Nervous and endocrine systems modulate functions immune system with the help of neurotransmitters, neuropeptides and hormones, and the immune system interacts with the neuroendocrine system with the help of cytokines, immunopeptides and immunotransmitters. There is a neurohormonal regulation of the immune response and functions of the immune system, mediated by the action of hormones and neuropeptides directly on immunocompetent cells or through the regulation of cytokine production (Fig. 2). Substances by axonal transport penetrate into the tissues they innervate and affect the processes of immunogenesis, and vice versa, the immune system receives signals (cytokines released by immunocompetent cells) that accelerate or slow down axonal transport, depending on the chemical nature of the influencing factor.
The nervous, endocrine and immune systems have much in common in their structure. All three systems act in concert, complementing and duplicating each other, significantly increasing the reliability of regulation of functions. They are closely interconnected and have a large number of cross paths. There is a certain parallel between lymphoid accumulations in various organs and tissues and autonomic ganglia. nervous system.
Stress and the immune system.
Animal experiments and clinical observations indicate that the state of stress, some mental disorders lead to a sharp inhibition of almost all parts of the body's immune system.
Most of the lymphoid tissues have a direct sympathetic innervation of both the blood vessels passing through the lymphoid tissue and the lymphocytes themselves. The autonomic nervous system directly innervates the parenchymal tissues of the thymus, spleen, lymph nodes, appendix and bone marrow.
The impact of pharmacological drugs on postganglionic adrenergic systems leads to the modulation of the immune system. Stress, on the contrary, leads to desensitization of β-adrenergic receptors.
Norepinephrine and epinephrine act on adrenoreceptors - AMP - protein kinase A inhibits the production of pro-inflammatory cytokines such as IL-12, tumor necrosis factor b (TNFa), interferon g (IFNg) by antigen-presenting cells and T-helpers of the first type and stimulates the production of anti-inflammatory cytokines such as IL-10 and transforming growth factor-b (TFRb).
Rice. 2. Two mechanisms of interference of immune processes in the activity of the nervous and endocrine systems: A - glucocorticoid feedback, inhibition of the synthesis of interleukin-1 and other lymphokines, B - autoantibodies to hormones and their receptors. Tx - T-helper, MF - macrophage
However, under certain conditions, catecholamines are able to limit the local immune response by inducing the formation of IL-1, TNFa and IL-8, protecting the body from the harmful effects of pro-inflammatory cytokines and other products of activated macrophages. When the sympathetic nervous system interacts with macrophages, neuropeptide Y acts as a signal co-transmitter from norepinephrine to macrophages. By blocking a-adrenergic receptors, it maintains the stimulating effect of endogenous noradrenaline through beta-adrenergic receptors.
Opioid peptides- one of the mediators between the central nervous system and the immune system. They are able to influence almost all immunological processes. In this regard, it has been suggested that opioid peptides indirectly modulate the secretion of pituitary hormones and thus affect the immune system.
Neurotransmitters and the immune system.
However, the relationship between the nervous and immune systems is not limited to the regulatory influence of the first on the second. AT last years a sufficient amount of data on the synthesis and secretion of neurotransmitters by cells of the immune system has accumulated.
Human peripheral blood T-lymphocytes contain L-dopa and norepinephrine, while B-cells contain only L-dopa.
Lymphocytes in vitro are able to synthesize norepinephrine from both L-tyrosine and L-dopa added to the culture medium at concentrations corresponding to the content in venous blood (5-10 -5 and 10 -8 mol, respectively), while D- dopa does not affect the intracellular content of norepinephrine. Therefore, human T-lymphocytes are able to synthesize catecholamines from their normal precursors at physiological concentrations.
The ratio of noradrenaline/adrenaline in peripheral blood lymphocytes is similar to that in plasma. There is a clear correlation between the amount of norepinephrine and adrenaline in lymphocytes, on the one hand, and cyclic AMP in them, on the other, both in normal conditions and during stimulation with isoproterenol.
Thymus gland (thymus).
The thymus is given an important place in the interaction of the immune system with the nervous and endocrine. There are several arguments in favor of this conclusion:
Insufficiency of the thymus not only slows down the formation of the immune system, but also leads to a violation of the embryonic development of the anterior pituitary gland;
Binding of hormones synthesized in pituitary acidophilic cells to receptors on thymus epithelial cells (TECs) increases their in vitro release of thymic peptides;
An increase in the concentration of glucocorticoids in the blood during stress causes atrophy of the thymus cortex due to the doubling of thymocytes undergoing apoptosis;
The thymus parenchyma is innervated by branches of the autonomic nervous system; the action of acetylcholine on acetylcholine receptors of thymus epithelial cells increases the protein-synthetic activity associated with the formation of thymic hormones.
Thymus proteins are a heterogeneous family of polypeptide hormones that not only have a regulatory effect on both the immune and endocrine systems, but are also under the control of the hypothalamic-pituitary-adrenal system and other endocrine glands. For example, thymulin production by the thymus regulates a number of hormones, including prolactin, growth hormone, and thyroid hormones. In turn, proteins isolated from the thymus regulate the secretion of hormones by the hypothalamic-pituitary-adrenal system and can directly affect the target glands of this system and gonadal tissues.
Regulation of the immune system.
The hypothalamic-pituitary-adrenal system is a powerful mechanism for regulating the immune system. Corticotropin-releasing factor, ACTH, β-melanocyte-stimulating hormone, β-endorphin are immunomodulators that affect both directly on lymphoid cells and through immunoregulatory hormones (glucocorticoids) and the nervous system.
The immune system sends signals to the neuroendocrine system through cytokines, the concentration of which in the blood reaches significant values during immune (inflammatory) reactions. IL-1, IL-6 and TNFa are the main cytokines causing profound neuroendocrine and metabolic changes in many organs and tissues.
Corticotropin-releasing factor acts as the main coordinator of reactions and is responsible for the activation of the ACTH-adrenal axis, temperature increase and CNS responses that determine sympathetic effects. An increase in ACTH secretion leads to an increase in the production of glucocorticoids and a-melanocyte-stimulating hormone - antagonists of cytokines and antipyretic hormones. The reaction of the sympathoadrenal system is associated with the accumulation of catecholamines in tissues.
The immune and endocrine systems cross-react using similar or identical ligands and receptors. Thus, cytokines and thymus hormones modulate the function of the hypothalamic-pituitary system.
* Interleukin (IL-l) directly regulates the production of corticotropin-releasing factor. Thymulin through adrenoglomerulotropin and the activity of hypothalamic neurons and pituitary cells increases the production of luteinizing hormone.
* Prolactin, acting on the receptors of lymphocytes, activates the synthesis and secretion of cytokines by cells. It acts on normal killer cells and induces their differentiation into prolactin-activated killer cells.
* Prolactin and growth hormone stimulate leukopoiesis (including lymphopoiesis).
Cells of the hypothalamus and pituitary gland can produce cytokines such as IL-1, IL-2, IL-6, g-interferon, b-transforming growth factor, and others. Accordingly, hormones including growth hormone, prolactin, luteinizing hormone, oxytocin, vasopressin, and somatostatin are produced in the thymus. Receptors for various cytokines and hormones have been identified both in the thymus and in the hypothalamic-pituitary axis.
The possible commonality of the regulatory mechanisms of the CNS, neuroendocrine and immunological systems put forward a new aspect of the homeostatic control of many pathological conditions (Fig. 3, 4). In maintaining homeostasis under the influence of various extreme factors on the body, all three systems act as a single whole, complementing each other. But, depending on the nature of the impact, one of them becomes the leading one in the regulation of adaptive and compensatory reactions.
Rice. 3. Interaction of the nervous, endocrine and immune systems in the regulation of the physiological functions of the body
Many functions of the immune system are provided by duplicating mechanisms, which are associated with additional reserve capabilities for protecting the body. The protective function of phagocytosis is duplicated by granulocytes and monocytes/macrophages. The ability to enhance phagocytosis is possessed by antibodies, the complement system and the cytokine g-interferon.
The cytotoxic effect against virus-infected or malignantly transformed target cells is duplicated by natural killers and cytotoxic T-lymphocytes (Fig. 5). In antiviral and antitumor immunity, either natural killer cells or cytotoxic T-lymphocytes can serve as protective effector cells.
Rice. 4. Interaction of the immune system and regulatory mechanisms with environmental factors under extreme conditions
Rice. 5. Duplication of functions in the immune system provides its reserve capabilities
With the development of inflammation, several synergistic cytokines duplicate the functions of each other, which made it possible to combine them into a group of pro-inflammatory cytokines (interleukins 1, 6, 8, 12, and TNFa). Other cytokines are involved in the final stage of inflammation, duplicating each other's effects. They serve as antagonists of pro-inflammatory cytokines and are called anti-inflammatory (interleukins 4, 10, 13 and transforming growth factor-b). Cytokines produced by Th2 (interleukins 4, 10, 13, transforming growth factor-b) are antagonistic to cytokines produced by Th1 (g-interferon, TNFa).
Ontogenetic changes in the immune system.
In the processes of ontogenesis, the immune system undergoes gradual development and maturation: relatively slow in the embryonic period, it accelerates sharply after the birth of a child due to the intake of a large number of foreign antigens into the body. However, most defense mechanisms bears features of immaturity throughout the entire period of childhood. Neurohormonal regulation of the functions of the immune system begins to clearly manifest itself in the puberty period. In adulthood, the immune system is characterized by the greatest ability to adapt when a person enters into changed and unfavorable environmental conditions. Aging of the body is accompanied by various manifestations of acquired insufficiency of the immune system.
The regulation of the activity of all systems and organs of our body is carried out by nervous system, which is a collection of nerve cells (neurons) equipped with processes.
Nervous system a person consists of a central part (the brain and spinal cord) and a peripheral part (nerves leaving the brain and spinal cord). Neurons communicate with each other through synapses.
In complex multicellular organisms, all the main forms of activity of the nervous system are associated with the participation of certain groups of nerve cells - nerve centers. These centers respond with appropriate reactions to external stimulation from the receptors associated with them. The activity of the central nervous system is characterized by the orderliness and consistency of reflex reactions, that is, their coordination.
At the heart of all the complex regulatory functions of the body is the interaction of two main nervous processes - excitation and inhibition.
According to the teachings of I. II. Pavlova, nervous system renders the following types effects on organs
–– launcher, causing or stopping the function of an organ (muscle contraction, gland secretion, etc.);
–– vasomotor, causing expansion or narrowing of blood vessels and thereby regulating the flow of blood to the organ (neurohumoral regulation),
–– trophic, which affects the metabolism (neuroendocrine regulation).
The regulation of the activity of internal organs is carried out by the nervous system through its special department - autonomic nervous system.
Together with central nervous system hormones are involved in providing emotional reactions and mental activity of a person.
Endocrine secretion contributes to the normal functioning of the immune and nervous systems, which in turn affect the work endocrine system(neuro-endocrine-immune regulation).
The close relationship between the functioning of the nervous and endocrine systems is explained by the presence of neurosecretory cells in the body. neurosecretion(from lat. secretio - separation) - the property of some nerve cells to produce and secrete special active products - neurohormones.
Spreading (like the hormones of the endocrine glands) throughout the body with blood flow, neurohormones capable of influencing the activity of various organs and systems. They regulate the functions of the endocrine glands, which, in turn, release hormones into the blood and regulate the activity of other organs.
neurosecretory cells, like the usual nerve cells, perceive signals coming to them from other parts of the nervous system, but then transmit the information received already in a humoral way (not through axons, but through vessels) - through neurohormones.
Thus, combining the properties of nerve and endocrine cells, neurosecretory cells combine nervous and endocrine regulatory mechanisms into a single neuroendocrine system. This ensures, in particular, the ability of the body to adapt to changing environmental conditions. The combination of nervous and endocrine mechanisms of regulation is carried out at the level of the hypothalamus and pituitary gland.
Fat metabolism
Fats are digested the fastest in the body, proteins are the slowest. The regulation of carbohydrate metabolism is mainly carried out by hormones and the central nervous system. Since everything in the body is interconnected, any disturbances in the functioning of one system cause corresponding changes in other systems and organs.
About the state fat metabolism may indirectly indicate blood sugar indicating the activity of carbohydrate metabolism. Normally, this figure is 70-120 mg%.
Regulation of fat metabolism
Regulation of fat metabolism carried out by the central nervous system, in particular the hypothalamus. The synthesis of fats in the tissues of the body occurs not only from the products of fat metabolism, but also from the products of carbohydrate and protein metabolism. Unlike carbohydrates, fats can be stored in the body in a concentrated form for a long time, so the excess amount of sugar that enters the body and is not immediately consumed by it for energy, turns into fat and is deposited in fat depots: a person develops obesity. More details about this disease will be discussed in the next section of this book.
The main part of food fat exposed digestion in upper intestines with the participation of the enzyme lipase, which is secreted by the pancreas and the gastric mucosa.
Norm lipases blood serum - 0.2-1.5 units. (less than 150 U/l). The content of lipase in the circulating blood increases with pancreatitis and some other diseases. With obesity, there is a decrease in the activity of tissue and plasma lipases.
Plays a leading role in metabolism liver which is both an endocrine and exocrine organ. It is in it that fatty acids are oxidized and cholesterol is produced, from which bile acids. Respectively, First of all, the level of cholesterol depends on the work of the liver.
bile, or cholic acids are end products of cholesterol metabolism. In my own way chemical composition these are steroids. They play an important role in the processes of digestion and absorption of fats, contribute to the growth and functioning of normal intestinal microflora.
Bile acids are part of the bile and excreted by the liver into the lumen of the small intestine. Together with bile acids, a small amount of free cholesterol is released into the small intestine, which is partially excreted in the feces, and the rest is dissolved and, together with bile acids and phospholipids, is absorbed in the small intestine.
The endocrine products of the liver are metabolites - glucose, which is necessary, in particular, for brain metabolism and the normal functioning of the nervous system, and triacylglycerides.
Processes fat metabolism in the liver and adipose tissue are inextricably linked. Free cholesterol in the body inhibits its own biosynthesis by the feedback principle. The rate of conversion of cholesterol into bile acids is proportional to its concentration in the blood, and also depends on the activity of the corresponding enzymes. The transport and storage of cholesterol is controlled by various mechanisms. The transport form of cholesterol is, as noted earlier, lipothyroidism.
CHAPTER 1. INTERACTION OF THE NERVOUS AND ENDOCRINE SYSTEM
The human body consists of cells that combine into tissues and systems - all this as a whole is a single supersystem of the body. Myriads of cellular elements would not be able to work as a whole, if the body did not have a complex mechanism of regulation. A special role in the regulation is played by the nervous system and the system of endocrine glands. The nature of the processes occurring in the central nervous system is largely determined by the state of endocrine regulation. So androgens and estrogens form the sexual instinct, many behavioral reactions. Obviously, neurons, just like other cells in our body, are under the control of the humoral regulatory system. The nervous system, evolutionarily later, has both control and subordinate connections with the endocrine system. These two regulatory systems complement each other, form a functionally unified mechanism, which ensures the high efficiency of neurohumoral regulation, puts it at the head of systems that coordinate all life processes in a multicellular organism. The regulation of the constancy of the internal environment of the body, which occurs according to the feedback principle, is very effective for maintaining homeostasis, but cannot fulfill all the tasks of adapting the body. For example, the adrenal cortex produces steroid hormones in response to hunger, illness, emotional arousal, and so on. So that the endocrine system can "respond" to light, sounds, smells, emotions, etc. there must be a connection between the endocrine glands and the nervous system.
1.1 a brief description of systems
The autonomic nervous system permeates our entire body like the thinnest web. It has two branches: excitation and inhibition. The sympathetic nervous system is the excitatory part, it puts us in a state of readiness to face challenge or danger. Nerve endings secrete neurotransmitters that stimulate the adrenal glands to release strong hormones - adrenaline and norepinephrine. They in turn increase the heart rate and respiratory rate, and act on the digestion process through the release of acid in the stomach. This creates a sucking sensation in the stomach. Parasympathetic nerve endings secrete other mediators that reduce the pulse and respiratory rate. Parasympathetic responses are relaxation and balance.
The endocrine system of the human body combines small in size and different in structure and functions of the endocrine glands that are part of the endocrine system. These are the pituitary gland with its independently functioning anterior and posterior lobes, the sex glands, the thyroid and parathyroid glands, the adrenal cortex and medulla, the pancreatic islet cells, and the secretory cells that line the intestinal tract. Taken together, they weigh no more than 100 grams, and the amount of hormones they produce can be calculated in billionths of a gram. And, nevertheless, the sphere of influence of hormones is exceptionally large. They have a direct impact on the growth and development of the body, on all types of metabolism, on puberty. There are no direct anatomical connections between the endocrine glands, but there is an interdependence of the functions of one gland from others. The endocrine system of a healthy person can be compared to a well-played orchestra, in which each gland confidently and subtly leads its part. And the main supreme endocrine gland, the pituitary gland, acts as a conductor. The anterior pituitary gland secretes six tropic hormones into the blood: somatotropic, adrenocorticotropic, thyrotropic, prolactin, follicle-stimulating and luteinizing - they direct and regulate the activity of other endocrine glands.
1.2 Interaction of the endocrine and nervous system
The pituitary gland can receive signals about what is happening in the body, but it has no direct connection with the external environment. Meanwhile, in order for the factors of the external environment not to constantly disrupt the vital activity of the organism, the adaptation of the body to changing external conditions must be carried out. The body learns about external influences through the sense organs, which transmit the received information to the central nervous system. Being the supreme gland of the endocrine system, the pituitary gland itself obeys the central nervous system and in particular the hypothalamus. This higher vegetative center constantly coordinates and regulates the activity of various parts of the brain and all internal organs. Heart rate, blood vessel tone, body temperature, the amount of water in the blood and tissues, the accumulation or consumption of proteins, fats, carbohydrates, mineral salts - in a word, the existence of our body, the constancy of its internal environment is under the control of the hypothalamus. Most of the nervous and humoral pathways of regulation converge at the level of the hypothalamus and due to this, a single neuroendocrine regulatory system is formed in the body. Axons of neurons located in the cerebral cortex and subcortical formations approach the cells of the hypothalamus. These axons secrete various neurotransmitters that have both activating and inhibitory effects on the secretory activity of the hypothalamus. The hypothalamus “turns” the nerve impulses coming from the brain into endocrine stimuli, which can be strengthened or weakened depending on the humoral signals coming to the hypothalamus from the glands and tissues subordinate to it.
The hypothalamus controls the pituitary gland using both nerve connections and the blood vessel system. The blood that enters the anterior pituitary gland necessarily passes through the median eminence of the hypothalamus and is enriched there with hypothalamic neurohormones. Neurohormones are substances of a peptide nature, which are parts of protein molecules. To date, seven neurohormones, the so-called liberins (that is, liberators), have been discovered that stimulate the synthesis of tropic hormones in the pituitary gland. And three neurohormones - prolactostatin, melanostatin and somatostatin - on the contrary, inhibit their production. Other neurohormones include vasopressin and oxytocin. Oxytocin stimulates the contraction of the smooth muscles of the uterus during childbirth, the production of milk by the mammary glands. Vasopressin is actively involved in the regulation of the transport of water and salts through cell membranes, under its influence, the lumen of blood vessels decreases and, consequently, blood pressure rises. Due to the fact that this hormone has the ability to retain water in the body, it is often called antidiuretic hormone (ADH). The main point of application of ADH is the renal tubules, where it stimulates the reabsorption of water from the primary urine into the blood. Neurohormones are produced by the nerve cells of the nuclei of the hypothalamus, and then they are transported along their own axons (nerve processes) to the posterior lobe of the pituitary gland, and from here these hormones enter the bloodstream, having a complex effect on the body systems.
Tropins formed in the pituitary gland not only regulate the activity of subordinate glands, but also perform independent endocrine functions. For example, prolactin has a lactogenic effect, and also inhibits the processes of cell differentiation, increases the sensitivity of the sex glands to gonadotropins, and stimulates parental instinct. Corticotropin is not only a stimulator of sterdogenesis, but also an activator of lipolysis in adipose tissue, as well as an important participant in the process of converting short-term memory into long-term memory in the brain. Growth hormone can stimulate the activity of the immune system, the metabolism of lipids, sugars, etc. Also, some hormones of the hypothalamus and pituitary gland can be formed not only in these tissues. For example, somatostatin (a hypothalamic hormone that inhibits the formation and secretion of growth hormone) is also found in the pancreas, where it inhibits the secretion of insulin and glucagon. Some substances act in both systems; they can be both hormones (i.e. products of the endocrine glands) and mediators (products of certain neurons). This dual role is played by norepinephrine, somatostatin, vasopressin, and oxytocin, as well as transmitters of the diffuse intestinal nervous system, such as cholecystokinin and vasoactive intestinal polypeptide.
However, one should not think that the hypothalamus and pituitary gland only give orders, lowering the "guiding" hormones along the chain. They themselves sensitively analyze the signals coming from the periphery, from the endocrine glands. The activity of the endocrine system is carried out on the basis of the universal principle of feedback. An excess of hormones of one or another endocrine gland inhibits the release of a specific pituitary hormone responsible for the work of this gland, and a deficiency induces the pituitary gland to increase the production of the corresponding triple hormone. The mechanism of interaction between the neurohormones of the hypothalamus, the triple hormones of the pituitary gland and the hormones of the peripheral endocrine glands in a healthy body has been worked out by a long evolutionary development and is very reliable. However, a failure in one link of this complex chain is enough to cause a violation of quantitative, and sometimes even qualitative, relationships in the whole system, resulting in various endocrine diseases.
CHAPTER 2. BASIC FUNCTIONS OF THE THALAMUS
... - neuroendocrinology - studies the interaction of the nervous system and endocrine glands in the regulation of body functions. Clinical endocrinology as a branch of clinical medicine studies diseases of the endocrine system (their epidemiology, etiology, pathogenesis, clinic, treatment and prevention), as well as changes in the endocrine glands in other diseases. Modern methods research allows...
Leptospirosis, etc.) and secondary (vertebrogenic, after childhood exanthemic infections, infectious mononucleosis, with periarteritis nodosa, rheumatism, etc.). According to the pathogenesis and pathomorphology, diseases of the peripheral nervous system are divided into neuritis (radiculitis), neuropathy (radiculopathy) and neuralgia. Neuritis (radiculitis) - inflammation of the peripheral nerves and roots. The nature...
The endocrine system, together with the nervous system, have a regulatory effect on all other organs and systems of the body, forcing it to function as a single system.
The endocrine system includes glands that do not have excretory ducts, but release highly active biological substances into the internal environment of the body, acting on cells, tissues and organs of substances (hormones), stimulating or weakening their functions.
Cells in which the production of hormones becomes the main or predominant function are called endocrine. In the human body, the endocrine system is represented by the secretory nuclei of the hypothalamus, pituitary, epiphysis, thyroid, parathyroid glands, adrenal glands, endocrine parts of the sex and pancreas, as well as individual glandular cells scattered in other (non-endocrine) organs or tissues.
With the help of hormones secreted by the endocrine system, the body functions are regulated and coordinated and brought into line with its needs, as well as with irritations received from the external and internal environment.
By chemical nature, most hormones belong to proteins - proteins or glycoproteins. Other hormones are derivatives of amino acids (tyrosine) or steroids. Many hormones, entering the bloodstream, bind to serum proteins and are transported throughout the body in the form of such complexes. The connection of the hormone with the carrier protein, although it protects the hormone from premature degradation, but weakens its activity. The release of the hormone from the carrier occurs in the cells of the organ that perceives this hormone.
Since hormones are released into the blood stream, a plentiful blood supply to the endocrine glands is an indispensable condition for their functioning. Each hormone acts only on those target cells that have specific chemical receptors in their plasma membranes.
The target organs, usually classified as non-endocrine, include the kidney, in the juxtaglomerular complex of which renin is produced; salivary and prostate, in which special cells are found that produce a factor that stimulates the growth of nerves; as well as special cells (enterinocytes) localized in the mucous membrane of the gastrointestinal tract and producing a number of enteric (intestinal) hormones. Many hormones (including endorphins and enkephalins), which have a wide spectrum of action, are produced in the brain.
Relationship between the nervous and endocrine systems
The nervous system, sending its efferent impulses along the nerve fibers directly to the innervated organ, causes directed local reactions that come on quickly and stop just as quickly.
Hormonal distant influences play a predominant role in the regulation of such common functions organism, such as metabolism, somatic growth, reproductive functions. The joint participation of the nervous and endocrine systems in ensuring the regulation and coordination of body functions is determined by the fact that the regulatory influences exerted by both the nervous and endocrine systems are implemented by fundamentally the same mechanisms.
At the same time, all nerve cells exhibit the ability to synthesize protein substances, as evidenced by the strong development of the granular endoplasmic reticulum and the abundance of ribonucleoproteins in their perikarya. The axons of such neurons, as a rule, end in capillaries, and the synthesized products accumulated in the terminals are released into the blood, with the current of which they are carried throughout the body and, unlike mediators, have not a local, but a distant regulatory effect, similar to the hormones of the endocrine glands. Such nerve cells are called neurosecretory, and the products produced and secreted by them are called neurohormones. Neurosecretory cells, perceiving, like any neurocyte, afferent signals from other parts of the nervous system, send their efferent impulses through the blood, that is, humorally (like endocrine cells). Therefore, neurosecretory cells, physiologically occupying an intermediate position between nervous and endocrine cells, unite the nervous and endocrine systems into a single neuroendocrine system and thus act as neuroendocrine transmitters (switches).
In recent years, it has been established that the nervous system contains peptidergic neurons, which, in addition to mediators, secrete a number of hormones that can modulate the secretory activity of the endocrine glands. Therefore, as noted above, the nervous and endocrine systems act as a single regulatory neuroendocrine system.
Classification of the endocrine glands
At the beginning of the development of endocrinology as a science, endocrine glands were grouped according to their origin from one or another embryonic rudiment of the germ layers. However, further expansion of knowledge about the role of endocrine functions in the body showed that the commonality or proximity of embryonic anlages does not at all prejudge the joint participation of the glands developing from such rudiments in the regulation of body functions.
Neurons are the building blocks for the human "message system", there are entire networks of neurons that transmit signals between the brain and the body. These organized networks, which include more than a trillion neurons, create the so-called nervous system. It consists of two parts: the central nervous system (the brain and spinal cord) and the peripheral (nerves and nerve networks throughout the body)
Endocrine system part of the body's information transmission system. Uses glands throughout the body that regulate many processes such as metabolism, digestion, blood pressure, and growth. Among the most important endocrine glands are the pineal gland, hypothalamus, pituitary gland, thyroid gland, ovaries and testicles.
central nervous system(CNS) consists of the brain and spinal cord.
Peripheral nervous system(PNS) consists of nerves that extend beyond the central nervous system. The PNS can be further divided into two different nervous systems: somatic and vegetative.
somatic nervous system: The somatic nervous system transmits physical sensations and commands to movements and actions.
autonomic nervous system: The autonomic nervous system controls involuntary functions such as heartbeat, respiration, digestion and blood pressure. This system is also associated with emotional responses such as sweating and crying.
10. Lower and higher nervous activity.
Lower nervous activity (NND) - directed to the internal environment of the body. This is a set of neurophysiological processes that ensure the implementation of unconditioned reflexes and instincts. This is the activity of the Spinal Cord and the brain stem, which ensures the regulation of the activity of internal organs and their interconnection, thanks to which the body functions as a single whole.
Higher nervous activity (HNI) - directed towards the external environment. This is a set of neurophysiological processes that provide conscious and subconscious processing of information, assimilation of information, adaptive behavior to the environment and ontogeny training in all types of activities, including purposeful behavior in society.
11. Physiology of adaptation and stress.
Adaptation Syndrome:
The first is called the anxiety stage. This stage is associated with the mobilization of the body's defense mechanisms, an increase in the level of adrenaline in the blood.
The next stage is called the stage of resistance or resistance. This stage is distinguished by the highest level of body resistance to the action of harmful factors, which reflects the ability to maintain the state of homeostasis.
If the impact of the stressor continues, then as a result, the “energy of adaptation”, i.e. the adaptive mechanisms involved in maintaining the resistance stage will exhaust themselves. Then the organism enters the final stage - the stage of exhaustion, when the survival of the organism may be threatened.
The human body deals with stress in the following ways:
1. Stressors are analyzed in the higher parts of the cerebral cortex, after which certain signals are sent to the muscles responsible for movement, preparing the body to respond to the stressor.
2. The stressor also affects the autonomic nervous system. The pulse quickens, blood pressure rises, the level of erythrocytes and blood sugar rises, breathing becomes frequent and intermittent. This increases the amount of oxygen supplied to the tissues. The person is ready to fight or flee.
3. From the analyzer sections of the cortex, signals enter the hypothalamus and adrenal glands. The adrenal glands regulate the release of adrenaline into the blood, which is a common fast-acting stimulant.
