What is the nervous system? Activity of the nervous system, condition and protection

, человек узнает еще в школьные годы. A person learns about the nervous system in school years. Biology lessons provide general information about the body as a whole and about individual organs in particular. Within the school program, children learn that the normal functioning of the body depends on the state of the nervous system. If there are failures in it, the work of other organs is disrupted. There are various factors that affect this to some extent . характеризуют как одно из важнейших звеньев организма. The nervous system is characterized as one of the most important links in 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 us consider in more detail what a nervous system is.

Structure

To understand what a nervous system is, you need to study all of its elements separately. The neuron acts as a structural unit. It is a cage with branches. Neurons form chains. Speaking of what the nervous system is, it should also be said that it consists of two divisions: central and peripheral. The first include the spinal cord and the brain, the second - the nerves and nodes that leave them. Conditionally the nervous system is divided into vegetative and somatic.

Cells

They are divided into 2 large groups: afferent and efferent. начинается с рецепторов. The activity of the nervous system begins with the 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 the nerve cell , a fiber-axon is isolated. Its length can be 1-1.5 mm. Axons provide impulse transmission. In the membranes of cells responsible for the perception of odor and taste, there are special compounds. They react to these or other substances by changing their state.

Vegetative department

обеспечивает работу внутренних органов, желез, лимфатических и кровеносных сосудов. The activity of the nervous system ensures the work of internal organs, glands, lymphatic and blood vessels. To a certain extent, it also determines the functioning of the musculature. In the vegetative system, the parasympathetic and sympathetic departments are distinguished. The latter ensures the dilatation 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. From it emanate pulses that activate other nerves (oculomotor, langocrus, for example). The centers are located in the trunk of the head and sacral parts of the spinal cord.

Pathologies

Diseases of the vegetative system may be due to various factors. Quite often, disorders are a consequence of other pathologies, for example, TBI, poisoning, infections. Failures in the vegetative system can be caused by a lack of vitamins, frequent stresses. Often diseases are "masked" by other pathologies. For example, if the functioning of the thoracic or cervical nodes of the trunk is disturbed, there are pains in the sternum that give to the shoulder. Such symptoms are characteristic of heart disease, so patients often confuse pathologies.

Spinal cord

Outwardly it looks like a burden. The length of this department in an adult is about 41-45 cm. There are two thickening in the spinal cord: lumbar and cervical. They form the so-called innervation structures of the lower and upper extremities. In the spinal cord , the following sections are distinguished: sacral, lumbar, thoracic, cervical. Throughout its length it is covered with soft, hard and arachnoid shells.

Brain

It is located in the skull. The brain consists of the right and left hemispheres, the trunk and the cerebellum. It was found that his weight in men is greater than that of women. Its development begins in the embryonic period. The actual size of the body reaches about 20 years. By the end of life, the weight of the brain decreases. It is distinguished by departments:

1. Finite.
2. Intermediate.
3. Average.
4. Rear.
5. Oblong.

The hemisphere

They contain basal nuclei and 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 "gyri". Each person has a different design. Nevertheless, there are several furrows, the same for all. They allow to distinguish five parts: frontal, parietal, occipital, temporal and latent.

Unconditioned reflexes

– ответная реакция на раздражители. The processes of the nervous system are a response to stimuli. Unconditioned reflexes were studied by a prominent Russian scientist, such as IP Pavlov. These reactions are focused mainly on the self-preservation of the body. The main of them are food, indicative, defensive. Unconditioned reflexes are congenital.

Classification

Unconditioned reflexes were investigated by Simonov. The scientist identified 3 classes of congenital reactions corresponding to the development of a specific area of the environment:

1. Vital. They provide species and individual preservation of the body. Such reflexes include food, orientation, defensive, drinking, regulation of sleep, etc. The criteria for such reactions are: physical death if the corresponding need is not satisfied, and the reaction is realized without the participation of other individuals of the same species.
2. Roleplaying. These reflexes are realized only when interacting with other individuals of the same species. Such reactions form the basis for parental, territorial and other behavior. These reflexes are of particular importance for "empathy," emotional resonance, the creation of a group hierarchy in which each individual has a specific role - the parent, the partner, the cub, the stranger or the host of the range, the slave, the leader, and so on.
3. Reactions of self-development. These reflexes are aimed at mastering the space-time media, they are turned toward the future. Such reactions include research behavior, imitation, resistance, etc.

Approximate reflex

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

1. Termination of current activities, fixation of the posture. Simonov calls this general (preventive) inhibition. It arises on the appearance of any stimulus with an unknown signal.
2. Transition to the reaction of "activation". At this stage the organism is translated into a reflex readiness for a probable meeting with an emergency situation. This manifests itself in a general increase in muscle tone. In this phase, a polycomponent reaction takes place. It involves turning the head, the eye toward the stimulus.
3. Fixation of the stimulus field for the initiation of differentiated signal analysis and selection of the response.

Value

An indicative reflex is part of the structure of research behavior. This is especially evident in the new environment. Research activities can be oriented both to the development of novelty, and to the search for an object capable of satisfying curiosity. In addition, it can also provide an analysis of the significance of the stimulus. In this situation, the sensitivity of the analyzers is increased.

Mechanism

The implementation of the orientation reflex is a consequence of the dynamic interaction of many formations of nonspecific and specific elements of the central nervous system. The phase of general activation, for example, is associated with the launch of the reticular formation and the onset of generalized excitation of the cortex. When analyzing the stimulus, cortical-limbic-thalamic integration is of primary importance. An important role in this case belongs to the hippocampus.

Conditional reflexes

At the turn of the 19-20 centuries. Pavlov, who for a long time studied the work of the digestive glands, revealed the following phenomenon in experimental animals. Increased secretion of gastric juice and saliva occurred regularly not only with direct ingestion of food in the digestive tract, but also when waiting for its receipt. At that time, the mechanism of this phenomenon was not known. The scientists explained it by the "psychic stimulation" of the glands. In subsequent studies, Pavlov attributed this reaction to conditioned (acquired) reflexes. They can arise and disappear during a person's life. For the appearance of a conditioned reaction, it is necessary that two stimuli coincide. One of them provokes a logical response in any conditions - an unconditioned reflex. The second, in view of its routine, does not provoke any reaction. It is defined as indifferent (indifferent). In order for a conditioned reflex to arise, the second stimulus should begin to effect earlier than the unconditioned reflex, for a few seconds. In this case, the biological significance of the former should be less.

Protection of the nervous system

As you know, the body is affected by a variety of factors. сказывается на работе других органов. The state of the nervous system affects the work of other organs. Even insignificant glitches at first glance can become the reasons of serious diseases. In this case, not always they will be associated with the activity of the nervous system. In this regard, great attention should be paid to preventive measures. раздражающих факторов. First of all, it is necessary to reduce the influence on the nervous system of irritating factors. It is known that constant stresses, experiences are one of the causes of heart pathologies. Treatment of these diseases includes not only medicines, but also physiotherapy, exercise therapy, etc. Of particular importance is the diet. From the proper nutrition depends the condition of all human systems and organs. Food should contain enough vitamins. Experts recommend to include in the diet of plant foods, herbs, vegetables and fruits.

Vitamin C

It has a beneficial effect on all body systems, including nervous ones. At the expense of vitamin C at the cellular level, energy production is provided. This compound is involved in the synthesis of ATP (adenosine triphosphate). Vitamin C is considered one of the strongest antioxidants, it neutralizes the negative effects of free radicals by binding them. In addition, the substance is able to enhance the activity of other antioxidants. Among them, vitamin E and selenium.

Lecithin

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

Music that calms the nervous system

As it was said above, in case of CNS diseases, therapeutic measures may include not only the taking of medicines. The therapeutic course is selected depending on the severity of the violations. достигается зачастую и без обращения к врачу. Meanwhile, the relaxation of the nervous system is often achieved without consulting a doctor. A person can find ways to remove irritation. . For example, there are different tunes for calming the nervous system . As a rule, these are slow compositions, often without words. However, some people can soothe and march. When choosing tunes, 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 classic, folk melodies. The main sign of relaxing music is a soft monotone. It "envelops" the listener, creating a soft but firm "cocoon" that protects a person from external stimuli. Relaxing music can be classical, but not symphonic. Usually it is performed by one instrument: a piano, a guitar, a violin, a flute. It can also be a song with a repetitive recitative and simple words. Very popular are the sounds of nature - 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 bustle, the rhythm of a megacity, relieve nervous and muscle tension. When listening, thoughts are arranged, excitement is replaced by calm.