other 95% is still a mystery, so numerous studies are being carried out on these components of the human brain.

Consider how the human brain works, namely its cellular structure.

The structure of a neuron consists of 3 main components:

1. Cell body

This part of the nerve cell is the key part, which includes the cytoplasm and nuclei, which together create protoplasm, on the surface of which a membrane boundary is formed, consisting of two layers of lipids. On the membrane surface are proteins representing the shape of globules.

The nerve cells of the cortex consist of bodies containing a nucleus, as well as a number of organelles, including an intensively and efficiently developing rough-shaped scattering area that has active ribosomes.

2. Dendrites and axon

The axon appears to be a long process that effectively adapts to excitatory processes from the human body.

Dendrites have a completely different anatomical structure. Their main difference from the axon is that they have a much shorter length, and are also characterized by the presence of abnormally developed processes that perform the functions of the main site. In this area, inhibitory synapses begin to appear, due to which there is the ability to directly influence the neuron itself.

A significant part of the neurons consists to a greater extent of dendrites, while there is only one axon. One nerve cell has many connections with other cells. In some cases, the number of these links exceeds 25,000.

The synapse is the place where contact process between two cells. The main function is to transmit impulses between various cells, while the frequency of the signal may vary depending on the speed and types of transmission of this signal.

As a rule, in order to start the excitatory process of a nerve cell, several excitatory synapses can act as stimuli.

What is the human triple brain

Back in 1962, neuroscientist Paul McLean identified three human brains, namely:

1. reptilian

This reptilian type of human brain has existed for more than 100 million years. It has a significant impact on the behavioral qualities of a person. Its main function is to manage basic behavior, which includes functions such as:

• Reproduction based on human instincts
• Aggression
• Desire to control everything
• Follow certain patterns
• imitate, deceive
• Fight for influence over others

Also, the human reptilian brain is characterized by such features as composure in relation to others, lack of empathy, complete indifference to the consequences of one's actions in relation to others. Also, this type is not able to recognize an imaginary threat with a real danger. As a result, in some situations, given brain completely subjugates the mind and body of a person.

1. Emotional (limbic system)

It appears to be the brain of a mammal, whose age is about 50 million years.

responsible for such functional features individuals like:

• Survival, self-preservation and self-defense
• Governs social behavior including maternal care and upbringing
• Participates in the regulation of organ functions, smell, instinctive behavior, memory, sleep and wakefulness, and a number of others

This brain is almost completely identical to the brain of animals.

1. Visual

It is the brain that performs the functions of our thinking. In other words, it is the rational mind. It is the youngest structure, the age of which does not exceed 3 million years.

It appears to be what we call reason, which includes such abilities as;

• meditate
• Draw inferences
• Ability to analyze

It is distinguished by the presence of spatial thinking, where characteristic visual images arise.

Classification of neurons

To date, a number of classifications of neuronal cells have been distinguished. One of the most common classifications of neurons is distinguished by the number of processes and the place of their localization, namely:

1. Multipolar. These cells are characterized by a large accumulation in the CNS. They present with one axon and several dendrites.
2. Bipolar. They are characterized by one axon and one dendrite and are located in the retina, olfactory tissue, as well as in the auditory and vestibular centers.

Also, depending on the functions performed, neurons are divided into 3 large groups:

1. Afferent

Responsible for the process of signal transmission from receptors to the central nervous system. They differ as:

• Primary. The primary ones are located in the spinal nuclei, which bind to receptors.
• Secondary. They are located in the visual tubercles and perform the functions of transmitting signals to the overlying departments. This type of cells does not bind to receptors, but receives signals from neurocyte cells.

2. Efferent or motor

This type forms the transmission of impulse to other centers and organs of the human body. For example, motor neurons hemispheres- pyramidal, which transmit a signal to motor neurons spinal cord. A key feature of motor efferent neurons is the presence of an axon of considerable length, which has high speed transmission of the excitation signal.

Efferent nerve cells of different departments cerebral cortex connect these departments. These neural connections in the brain provide relationships within and between the hemispheres, therefore, which are responsible for the functioning of the brain in the process of learning, object recognition, fatigue, etc.

3. Insertion or associative

This type carries out the interaction between neurons, and also processes the data that was transmitted from sensitive cells and then transmits it to other intercalary or motor nerve cells. These cells appear to be smaller than the afferent and efferent cells. Axons are represented by a small extent, but the network of dendrites is quite extensive.

Experts concluded that the immediate nerve cells that are localized in the brain are the associative neurons of the brain, and the rest regulate the activity of the brain outside of itself.

Do nerve cells recover

Modern science pays enough attention to the processes of death and restoration of nerve cells. The whole human body has the ability to recover, but do the nerve cells of the brain have such an opportunity?

Even in the process of conception, the body is tuned to the death of nerve cells.

A number of scientists claim that the number of wiped cells is about 1% per year. Based on this statement, it turns out that the brain would have already worn out up to the loss of the ability to perform elementary things. However, this process does not occur, and the brain continues to function until its death.

Each tissue of the body independently restores itself by dividing "living" cells. However, after a number of studies of the nerve cell, people found that the cell does not divide. It is argued that new brain cells are formed due to neurogenesis, which starts even during prenatal period and continues throughout life.

Neurogenesis is the synthesis of new neurons from precursors - stem cells, which subsequently differentiate and form into mature neurons.

Such a process was first described in 1960, but at that time this process was supported by nothing.

Further research has confirmed that neurogenesis can occur in specific brain regions. One of these areas is the space around the cerebral ventricles. The second site includes the hippocampus, which is located directly near the ventricles. The hippocampus performs the functions of our memory, thinking and emotions.

As a result, the ability to memorize and think is formed in the process of life under the influence of various factors. As can be noted from the foregoing, our brain, although only 5% of its structures have been identified, still highlights a number of facts that confirm the ability of nerve cells to recover.

Conclusion

Do not forget that for the full functioning of nerve cells, you should know how to improve the neural connections of the brain. Many experts note that the main guarantee of healthy neurons is healthy eating and lifestyle, and only then can additional pharmacological support be used.

Organize your sleep, give up alcohol, smoking, and eventually your nerve cells will thank you.

The neural connections in the brain determine complex behavior. Neurons are small computing machines that can only exert influence by networking.

The control of the simplest elements of behavior (for example, reflexes) does not require a large number of neurons, but even reflexes are often accompanied by a person's awareness of the triggering of the reflex. Conscious perception of sensory stimuli (and all higher functions nervous system) depends on a huge number of connections between neurons.

Neural connections make us who we are. Their quality affects the work internal organs, on intellectual abilities and emotional stability.

"Wiring"

The neural connections of the brain are the wiring of the nervous system. The work of the nervous system is based on the ability of a neuron to perceive, process and transmit information to other cells.

Information is transmitted through human behavior and the functioning of his body depends entirely on the transmission and receipt of impulses by neurons through processes.

A neuron has two types of processes: an axon and a dendrite. The axon of a neuron is always one, it is along it that the neuron transmits impulses to other cells. It receives an impulse through dendrites, of which there may be several.

Numerous (sometimes tens of thousands) axons of other neurons are “connected” to the dendrites. Dendrite and axon contact through the synapse.

Neuron and synapses

The gap between the dendrite and the axon is the synapse. Because the axon is the "source" of the impulse, the dendrite is the "receiver", and the synaptic cleft is the place of interaction: the neuron from which the axon comes is called presynaptic; the neuron from which the dendrite originates is postsynaptic.

Synapses can form between an axon and a neuron body, and between two axons or two dendrites. Many synaptic connections are formed by the dendritic spine and the axon. Spines are very plastic, have many shapes, can quickly disappear and form. They are sensitive to chemicals and physical impact(injuries, infectious diseases).

In synapses, information is most often transmitted through mediators ( chemical substances). The mediator molecules are released on the presynaptic cell, cross synaptic cleft and bind to membrane receptors on the postsynaptic cell. Mediators can transmit an excitatory or inhibitory (inhibitory) signal.

Neuronal connections of the brain are the connection of neurons through synaptic connections. Synapses - functional and structural unit nervous system. The number of synaptic connections is a key indicator for brain function.

Receptors

Receptors remember every time they talk about a drug or alcohol addiction. Why does a person need to be guided by the principle of moderation?

The receptor on the postsynaptic membrane is a protein tuned to the molecules of the mediator. When a person artificially (with drugs, for example) stimulates the release of mediators into the synaptic cleft, the synapse tries to restore balance: it reduces the number of receptors or their sensitivity. Because of this, the natural concentration levels of neurotransmitters in the synapse cease to have an effect on neuronal structures.

For example, smoking people nicotine change the susceptibility of receptors to acetylcholine, desensitization (decrease in sensitivity) of receptors occurs. natural level acetylcholine is insufficient for receptors with reduced sensitivity. Because acetylcholine is involved in many processes, including those associated with concentration and comfort, the smoker cannot get beneficial effects work of the nervous system without nicotine.

However, the sensitivity of the receptors is gradually restored. Although it may take for a long time, the synapse returns to normal, and the person no longer needs third-party stimulants.

Development of neural networks

Long-term changes in neuronal connections occur when various diseases(mental and neurological - schizophrenia, autism, epilepsy, Huntington's disease, Alzheimer's and Parkinson's). Synaptic connections and internal properties of neurons change, which leads to disruption of the nervous system.

The activity of neurons is responsible for the development of synaptic connections. "Use it or lose it" is the principle behind the brain. The more often neurons "act", the more connections between them, the less often, the less connections. When a neuron loses all its connections, it dies.

When average level the activity of neurons decreases (for example, due to injury), neurons build new contacts, the activity of neurons increases with the number of synapses. The reverse is also true: as soon as the level of activity becomes more than the usual level, the number of synaptic connections decreases. Similar forms of homeostasis often occur in nature, for example, in the regulation of body temperature and blood sugar levels.

M. Butz M. Butz noted:

The formation of new synapses is due to the desire of neurons to maintain a given level of electrical activity...

Henry Markram, who is involved in a project to create a neural simulation of the brain, highlights the prospects for an industry to study the disruption, repair and development of neural connections. The research team has already digitized 31,000 rat neurons. The neural connections of the rat brain are presented in the video below.

neuroplasticity

The development of neural connections in the brain is associated with the creation of new synapses and the modification of existing ones. The possibility of modifications is due to synaptic plasticity - a change in the "power" of the synapse in response to the activation of receptors on the postsynaptic cell.

A person can remember information and learn thanks to disruption of the neural connections of the brain due to traumatic brain injuries and neurodegenerative diseases due to neuroplasticity does not become fatal.

Neuroplasticity is driven by the need to change in response to new living conditions, but it can both solve a person's problems and create them. A change in synapse strength, for example, when smoking, is also a reflection of brain plasticity. Drugs and obsessive-compulsive disorder are so difficult to get rid of precisely because of the maladaptive change in synapses in neural networks.

On neuroplasticity big influence provided by neurotrophic factors. N.V. Gulyaeva emphasizes that various disorders of neural connections occur against the background of a decrease in the levels of neurotrophins. Normalization of the level of neurotrophins leads to the restoration of neural connections in the brain.

All effective medicines, used to treat brain diseases, regardless of their structure, if they are effective, they normalize local levels of neurotrophic factors by one mechanism or another.

Optimization of neurotrophin levels cannot yet be achieved by their direct delivery to the brain. But a person can indirectly influence the levels of neurotrophins through physical and cognitive loads.

Physical exercise

Reviews of studies show that exercise improves mood and cognitive abilities. Evidence suggests that these effects are due to altered levels of neurotrophic factor (BDNF) and improved cardiovascular health.

High levels of BDNF have been associated with better measures of spatial ability, episodic and Low level BDNF, especially in the elderly, has been correlated with hippocampal atrophy and memory impairment, which may be related to cognitive problems associated with Alzheimer's disease.

When exploring the possibilities for treating and preventing Alzheimer's, researchers often talk about the indispensability of exercise for people. So, studies show that regular walking affects the size of the hippocampus and improves memory.

Physical exercise increase the rate of neurogenesis. Emergence of new neurons important condition for relearning (gaining new experience and erasing the old).

Cognitive Loads

Neural connections in the brain develop when a person is in a stimulus-enriched environment. New experiences are the key to increasing neural connections.

A new experience is a conflict when the problem is not solved by the means that the brain already has. Therefore, he has to create new connections, new patterns of behavior, which is associated with an increase in the density of spines, the number of dendrites and synapses.

Learning new skills leads to the formation of new spines and the destabilization of old spine-axon connections. A person develops new habits, and old ones disappear. Some studies have linked cognitive disorders (ADHD, autism, mental retardation) with deviations in the development of spines.

The spines are very plastic. The number, shape, and size of spines are associated with motivation, learning, and memory.

The time required to change their shape and size is literally measured in hours. But it also means that new connections can disappear just as quickly. Therefore, it is best to prioritize short but frequent cognitive loads over long and infrequent ones.

Lifestyle

Diet can enhance cognition and protect the brain's neural connections from damage, promote recovery from illness, and counteract the effects of aging. Brain health appears to be positively affected by:

- omega-3 (fish, flax seeds, kiwi, nuts);

- curcumin (curry);

- flavonoids (cocoa, green tea, citrus fruits, dark chocolate);

- vitamins of group B;

- Vitamin E (avocados, nuts, peanuts, spinach, Wheat flour);

- choline (chicken, veal, egg yolks).

Majority listed products indirectly affect neurotrophins. positive impact diet is enhanced by the presence of exercise. In addition, moderate caloric restriction in the diet stimulates the expression of neurotrophins.

For the restoration and development of neural connections, the exclusion of saturated fats and refined sugars is useful. Foods with added sugars reduce neurotrophin levels, which negatively affects neuroplasticity. A high content saturated fat in food even inhibits brain recovery after traumatic brain injury.

Among negative factors affecting neural connections: smoking and stress. Smoking and prolonged stress in Lately associated with neurodegenerative changes. Although short-term stress can be a catalyst for neuroplasticity.

The functioning of neural connections also depends on sleep. Perhaps even more than all the other factors listed. Because sleep itself is "the price we pay for brain plasticity" (Sleep is the price we pay for brain plasticity. Ch. Cirelli - C. Cirelli).

Summary

How to improve neural connections in the brain? Positive influence provide:

• physical exercise;
• tasks and difficulties;
• good sleep;
• balanced diet.

Negative impact:

• fatty food and sugar;
• smoking;
• prolonged stress.

The brain is extremely plastic, but it is very difficult to "sculpt" something out of it. He does not like to waste energy on useless things. The fastest development of new connections occurs in a situation of conflict, when a person is not able to solve the problem by known methods.

In this article we will talk about the neurons of the brain. The neurons of the cerebral cortex is the structural and functional unit of the entire general nervous system.

Such a cell has a very complex structure, high specialization, and if we talk about its structure, then the cell consists of a nucleus, a body and processes. There are approximately 100 billion of these cells in the human body.

Functions

Any cells that are located in human body necessarily responsible for one or another of its functions. Neurons are no exception.

They, like other brain cells, are required to maintain their own structure and some functions, as well as to adapt to possible changes conditions, and, accordingly, to carry out regulatory processes on cells that are in close proximity.

main function neurons are considered processing important information, namely its receipt, conduction, and then transfer to other cells. Information comes through synapses that have receptors for sensory organs or some other neurons.

Also, in some situations, the transfer of information can occur directly from the external environment with the help of so-called specialized dendrites. Information is carried through axons, and its transmission is carried out by synapses.

Structure

Cell body. This part of the neuron is considered the most important and consists of the cytoplasm and the nucleus, which create the protoplasm, outside it is limited to a kind of membrane consisting of a double layer of lipids.

In turn, such a layer of lipids, which is also commonly called the biolipid layer, consists of hydrophobic tails and the same heads. It should be noted that such lipids are tails to each other, and thus create a kind of hydrophobic layer that is able to pass through itself only substances that dissolve in fats.

On the surface of the membrane are proteins that are in the form of globules. On such membranes there are outgrowths of polysaccharides, with the help of which the cell has a good opportunity to perceive irritations. external factors. Integral proteins are also present here, which actually penetrate the entire surface of the membrane through and through, and in them, in turn, ion channels are located.

Neuronal cells of the cerebral cortex consist of bodies, the diameter ranges from 5 to 100 microns, which contain a nucleus (having many nuclear pores), as well as some organelles, including a fairly strongly developing rough ER with active ribosomes .

Also, processes are included in each individual cell of a neuron. There are two main types of processes - axon and dendrites. A feature of the neuron is that it has a developed cytoskeleton, which is actually able to penetrate into its processes.

Thanks to the cytoskeleton, the necessary and standard shape of the cell is constantly maintained, and its threads act as a kind of "rails" through which organelles and substances are transported, which are packed into membrane vesicles.

Dendrites and axon. The axon looks like a rather long process, which is perfectly adapted to the processes aimed at excitation of a neuron from the human body.

Dendrites look completely different, if only because their length is much shorter, and they also have overly developed processes that play the role of the main site where inhibitory synapses begin to appear, which can thus affect the neuron, which within a short period of time human neurons are excited.

Typically, a neuron is made up of more dendrites at a time. As there is only one axon. One neuron has connections with many other neurons, sometimes there are about 20,000 such connections.

Dendrites divide in a dichotomous way, in turn, axons are able to give collaterals. Almost every neuron contains several mitochondria at the branch nodes.

It is also worth noting the fact that dendrites do not have any myelin sheath, while axons can have such an organ.

A synapse is a place where contact is made between two neurons or between an effector cell that receives a signal and the neuron itself.

The main function of such a component neuron is the transmission of nerve impulses between different cells, while the frequency of the signal may vary depending on the rate and types of transmission of this signal.

It should be noted that some synapses are able to cause neuron depolarization, while others, on the contrary, hyperpolarize. The first type of neurons are called excitatory, and the second - inhibitory.

As a rule, in order for the process of excitation of a neuron to begin, several excitatory synapses must act as stimuli at once.

Classification

According to the number and localization of dendrites, as well as the location of the axon, brain neurons are divided into unipolar, bipolar, axon-free, multipolar and pseudo-unipolar neurons. Now I would like to consider each of these neurons in more detail.

Unipolar neurons have one small process, and are most often located in the sensory nucleus of the so-called trigeminal nerve located in the middle part of the brain.

Axonless neurons are small in size and located in close proximity to spinal cord, namely in the intervertebral galls and have absolutely no division of processes into axons and dendrites; all processes have almost the same appearance and there are no serious differences between them.

bipolar neurons consist of one dendrite, which is located in special sensory organs, in particular in the eye grid and the bulb, as well as only one axon;

Multipolar neurons have several dendrites and one axon in their own structure, and are located in the central nervous system;

Pseudo-unipolar neurons are considered peculiar in their own way, since at first only one process departs from the main body, which is constantly divided into several others, and such processes are found exclusively in the spinal ganglia.

There is also a classification of neurons according to functional principle. So, according to such data, efferent, afferent, motor, and also interneurons are distinguished.

Efferent neurons have in their composition non-ultimatum and ultimatum subspecies. In addition, they include the primary cells of human sensitive organs.

Afferent neurons. Neurons of this category are treated as primary cells of sensitive human organs, and pseudo-unipolar cells that have dendrites with free endings.

Associative neurons. The main function of this group of neurons is the implementation of communication between afferent efferent types of neurons. Such neurons are divided into projection and commissural.

Development and growth

Neurons begin to develop from a small cell, which is considered its predecessor and stops dividing even before the first own processes are formed.

It should be noted that at the present time, scientists have not yet fully studied the issue of the development and growth of neurons, but they are constantly working in this direction.

In most cases, axons develop first, followed by dendrites. At the very end of the process, which begins to develop steadily, a thickening of a shape specific and unusual for such a cell is formed, and thus a path is paved through the tissue surrounding the neurons.

This thickening is commonly called the growth cone of nerve cells. This cone consists of some flattened part of the process of the nerve cell, which in turn is made up of a large number of rather thin spines.

Microspines have a thickness of 0.1 to 0.2 micromicrons, and in length they can reach 50 microns. Speaking directly about the flat and wide area of ​​the cone, it should be noted that it tends to change its own parameters.

There are some gaps between the microspikes of the cone, which are completely covered by a folded membrane. The microspines move permanent basis, due to which, in case of damage, neurons are restored and acquire the necessary shape.

I would like to note that each individual cell moves in its own way, so if one of them lengthens or expands, then the second may deviate in different sides or even stick to the substrate.

The growth cone is completely filled with membranous vesicles, which are characterized by too small size and irregular shape, as well as connections with each other.

In addition, the growth cone contains neurofilaments, mitochondria, and microtubules. Such elements have the ability to move at great speed.

If we compare the speeds of movement of the elements of the cone and the cone itself, it should be emphasized that they are approximately the same, and therefore it can be concluded that neither assembly nor any disturbances of microtubules are observed during the growth period.

Probably, new membrane material starts to be added already at the very end of the process. The growth cone is a site of rather rapid endocytosis and exocytosis, which is confirmed by a large number of bubbles that are located here.

As a rule, the growth of dendrites and axons is preceded by the moment of migration of neuron cells, that is, when immature neurons actually settle and begin to exist in the same permanent place.

Each structure in the human body consists of specific tissues inherent in the organ or system. IN nervous tissue- neuron (neurocyte, nerve, neuron, nerve fiber). What are brain neurons? This is a structural and functional unit of the nervous tissue, which is part of the brain. In addition to the anatomical definition of a neuron, there is also a functional one - it is a cell excited by electrical impulses that is capable of processing, storing and transmitting information to other neurons using chemical and electrical signals.

The structure of the nerve cell is not so complicated, in comparison with the specific cells of other tissues, it also determines its function. neurocyte consists of a body (another name is soma), and processes - an axon and a dendrite. Each element of the neuron performs its function. The soma is surrounded by a layer of adipose tissue that allows only fat-soluble substances to pass through. Inside the body is the nucleus and other organelles: ribosomes, endoplasmic reticulum and others.

In addition to the neurons themselves, the following cells predominate in the brain, namely: glial cells. They are often referred to as brain glue for their function: glia serve as a support function for neurons, providing an environment for them. Glial tissue allows the nervous tissue to regenerate, nourish and helps in creating a nerve impulse.

The number of neurons in the brain has always been of interest to researchers in the field of neurophysiology. Thus, the number of nerve cells varied from 14 billion to 100. Latest research Brazilian experts found that the number of neurons averages 86 billion cells.

offshoots

The tools in the hands of the neuron are the processes, thanks to which the neuron is able to perform its function as a transmitter and store of information. It is the processes that form a wide nervous network, which allows human psyche unfold in all its glory. There is a myth that mental capacity of a person depend on the number of neurons or on the weight of the brain, but this is not so: those people whose brain fields and subfields are highly developed (several times more) become geniuses. Due to this, the fields responsible for certain functions will be able to perform these functions more creatively and faster.

axon

An axon is a long branch of a neuron that transmits nerve impulses from the soma of the nerve to other similar cells or organs innervated by a certain section of the nerve column. Nature endowed vertebrates with a bonus - myelin fiber, in the structure of which there are Schwann cells, between which there are small empty areas - Ranvier's intercepts. Along them, like a ladder, nerve impulses jump from one area to another. This structure allows you to speed up the transfer of information at times (up to about 100 meters per second). The speed of movement of an electrical impulse along a fiber that does not have myelin averages 2-3 meters per second.

Dendrites

Another type of processes of the nerve cell - dendrites. Unlike a long and unbroken axon, a dendrite is a short and branched structure. This process is not involved in the transmission of information, but only in its receipt. So, excitation comes to the body of a neuron with the help of short branches of dendrites. The complexity of the information a dendrite is able to receive is determined by its synapses (specific nerve receptors), namely its surface diameter. dendrites thanks to a huge number of their spines, are capable of establishing hundreds of thousands of contacts with other cells.

Metabolism in a neuron

A distinctive feature of nerve cells is their metabolism. Metabolism in the neurocyte is distinguished by its high speed and the predominance of aerobic (oxygen-based) processes. This feature of the cell is explained by the fact that the work of the brain is extremely energy-intensive, and its need for oxygen is great. Despite the fact that the weight of the brain is only 2% of the weight of the entire body, its oxygen consumption is approximately 46 ml / min, which is 25% of the total body consumption.

The main source of energy for brain tissue, in addition to oxygen, is glucose where it undergoes complex biochemical transformations. Ultimately, a large amount of energy is released from sugar compounds. Thus, the question of how to improve the neural connections of the brain can be answered: eat foods containing glucose compounds.

Functions of a neuron

Despite the relatively simple structure, the neuron has many functions, the main of which are the following:

• perception of irritation;
• stimulus processing;
• impulse transmission;
• formation of a response.

Functionally, neurons are divided into three groups:

Afferent(sensitive or sensory). The neurons of this group perceive, process and send electrical impulses to the central nervous system. Such cells are anatomically located outside the CNS, but in the spinal neuronal clusters (ganglia), or the same clusters of cranial nerves.

Intermediaries(Also, these neurons that do not extend beyond the spinal cord and brain are called intercalary). The purpose of these cells is to provide contact between neurocytes. They are located in all layers of the nervous system.

Efferent(motor, motor). This category of nerve cells is responsible for the transmission of chemical impulses to the innervated executing organs, ensuring their performance and setting them functional state.

In addition, another group is functionally distinguished in the nervous system - inhibitory (responsible for inhibiting cell excitation) nerves. Such cells counteract the propagation of electrical potential.

Classification of neurons

Nerve cells are diverse as such, so neurons can be classified based on their different parameters and attributes, namely:

• Body shape. IN different departments The brain contains neurocytes of various soma shapes:
  • stellate;
  • spindle-shaped;
  • pyramidal (Betz cells).
• By the number of shoots:
  • unipolar: have one process;
  • bipolar: two processes are located on the body;
  • multipolar: three or more processes are located on the soma of such cells.
• Contact features of the neuron surface:
  • axo-somatic. In this case, the axon contacts the soma of the neighboring cell of the nervous tissue;
  • axo-dendritic. This type of contact involves the connection of an axon and a dendrite;
  • axo-axonal. The axon of one neuron has connections with the axon of another nerve cell.

Types of neurons

In order to carry out conscious movements, it is necessary that the impulse formed in the motor convolutions of the brain be able to reach necessary muscles. Thus, allocate the following types neurons: central motor neuron and peripheral one.

The first type of nerve cells originates from the anterior central gyrus, located in front of the largest sulcus of the brain - namely, from Betz's pyramidal cells. Further, the axons of the central neuron deepen into the hemispheres and pass through the inner capsule of the brain.

Peripheral motor neurocytes are formed by motor neurons of the anterior horns of the spinal cord. Their axons reach various formations, such as plexuses, spinal nerve clusters, and, most importantly, performing muscles.

Development and growth of neurons

A nerve cell originates from a precursor cell. Developing, the first begin to grow axons, dendrites mature somewhat later. At the end of the evolution of the neurocyte process, a small compaction forms near the soma of the cell. irregular shape. This formation is called a growth cone. It contains mitochondria, neurofilaments and tubules. The receptor systems of the cell gradually mature and the synaptic regions of the neurocyte expand.

Conducting paths

The nervous system has its spheres of influence throughout the body. Conductive fibers are used to nervous regulation systems, organs and tissues. The brain, thanks to a wide system of pathways, completely controls the anatomical and functional state of any structure of the body. Kidneys, liver, stomach, muscles and others - all this is inspected by the brain, carefully and painstakingly coordinating and regulating every millimeter of tissue. And in case of failure - corrects and selects suitable model behavior. Thus, thanks to the pathways, the human body is distinguished by autonomy, self-regulation and adaptability to the external environment.

Pathways of the brain

A pathway is a collection of nerve cells whose function is to exchange information between various sites body.

• Associative nerve fibers. These cells connect different nerve centers that are located in the same hemisphere.
• commissural fibers. This group is responsible for the exchange of information between similar centers of the brain.
• Projective nerve fibers. This category of fibers articulates the brain with the spinal cord.
• exteroceptive pathways. They carry electrical impulses from the skin and other sense organs to the spinal cord.
• Proprioceptive. This group of pathways carry signals from tendons, muscles, ligaments, and joints.
• Interoceptive pathways. The fibers of this tract originate from the internal organs, vessels and intestinal mesentery.

Interaction with neurotransmitters

Neurons of different locations communicate with each other using electrical impulses. chemical nature. So, what is the basis of their education? There are so-called neurotransmitters (neurotransmitters) - complex chemical compounds. On the surface of the axon is nerve synapse- contact surface. On one side is the presynaptic cleft, and on the other is the postsynaptic cleft. There is a gap between them - this is the synapse. On the presynaptic part of the receptor, there are sacs (vesicles) containing a certain amount of neurotransmitters (quantum).

When the impulse approaches the first part of the synapse, a complex biochemical cascade mechanism is initiated, as a result of which the sacs with mediators are opened, and the quanta of mediator substances smoothly flow into the gap. At this stage, the impulse disappears and reappears only when the neurotransmitters reach the postsynaptic cleft. Then biochemical processes are activated again with the opening of the gate for mediators, and those, acting on the smallest receptors, are converted into an electrical impulse, which goes further into the depths of the nerve fibers.

Meanwhile, allocate different groups these same neurotransmitters, namely:

• Inhibitory neurotransmitters are a group of substances that have an inhibitory effect on excitation. These include:
  • gamma-aminobutyric acid (GABA);
  • glycine.
• Excitatory mediators:
  • acetylcholine;
  • dopamine;
  • serotonin;
  • norepinephrine;
  • adrenalin.

Do nerve cells recover

For a long time it was thought that neurons were incapable of dividing. However, such a statement, according to modern research, turned out to be false: in some parts of the brain, the process of neurogenesis of the precursors of neurocytes occurs. In addition, brain tissue has an outstanding capacity for neuroplasticity. There are many cases when a healthy part of the brain takes over the function of a damaged one.

Many experts in the field of neurophysiology wondered how to restore brain neurons. Fresh research by American scientists revealed that for the timely and proper regeneration of neurocytes, you do not need to use expensive drugs. To do this, you just need to make the right sleep schedule and eat right with the inclusion of B vitamins and low-calorie foods in the diet.

If there is a violation of the neural connections of the brain, they are able to recover. However, there are serious pathologies nerve connections and ways like sickness motor neuron. Then you need to contact a specialized clinical care where neurologists can find out the cause of the pathology and make the right treatment.

People who have previously used or used alcohol often ask the question of how to restore brain neurons after alcohol. The specialist would answer that for this it is necessary to systematically work on your health. The set of activities includes balanced diet, regular exercise, mental activity, walking and traveling. It has been proven that the neural connections of the brain develop through the study and contemplation of information that is categorically new to a person.

In the context of a glut of unnecessary information, the existence of a fast food market and a sedentary lifestyle, the brain lends itself qualitatively to various damage. Atherosclerosis, thrombotic formation on the vessels, chronic stress, infections - all this is a direct road to clogging the brain. Despite this, there are drugs that restore brain cells. The main and popular group is nootropics. Preparations of this category stimulate the metabolism in neurocytes, increase resistance to oxygen deficiency and have a positive effect on various mental processes(memory, attention, thinking). In addition to nootropics, the pharmaceutical market offers drugs containing nicotinic acid, strengthening the walls of blood vessels, and others. It should be remembered that the restoration of neural connections of the brain when taking various drugs is a long process.

The effect of alcohol on the brain

Alcohol renders Negative influence on all organs and systems, and especially on the brain. Ethanol easily penetrates the protective barriers of the brain. Alcohol metabolite - acetaldehyde - serious threat for neurons: alcohol dehydrogenase (an enzyme that processes alcohol in the liver) in the process of processing by the body pulls more quantity fluids, including water from the brain. Thus, alcohol compounds simply dry the brain, pulling water out of it, as a result of which brain structures atrophy and cell death occurs. In the case of a single use of alcohol, such processes are reversible, which cannot be said about chronic alcohol intake, when, in addition to organic changes, stable pathocharacterological features of an alcoholic are formed. More detailed information about how "The Effect of Alcohol on the Brain" happens.

Our body is made up of countless cells. Approximately 100,000,000 of them are neurons. What are neurons? What are the functions of neurons? Are you curious to know what task they perform and what you can do with them? Let's consider this in more detail.

Functions of neurons

Have you ever thought about how information passes through our body? Why, if something hurts us, do we immediately unconsciously pull our hand back? Where and how do we recognize this information? All this is the action of neurons. How do we understand that this is cold, and this is hot ... and this is soft or prickly? Neurons are responsible for receiving and transmitting these signals throughout our body. In this article, we will talk in detail about what a neuron is, what it consists of, what is the classification of neurons and how to improve their formation.

Basic concepts about the functions of neurons

Before talking about what the functions of neurons are, it is necessary to define what a neuron is and what it consists of.

Do you want to know how your brain works? What are your strong and possibly weak cognitive functions? Are there any symptoms that indicate the presence of any disorder? What abilities can be improved? Get answers to all these questions in less than 30-40 minutes by going through