The autonomic nervous system regulates muscle function. Autonomic nervous system (ANS). Sympathetic and parasympathetic divisions

The nerve centers of the autonomic nervous system are located in medulla oblongata, hypothalamus, limbic system of the brain. Higher department of regulation – diencephalon nuclei . The fibers of the autonomic nervous system also approach the skeletal muscles, but do not cause its contraction, but increase metabolism in the muscles.

The autonomic nervous system (ANS) regulates the work internal organs And metabolism , reduction smooth muscle .

The path from the center to the innervated organ in the system consists of two neurons, which are located in the central nervous system and autonomic nuclei, respectively. The fibers of the autonomic nervous system emerge from the nuclear formations of the central nervous system and are necessarily interrupted in the peripheral autonomic nerve ganglia. This is a typical sign of the autonomic nervous system. In contrast, in the somatic nervous system, which innervates skeletal muscles, skin, ligaments, tendons, nerve fibers from the central nervous system reach the innervated organ without interruption.

The autonomic nervous system is divided into two sections: parasympathetic – responsible for resource recovery; sympathetic – responsible for activities in extreme conditions. The departments have opposite effects on the same organs and organ systems.

Diagram of the structure of the autonomic nervous system

first neuron second neuron working organ

CNS autonomic nuclei

(nodes, ganglia)

preganglionic postganglionic

fibers (nerves) fibers (nerves)

Functions of VNS departments

Topic 5. Higher nervous activity

Higher nervous activity (HNA) – a set of complex forms of activity of the cerebral cortex and the subcortical formations closest to them, ensuring the interaction of the whole organism with the environment.

GNI is based on analysis And synthesis information.

GND is carried out through reflex activity (reflexes).

Conditioned reflexes are always developed on the basis of unconditioned ones.

Unconditioned reflexes– congenital, specific (present in all individuals of a given species), arise under the action of an adequate stimulus (stimulus to which the organism is evolutionarily adapted), and persist throughout life. They can be carried out at the level of the spinal cord and pons, the medulla oblongata, and ensure the maintenance of the body’s vital functions in relatively constant conditions of existence.

Conditioned reflexes– acquired, individual, require special conditions to occur, are formed in response to any irritants. They fade away during life. They are carried out at the level of the cerebral cortex and subcortical formations. Provide adaptation to changing environmental conditions.

To form a conditioned reflex, it is necessary: ​​a conditioned stimulus (any stimulus from the external environment or a certain change in the internal state of the body); an unconditioned stimulus that causes an unconditioned reflex; time. The conditioned stimulus should precede the unconditioned stimulus by 5–10 seconds.

Initially, a conditioned stimulus (for example, a bell) causes a generalized reaction of the body - orientation reflex, or reflex “what is it?” . Motor activity appears, breathing and heart rate increase. After a 5–10 second break, this stimulus is reinforced with an unconditioned stimulus (for example, food). In this case, two foci of excitation will appear in the cerebral cortex - one in the auditory zone, the other in the food center. After several reinforcements, a temporary connection will arise between these areas.

The closure occurs not only along horizontal fibers bark-bark , but also along the way cortex-subcortex-bark .

The mechanism of formation of a conditioned reflex is carried out according to the principle of dominance (Ukhtomsky). In the nervous system at each moment of time there are dominant foci of excitation - dominant foci. It is believed that during the formation of a conditioned reflex, the focus of persistent excitation that arises in the center of the unconditioned reflex “attracts” to itself the excitation that arises in the center of the conditioned stimulus. As these two excitations combine, a temporary connection is formed.

A) muscles of the upper and lower extremities,

B) heart and blood vessels,

B) digestive organs,

D) facial muscles,

D) kidneys and bladder,

E) diaphragm and intercostal muscles.

AT 3. The peripheral nervous system includes:

B) cerebellum,

B) nerve nodes

D) spinal cord,

D) sensory nerves

E) motor nerves.

AT 4. The cerebellum contains regulatory centers:

A) muscle tone,

B) vascular tone,

B) body posture and balance,

D) coordination of movements,

D) emotions

E) inhalation and exhalation.

Compliance tasks.

AT 5. Establish a correspondence between a particular neuron function and the type of neuron that performs this function.

FUNCTIONS OF NEURONS TYPES OF NEURONS

1) transmit from one neuron A) sensitive,

on the other in the brain, B) intercalary,

2) transmit nerve impulses from organs B) motor.

feelings to the brain

3) transmit nerve impulses to muscles,

4) transmit nerve impulses from internal organs to the brain,

5) transmit nerve impulses to the glands.

AT 6. Establish a correspondence between the parts of the nervous system and their functions.

FUNCTIONS PERFORMED DEPARTMENT OF THE NERVOUS SYSTEM

1) constricts blood vessels, A) sympathetic,

2) slows down the rhythm of the heart, B) parasympathetic.

3) narrows the bronchi,

4) dilates the pupil.

AT 7. Establish a correspondence between the structure and functions of a neuron and its processes.

STRUCTURE AND FUNCTIONS OF THE NEURON PROCESS

1) conducts a signal to the neuron body, A) axon,

2) externally covered with a myelin sheath, B) dendrite.

3) short and highly branched,

4) participates in the formation of nerve fibers,

5) conducts the signal from the neuron body.

AT 8. Establish a correspondence between the properties of the nervous system and its types that have these properties.

PROPERTIES TYPE OF NERVOUS SYSTEM

1) innervates the skin and skeletal muscles, A) somatic,

2) innervates all internal organs, B) autonomic.

3) helps maintain body communication

with the external environment,

4) regulates metabolic processes, body growth,

5) actions are controlled by consciousness (voluntary),

6) actions are not subject to consciousness (autonomous).

AT 9. Establish a correspondence between examples of human nervous activity and the functions of the spinal cord.

EXAMPLES OF NERVOUS ACTIVITY SPINAL FUNCTION

1) knee reflex, A) reflex,

2) transmission of nerve impulses from the spinal cord B) conduction.

brain to brain,

3) extension of the limbs,

4) withdrawing the hand from a hot object,

5) transmission of nerve impulses from the brain

to the muscles of the limbs.

AT 10 O'CLOCK. Establish a correspondence between the structural feature and function of the brain and its department.

STRUCTURE FEATURES OF THE HEAD DEPARTMENTS
AND BRAIN FUNCTIONS

1) contains the respiratory center, A) medulla oblongata,

2) the surface is divided into lobes, B) the forebrain.

3) perceives and processes information from

sense organs,

4) regulates the activity of the cardiovascular system,

5) contains centers of the body’s defense reactions – cough

and sneezing.

Sequencing tasks.

AT 11. Establish the correct sequence of location of the parts of the brain stem, in the direction from the spinal cord.

A) diencephalon,

B) medulla oblongata,

B) midbrain

Free-response questions

The human nervous system consists of neurons that perform its main functions, as well as auxiliary cells that ensure their vital activity or performance. All nerve cells form special tissues located in the skull, the human spine in the form of organs of the brain or spinal cord, as well as throughout the body in the form of nerves - fibers from neurons that grow from one another, intertwining many times, forming a single neural network that penetrates into every even the smallest corner of the body.

Based on the structure and functions performed, it is customary to divide the entire nervous system into the central (CNS) and peripheral parts (PNS). The central one is represented by command and analysis centers, and the peripheral one is represented by an extensive network of neurons and their processes throughout the body.

The functions of the PNS are mostly executive, since its task is to convey information to the central nervous system from organs or receptors, transmit orders from the central nervous system to organs, muscles and glands, and also control the implementation of these orders.

The peripheral system, in turn, consists of two subsystems: somatic and vegetative. The functions of the somatic subsection are represented by the motor activity of skeletal and motor muscles, as well as sensory (collection and delivery of information from receptors). Somatic also maintains constant muscle tone of skeletal muscles. The vegetative system has more complex, rather managerial functions.

The functions of the ANS, unlike the somatic subdivision of the nervous system, do not consist in simply receiving or transmitting information from an organ to the brain and back, but in controlling the unconscious work of internal organs.

The autonomic nervous system regulates the activity of all internal organs, as well as from large to small glands, regulates the work of the muscles of hollow organs (heart, lungs, intestines, bladder, esophagus, stomach, etc.), and also by controlling the work of internal organs can regulate the entire metabolism and homeostasis of a person as a whole.

We can say that the ANS regulates the activities of the body, which it carries out unconsciously, without obeying reason.

Structure

The structure is not too different from the sympathetic one, since it is represented by the same nerves, ultimately leading to the spinal cord or directly to the brain.

Based on the functions performed by the neurons of the autonomic part of the peripheral system, it is conventionally divided into three subsections:

• The sympathetic section of the ANS is represented by nerves from neurons that excite the activity of the organ or transmit an exciting signal from special centers located in the central nervous system.
• The parasympathetic department is structured in exactly the same way, only instead of exciting signals it brings suppressive signals to the organ, thereby reducing the intensity of its activity.
• The metasympathetic subdivision of the autonomic department, which regulates the contraction of hollow organs, is its main difference from the somatic one and determines its certain independence from the central nervous system. It is built in the form of special microganglionic formations - sets of neurons located directly in the controlled organs, in the form of intramural ganglia - nerve nodes that control the contractility of the organ, as well as nerves connecting them to each other and to the rest of the human nervous system.

The activity of the metasymptic subdivision can be either independent or corrected by the somatic nervous system using reflex effects or hormonal influences, as well as partially by the central nervous system, which controls the endocrine system responsible for the production of hormones.

The neuronal fibers of the ANS intertwine and connect with the somatic nerves, and then transmit information to the central one through the main large nerves: spinal or cranial.

There is not a single large nerve that performs only autonomic or somatic functions; this division occurs at a smaller or, in general, cellular level.

Diseases to which she is susceptible

Although people divide the human nervous system into subsections, in fact it represents a special network, each part of which is closely connected with the others and depends on them, and not only exchanges information. Diseases of the autonomic part of the integral nervous system are diseases of the PNS as a whole and are represented by either neuritis or neuralgia.

• Neuralgia is an inflammatory process in the nerve, which does not lead to its destruction, but without treatment it can develop into neuritis.
• Neuritis is inflammation of a nerve or its injury, accompanied by the death of its cells or disruption of the integrity of the fiber.

Neuritis, in turn, is of the following types:

• Multineuritis, when many nerves are affected at once.
• Polyneuritis, the cause of which is pathology of several nerves.
• Mononeuritis is neuritis of only one nerve.

These diseases occur due to negative effects directly on nerve tissue caused by the following factors:

• Pinching or compression of the nerve by muscles, tissue tumors, neoplasms, overgrown ligaments or bones, aneurysms, etc.
• Nerve hypothermia.
• Injury to the nerve or nearby tissue.
• Infections.
• Diabetes.
• Toxic damage.
• Degenerative processes of nerve tissue, for example, multiple sclerosis.
• Lack of blood circulation.
• Lack of any substances, such as vitamins.
• Metabolic disorder.
• Irradiation.

At the same time, polyneuritis or multineuritis is usually caused by the last eight reasons.

In addition to neuritis and neuralgia, in the case of the ANS, a pathological imbalance in the work of its sympathetic department with the parasympathetic may be observed due to hereditary abnormalities, negative brain damage or due to immaturity of the brain, which is quite common in childhood, when the sympathetic and parasympathetic centers begin to take turns the top develops unevenly, which is the norm and goes away on its own with age.

Breakdowns of the centers of the metasympathetic nervous system occur extremely rarely.

Consequences of disruption

The consequences of disturbances in the functioning of the ANS are the improper performance of its functions in regulating the activity of internal organs, and as a consequence - a malfunction of their work, which at a minimum can be expressed in improper excretory activity by the secretory glands, for example, hypersalivation (salivation), sweating, or, conversely, lack of sweat, covering the skin with fat or lack of its production by the sebaceous glands. The consequences of disruption of the ANS lead to disruptions in the functioning of vital organs: the heart and respiratory organs, but this is extremely rare. Severe polyneuritis usually causes small complex deviations in the functioning of internal organs, resulting in a disruption of metabolism and physiological homeostasis.

It is the coordinated work of the sympathetic and parasympathetic divisions of the ANS that carries out the main work of regulation. Violation of the fragile balance occurs quite often for various reasons and leads to wear or, conversely, to oppression of any organ or their combination. In the case of glands that produce hormones, this can lead to not very unpleasant consequences.

Restoration of ANS functions

The neurons that make up the ANS are also unable to divide and regenerate the tissues that make up them, like the cells of other parts of the human nervous system. Treatment of neuralgia and neuritis is standard; it does not differ in the case of damage to the autonomic nerve fibers from damage to the somatic nerves of the human PNS.

Restoration of functions occurs according to the same principle as in any nervous tissue through the redistribution of responsibilities between neurons, as well as the growth of new processes by the remaining cells. Sometimes a permanent loss of any functions or their failure is possible; usually this does not lead to vital pathologies, but sometimes requires immediate intervention. Such an intervention includes suturing the damaged nerve or installing a heart pacemaker that regulates its contractions instead of the metasympathetic subdivision of the ANS.

The autonomic nervous system (ANS, ganglionic, visceral, organ, autonomic) is a complex mechanism that regulates the internal environment in the body.

The division of the brain into functional elements is described rather conventionally, since it is a complex, well-functioning mechanism. The ANS, on the one hand, coordinates the activity of its structures, and on the other, is influenced by the cortex.

General information about the ANS

The visceral system is responsible for performing many tasks. Higher nerve centers are responsible for the coordination of the ANS.

The neuron is the main structural unit of the ANS. The path along which the impulse signals travel is called a reflex arc. Neurons are necessary for conducting impulses from the spinal cord and brain to somatic organs, glands and smooth muscle tissue. An interesting fact is that the heart muscle is represented by striated tissue, but also contracts involuntarily. Thus, autonomic neurons regulate heart rate, secretion of endocrine and exocrine glands, peristaltic contractions of the intestine, and perform many other functions.

The ANS is divided into parasympathetic subsystems (SNS and PNS, respectively). They differ in the specificity of innervation and the nature of the reaction to substances that affect the ANS, but at the same time they closely interact with each other - both functionally and anatomically. Sympathy is stimulated by adrenaline, parasympathetic by acetylcholine. The former is inhibited by ergotamine, the latter by atropine.

Functions of the ANS in the human body

The tasks of the autonomous system include the regulation of all internal processes occurring in the body: the work of somatic organs, blood vessels, glands, muscles, and sensory organs.

The ANS maintains the stability of the human internal environment and the implementation of such vital functions as breathing, blood circulation, digestion, temperature regulation, metabolic processes, excretion, reproduction and others.

The ganglionic system participates in adaptation-trophic processes, that is, it regulates metabolism according to external conditions.

Thus, vegetative functions are as follows:

• support of homeostasis (constancy of the environment);
• adaptation of organs to various exogenous conditions (for example, in the cold, heat transfer decreases and heat production increases);
• vegetative implementation of human mental and physical activity.

Structure of the ANS (how it works)

Consideration of the structure of the ANS by levels:

Suprasegmental

It includes the hypothalamus, the reticular formation (waking and falling asleep), the visceral brain (behavioral reactions and emotions).

The hypothalamus is a small layer of brain matter. It has thirty-two pairs of nuclei that are responsible for neuroendocrine regulation and homeostasis. The hypothalamic region interacts with the cerebrospinal fluid circulation system because it is located next to the third ventricle and the subarachnoid space.

In this area of ​​the brain there is no glial layer between neurons and capillaries, which is why the hypothalamus immediately responds to changes in the chemical composition of the blood.

The hypothalamus interacts with the organs of the endocrine system by sending oxytocin and vasopressin, as well as releasing factors, to the pituitary gland. The visceral brain (psycho-emotional background during hormonal changes) and the cerebral cortex are connected to the hypothalamus.

So, the work of this important area is dependent on the cortex and subcortical structures. The hypothalamus is the highest center of the ANS, which regulates various types of metabolism, immune processes, and maintains environmental stability.

Segmental

Its elements are localized in the spinal segments and basal ganglia. This includes the SMN and PNS. Sympathy includes the Yakubovich nucleus (regulation of the muscles of the eye, constriction of the pupil), the nuclei of the ninth and tenth pairs of cranial nerves (the act of swallowing, providing nerve impulses to the cardiovascular and respiratory systems, gastrointestinal tract).

The parasympathetic system includes centers located in the sacral spinal cord (innervation of the genital and urinary organs, rectal area). Fibers emanate from the centers of this system and reach the target organs. This is how each specific organ is regulated.

The centers of the cervicothoracic region form the sympathetic part. Short fibers emerge from the nuclei of the gray matter and branch in the organs.

Thus, sympathetic irritation manifests itself everywhere - in different parts of the body. Acetylcholine is involved in sympathetic regulation, and adrenaline is involved in the periphery. Both subsystems interact with each other, but not always antagonistically (sweat glands are innervated only sympathetically).

Peripheral

It is represented by fibers entering the peripheral nerves and ending in organs and vessels. Particular attention is paid to the autonomic neuroregulation of the digestive system - an autonomous formation that regulates peristalsis, secretory function, etc.

Autonomic fibers, unlike the somatic system, lack a myelin sheath. Because of this, the speed of impulse transmission through them is 10 times less.

Sympathetic and parasympathetic

All organs are under the influence of these subsystems, except the sweat glands, blood vessels and the inner layer of the adrenal glands, which are innervated only sympathetically.

The parasympathetic structure is considered more ancient. It helps create stability in the functioning of organs and conditions for the formation of an energy reserve. The sympathetic department changes these states depending on the function performed.

Both departments interact closely. When certain conditions occur, one of them is activated, and the second is temporarily inhibited. If the tone of the parasympathetic department predominates, parasympathotonia occurs, and the tone of the sympathetic department - sympathotonia. The former is characterized by a state of sleep, the latter by heightened emotional reactions (anger, fear, etc.).

Command centers

Command centers are localized in the cortex, hypothalamus, brain stem and lateral spinal horns.

Peripheral sympathetic fibers arise from the lateral horns. The sympathetic trunk extends along the spinal column and unites twenty-four pairs of sympathetic nodes:

• three cervical;
• twelve breasts;
• five lumbar;
• four sacral.

The cells of the cervical ganglion form the nerve plexus of the carotid artery, the cells of the lower ganglion form the superior cardiac nerve. The thoracic nodes provide innervation to the aorta, bronchopulmonary system, and abdominal organs, while the lumbar nodes provide innervation to organs in the pelvis.

In the midbrain there is a mesencephalic section in which the nuclei of the cranial nerves are concentrated: the third pair is the Yakubovich nucleus (mydriasis), the central posterior nucleus (innervation of the ciliary muscle). The medulla oblongata is also called the bulbar region, the nerve fibers of which are responsible for the processes of salivation. Also here is the vegetative nucleus, which innervates the heart, bronchi, gastrointestinal tract and other organs.

Nerve cells of the sacral level innervate the genitourinary organs and the rectal gastrointestinal tract.

In addition to the listed structures, the fundamental system, the so-called “base” of the ANS, is distinguished - this is the hypothalamic-pituitary system, the cerebral cortex and the striatum. The hypothalamus is a kind of “conductor” that regulates all underlying structures and controls the functioning of the endocrine glands.

VNS Center

The leading regulatory link is the hypothalamus. Its nuclei communicate with the cortex of the telencephalon and the underlying parts of the brainstem.

Role of the hypothalamus:

• close relationship with all elements of the brain and spinal cord;
• implementation of neuroreflex and neurohumoral functions.

The hypothalamus is penetrated by a large number of vessels through which protein molecules penetrate well. Thus, this is a rather vulnerable area - against the background of any diseases of the central nervous system or organic damage, the work of the hypothalamus is easily disrupted.

The hypothalamic region regulates falling asleep and waking up, many metabolic processes, hormonal levels, the functioning of the heart and other organs.

Formation and development of the central nervous system

The brain is formed from the anterior wide part of the brain tube. Its posterior end transforms into the spinal cord as the fetus develops.

At the initial stage of formation, three brain vesicles are born with the help of constrictions:

• rhomboid - closer to the spinal cord;
• average;
• front.

The canal located inside the anterior part of the brain tube, as it develops, changes its shape, size and is modified into the cavity - the ventricles of the human brain.

Highlight:

• lateral ventricles - cavities of the telencephalon;
• 3rd ventricle – represented by the cavity of the diencephalon;
• – cavity of the midbrain;
• The 4th ventricle is the cavity of the hindbrain and medulla oblongata.

All ventricles are filled with cerebrospinal fluid.

ANS dysfunctions

When the VNS malfunctions, a variety of disorders are observed. Most pathological processes do not entail the loss of one or another function, but increased nervous excitability.

Problems in some parts of the ANS can spread to others. The specificity and severity of symptoms depend on the level affected.

Damage to the cortex leads to autonomic, psychoemotional disorders, and tissue nutritional disorders.

The reasons are varied: trauma, infections, toxic effects. Patients are restless, aggressive, exhausted, they experience increased sweating, fluctuations in heart rate and blood pressure.

When the limbic system is irritated, vegetative-visceral attacks appear (gastrointestinal, cardiovascular, etc.). Psycho-vegetative and emotional disorders develop: depression, anxiety, etc.

When the hypothalamic area is damaged (neoplasms, inflammation, toxic effects, injury, circulatory disorders), vegetative-trophic (sleep disorders, thermoregulatory function, stomach ulcers) and endocrine disorders develop.

Damage to the nodes of the sympathetic trunk leads to impaired sweating, hyperemia of the cervico-facial area, hoarseness or loss of voice, etc.

Dysfunction of the peripheral parts of the ANS often causes sympathalgia (painful sensations of various localizations). Patients complain of a burning or pressing nature of the pain, and there is often a tendency to spread.

Conditions may develop in which the functions of various organs are disrupted due to the activation of one part of the ANS and the inhibition of another. Parasympathotonia is accompanied by asthma, urticaria, runny nose, sympathotonia is accompanied by migraine, transient hypertension, and panic attacks.

Centrifugal nerve fibers are divided into somatic and autonomic.

Somatic nervous system conduct impulses to skeletal striated muscles, causing them to contract. The somatic nervous system communicates the body with the external environment: it perceives irritation, regulates the functioning of skeletal muscles and sensory organs, and provides a variety of movements in response to irritations perceived by the senses.

Autonomic nerve fibers are centrifugal and go to internal organs and systems, to all tissues of the body, forming autonomic nervous system.

The function of the autonomic nervous system is to regulate physiological processes in the body, to ensure the body's adaptation to changing environmental conditions. The centers of the autonomic nervous system are located in the middle, medulla oblongata and spinal cord, and the peripheral part consists of nerve ganglia and nerve fibers that innervate the working organ.

The autonomic nervous system consists of two parts: sympathetic and parasympathetic.

Sympathetic part of the autonomic nervous system is connected to the spinal cord, from the 1st thoracic to the 3rd lumbar vertebrae.

Parasympathetic part lies in the middle medulla oblongata of the brain and sacral spinal cord.

Most internal organs receive dual autonomic innervation, since they are approached by both sympathetic and parasympathetic nerve fibers, which function in close interaction, exerting the opposite effect on the organs. If the former, for example, enhance some activity, then the latter weaken it, as shown in the table.

The sympathetic nervous system enhances metabolism, increases the excitability of most tissues, and mobilizes the body's forces for vigorous activity. The parasympathetic nervous system helps restore spent energy reserves and regulates the body’s vital functions during sleep.

All activities of the autonomic (autonomic) nervous system are regulated by the subthalamic region - the hypothalamus of the diencephalon, which is connected to all parts of the central nervous system and to the endocrine glands.

Humoral regulation of body functions is the oldest form of chemical interaction between body cells, carried out by metabolic products that are carried by blood throughout the body and influence the activities of other cells, tissues, and organs.

The main factors of humoral regulation are biologically active substances - hormones, which are secreted by the endocrine glands (endocrine glands), which form the endocrine system in the body. The endocrine and nervous systems closely interact in regulatory activity, differing only in that the endocrine system controls processes that occur relatively slowly and over a long period of time. The nervous system controls rapid reactions whose duration can be measured in milliseconds.

Hormones are produced by special glands richly supplied with blood vessels. These glands do not have excretory ducts, and their hormones enter directly into the blood and are then distributed throughout the body, carrying out the humoral regulation of all functions: they stimulate or inhibit the activity of the body, affect its growth and development, and change the intensity of metabolism. Due to the absence of excretory ducts, these glands are called endocrine glands, or endocrine, in contrast to the digestive, sweat, and sebaceous glands of exocrine secretion, which have excretory ducts.

The endocrine glands include: pituitary gland, thyroid gland, parathyroid glands, suprarenal glands, pineal gland, islet part of the pancreas, endocrine part of the gonads.

The pituitary gland is a lower cerebral appendage, one of the central endocrine glands. The pituitary gland consists of three lobes: anterior, middle and posterior, surrounded by a common capsule of connective tissue.

One of the anterior lobe hormones affects growth. An excess of this hormone at a young age is accompanied by a sharp increase in growth - gigantism, and with increased function of the pituitary gland in an adult, when body growth stops, increased growth of short bones occurs: tarsus, metatarsus, phalanges of the fingers, as well as soft tissues (tongue, nose). This disease is called acromegaly. Increased function of the anterior pituitary gland leads to dwarfism. Pituitary dwarfs are proportionally built and have normal mental development. The anterior lobe of the pituitary gland also produces hormones that affect the metabolism of fats, proteins, and carbohydrates. The posterior lobe of the pituitary gland produces a hormone that reduces the rate of urine formation and changes water metabolism in the body.

The thyroid gland lies on top of the thyroid cartilage of the larynx and secretes hormones into the blood, which include iodine. Insufficient thyroid function in childhood retards growth, mental and sexual development, and the disease cretinism develops. In other periods, this leads to a decrease in metabolism, while nervous activity slows down, swelling develops, and signs of a serious disease called myxedema appear. Excessive activity of the thyroid gland leads to Graves' disease. The thyroid gland increases in volume and protrudes on the neck in the form of a goiter.

The pineal gland is small in size and located in the diencephalon. It has not been studied enough yet. It is assumed that pineal hormones inhibit the release of growth hormones by the pituitary gland. Her hormone is melatonin affects skin pigments.

The adrenal glands are paired glands located at the upper edge of the kidneys. Their weight is about 12 g each, together with the kidneys they are covered with a fat capsule. They distinguish between the cortical, lighter substance, and the cerebral, darker substance. They produce several hormones. Hormones are formed in the outer (cortical) layer - corticosteroids, influencing salt and carbohydrate metabolism, promoting the deposition of glycogen in liver cells and maintaining a constant concentration of glucose in the blood. With insufficient function of the cortical layer, Addison's disease develops, accompanied by muscle weakness, shortness of breath, loss of appetite, decreased concentration of sugar in the blood, and decreased body temperature. A characteristic sign of this disease is a bronze skin tone.

The hormone produced in the adrenal medulla is adrenalin. Its action is diverse: it increases the frequency and strength of heart contractions, increases blood pressure, enhances metabolism, especially carbohydrates, accelerates the conversion of liver glycogen and working muscles into glucose, as a result of which the performance of the mouse is restored.

The pancreas functions as a mixed gland. The pancreatic juice produced by it enters the duodenum through the excretory ducts and takes part in the process of breakdown of nutrients. This is an exocrine function. The intrasecretory function is performed by special cells (islets of Langerhans), which do not have excretory ducts and secrete hormones directly into the blood. One of them - insulin- converts excess glucose in the blood into animal starch glycogen and lowers blood sugar levels. Another hormone glucogen- acts on carbohydrate metabolism opposite to insulin. When it acts, the process of converting glycogen into glucose occurs. Disruption of the process of insulin formation in the pancreas causes a disease - diabetes mellitus.

The gonads are also mixed glands that produce sex hormones.

In the male gonads - testes- male reproductive cells develop - spermatozoa and male sex hormones (androgens, testosterone) are produced. In the female reproductive glands - ovaries- contains eggs that produce hormones (estrogens).

Under the influence of hormones secreted into the blood by the testes, the development of secondary sexual characteristics characteristic of the male body occurs (facial hair - beard, mustache, developed skeleton and muscles, low voice).

Hormones produced in the ovaries influence the formation of secondary sexual characteristics characteristic of the female body (lack of facial hair, thinner bones than a man’s, fat deposits under the skin, developed mammary glands, high-pitched voice).

The activity of all endocrine glands is interconnected: hormones of the anterior pituitary gland contribute to the development of the adrenal cortex, increase insulin secretion, affect the flow of thyroxine into the blood and the function of the gonads.

The work of all endocrine glands is regulated by the central nervous system, which contains a number of centers associated with the function of the glands. In turn, hormones influence the activity of the nervous system. Violation of the interaction of these two systems is accompanied by serious disorders of the functions of organs and the body as a whole.

Consequently, the interaction of the nervous and humoral systems should be considered as a single mechanism of neurohumoral regulation of functions that ensures the integrity of the human body.