Central nervous system (CNS) is the main part of the nervous system of animals and humans, consisting of neurons and their processes; It is represented in invertebrates by a system of closely interconnected nerve nodes (ganglia), in vertebrates and humans by the spinal cord and brain.

The body must receive and evaluate information about the state of the external and internal environment and, taking into account urgent needs, build behavioral programs. This function is performed by the nervous system, which, in the words of I.P. Pavlov, is “an inexpressibly complex and subtle instrument of communication, the connection of numerous parts of the body with each other and the body as a highly complex system with an infinite number of external influences.”

Thus, the most important functions of the nervous system include: Integrative function 1. Integrative function - controlling the work of all organs and systems and ensuring the functional unity of the body. The body responds to any impact as a single whole, measuring and subordinating the needs and capabilities of different organs and systems.

Sensory function 2. Sensory function - receiving information about the state of the external and internal environment from special perceiving cells or the endings of neurons - receptors. Reflection function memory function 3. Reflection function, including mental, and memory function - processing, evaluation, storage, reproduction and forgetting of received information.

Behavior programming 4. Behavior programming. Based on incoming and already stored information, the nervous system either builds new programs for interaction with the environment, or selects the most suitable of the existing programs. In the latter case, species-specific programs that are genetically embedded can be used

Central nervous system with the brain and spinal cord The central nervous system (systema nervosum centrale) is represented by the brain and spinal cord. In their thickness, areas of gray color (gray matter) are clearly visible, this is the appearance of clusters of neuron bodies, and white matter, formed by the processes of nerve cells, through which they establish connections with each other. The number of neurons and the degree of their concentration are much higher in the upper section, which as a result takes on the appearance of a three-dimensional brain

Central nervous system (CNS) I. Cervical nerves. II. Thoracic nerves. III. Lumbar nerves\\\. IV. Sacral nerves. V. Coccygeal nerves. -/- 1. Brain. 2. Diencephalon. 3. Midbrain. 4. Bridge. 5. Cerebellum. 6. Medulla oblongata. 7. Spinal cord. 8. Cervical thickening. 9. Transverse thickening. 10. "Ponytail"

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

Structural and functional characteristics of the cerebral cortex The cerebral cortex is a multilayer neural tissue with many folds with a total area in both hemispheres of approximately 2200 cm2, which corresponds to a square with sides of 47 x 47 cm, its volume corresponds to 40% of the mass of the brain, its thickness varies from 1.3 to 4.5 mm, and the total volume is 600 cm 3. The cerebral cortex includes 10 9 –10 10 neurons and many glial cells, the total number of which is still unknown. The cortex has 6 layers (I–VI)

Semi-schematic image of the layers of the cerebral cortex (according to K. Brodmann, Vogt; with modifications): a – the main types of nerve cells (Golgi staining); b – cell bodies of neurons (Nissl staining); c – general arrangement of fibers (myelin sheaths). In layers I–IV, the perception and processing of Signals entering the cortex in the form of nerve impulses occurs. The efferent pathways leaving the cortex are formed mainly in layers V–VI.

The integrating role of the central nervous system (CNS) is the subordination and unification of tissues and organs into a central-peripheral system, the activity of which is aimed at achieving an adaptive result useful for the body. This unification becomes possible thanks to the participation of the central nervous system: in the control of the musculoskeletal system with the help of the somatic nervous system, regulation of the functions of all tissues and internal organs with the help of the autonomic nervous and endocrine systems, the presence of extensive afferent connections of the central nervous system with all somatic and autonomic effectors.

The main functions of the central nervous system are: 1) regulation of the activity of all tissues and organs and combining them into a single whole; 2) ensuring the adaptation of the body to environmental conditions (organization of adequate behavior in accordance with the needs of the body).

Levels of integration of the central nervous system The first level is the neuron. Thanks to the many excitatory and inhibitory synapses on a neuron, it has evolved into a decisive device. The interaction of excitatory and inhibitory inputs and subsynaptic neurochemical processes ultimately determine whether a command will be given to another neuron or working organ or not. The second level is a neuronal ensemble (module), which has qualitatively new properties that are absent in individual neurons, allowing it to be included in more complex types of CNS reactions

Levels of integration of the central nervous system (continued) The third level is the nerve center. Due to the presence of multiple direct, feedback and reciprocal connections in the central nervous system, the presence of direct and feedback connections with peripheral organs, nerve centers often act as autonomous command devices that implement the control of one or another process on the periphery in the body as a self-regulating, self-healing, self-reproducing system. The fourth level is the highest, uniting all regulatory centers into a single regulatory system, and individual organs and systems into a single physiological system - the body. This is achieved by the interaction of the main systems of the central nervous system: the limbic, reticular formation, subcortical formations and neocortex - as the highest department of the central nervous system, organizing behavioral reactions and their autonomic support.

The organism is a complex hierarchy (i.e., interconnection and intersubordination) of systems that make up the levels of its organization: molecular, subcellular, cellular, tissue, organ, systemic and organismal. The organism is a self-organizing system. The body itself selects and maintains the values ​​of a huge number of parameters, changes them depending on needs, which allows it to ensure the most optimal functioning. For example, at low environmental temperatures, the body reduces body surface temperature (to reduce heat transfer), increases the rate of oxidative processes in internal organs and muscle activity (to increase heat generation). A person insulates his home, changes his clothes (to increase the heat-insulating properties), and even does this in advance, proactively responding to changes in the external environment.

The basis of physiological regulation is the transmission and processing of information. The term “information” should be understood as everything that reflects facts or events that have occurred, are occurring or may occur. Information processing is carried out by a control system or regulation system. It consists of individual elements connected by information channels.

Three levels of structural organization of the regulatory system control device (central nervous system); input and output communication channels (nerves, internal fluids with information molecules of substances); sensors that perceive information at the input of the system (sensory receptors); formations located on the executive organs (cells) and receiving information from the output channels (cellular receptors). The part of the control device used to store information is called a storage device or memory apparatus.

The nervous system is one, but it is conventionally divided into parts. There are two classifications: according to the topographic principle, i.e., according to the location of the nervous system in the human body, and according to the functional principle, i.e., according to the areas of its innervation. According to topographical principles, the nervous system is divided into central and peripheral. The central nervous system includes the brain and spinal cord, and the peripheral nervous system includes nerves that arise from the brain (12 pairs of cranial nerves) and nerves that arise from the spinal cord (31 pairs of spinal nerves).

According to the functional principle, the nervous system is divided into a somatic part and an autonomous, or autonomic, part. The somatic part of the nervous system innervates the striated muscles of the skeleton and some organs - tongue, pharynx, larynx, etc., and also provides sensitive innervation to the entire body.

The autonomic part of the nervous system innervates all the smooth muscles of the body, providing motor and secretory innervation of internal organs, motor innervation of the cardiovascular system and trophic innervation of striated muscles. The autonomic nervous system, in turn, is divided into two divisions: sympathetic and parasympathetic. The somatic and autonomic parts of the nervous system are closely interconnected, forming one whole.

Feedback channel Regulation by deviation requires a communication channel between the output of the regulation system and its central control apparatus, and even between the output and input of the regulation system. This channel is called feedback. In essence, feedback is the process of influencing the result of an action on the cause and mechanism of this action. It is feedback that allows deviation regulation to operate in two modes: compensation and tracking. The compensation mode provides quick correction of the mismatch between the real and optimal state of physiological systems under sudden environmental influences, i.e. optimizes the body's reactions. In the tracking mode, regulation is carried out according to predetermined programs, and feedback controls the compliance of the parameters of the physiological system with the given program. If a deviation occurs, a compensation mode is implemented.

Ways to control the launch (initiation) of physiological processes in the body. It is a control process that causes a transition of organ function from a state of relative rest to an active state or from active activity to a state of rest. For example, under certain conditions, the central nervous system initiates the work of the digestive glands, phasic contractions of skeletal muscles, urinary processes, defecation, etc. Correction of physiological processes. Allows you to control the activity of an organ that performs a physiological function automatically or initiated by the receipt of control signals. An example is the correction of the functioning of the heart by the central nervous system through influences transmitted through the vagus and sympathetic nerves. coordination of physiological processes. Provides for the coordination of the work of several organs or systems simultaneously to obtain a useful adaptive result. For example, to carry out the act of walking upright, it is necessary to coordinate the work of muscles and centers that ensure the movement of the lower extremities in space, a shift in the center of gravity of the body, and a change in the tone of skeletal muscles.

The mechanisms of regulation (control) of the body’s vital functions are usually divided into nervous and humoral. The nervous mechanism involves changes in physiological functions under the influence of control influences transmitted from the central nervous system along nerve fibers to the organs and systems of the body. The nervous mechanism is a later product of evolution compared to the humoral one; it is more complex and more perfect. It is characterized by high speed of propagation and accurate transfer of control actions to the control object, and high reliability of communication. Nervous regulation ensures fast and targeted transmission of signals, which in the form of nerve impulses along the appropriate nerve conductors arrive at a specific recipient, the object of regulation

Humoral regulatory mechanisms use the liquid internal environment to transmit information using chemical molecules. Humoral regulation is carried out with the help of chemical molecules secreted by cells or specialized tissues and organs. The humoral control mechanism is the oldest form of interaction between cells, organs and systems, therefore, in the human body and higher animals one can find various variants of the humoral regulatory mechanism, reflecting to a certain extent its evolution. For example, under the influence of CO 2 formed in tissues as a result of oxygen utilization, the activity of the respiratory center and, as a consequence, the depth and frequency of breathing changes. Under the influence of adrenaline released into the blood from the adrenal glands, the frequency and strength of heart contractions, the tone of peripheral vessels, a number of functions of the central nervous system, the intensity of metabolic processes in skeletal muscles change, and the coagulation properties of the blood increase.

Humoral regulation is divided into local, unspecialized self-regulation, and a highly specialized system of hormonal regulation, which provides generalized effects with the help of hormones. Local humoral regulation (tissue self-regulation) is practically not controlled by the nervous system, while the hormonal regulation system is part of a single neuro-humoral system.

The interaction of the humoral and nervous mechanisms creates an integrative control option that can ensure an adequate change in functions from the cellular to the organismal levels when the external and internal environment changes. The humoral mechanism uses chemicals, metabolic products, prostaglandins, regulatory peptides, hormones, etc. as means of control and transmission of information. Thus, the accumulation of lactic acid in muscles during physical activity is a source of information about a lack of oxygen

The division of the mechanisms of regulation of the body's vital functions into nervous and humoral is very arbitrary and can only be used for analytical purposes as a method of study. In fact, nervous and humoral regulatory mechanisms are inseparable. information about the state of the external and internal environment is almost always perceived by elements of the nervous system (receptors); signals arriving through the control channels of the nervous system are transmitted at the ends of nerve conductors in the form of chemical intermediary molecules entering the microenvironment of cells, i.e. humoral way. And the endocrine glands, specialized for humoral regulation, are controlled by the nervous system. The neurohumoral system for regulating physiological functions is one.

Neurons The nervous system consists of neurons, or nerve cells, and neuroglia, or neuroglial cells. Neurons are the main structural and functional elements in both the central and peripheral nervous systems. Neurons are excitable cells, meaning they are capable of generating and transmitting electrical impulses (action potentials). Neurons have different shapes and sizes and form two types of processes: axons and dendrites. A neuron usually has several short branched dendrites, along which impulses travel to the neuron body, and one long axon, along which impulses travel from the neuron body to other cells (neurons, muscle or glandular cells). The transfer of excitation from one neuron to other cells occurs through specialized contacts of synapses. neurons, neuroglia, and synapse action potentials

Neurons consist of a cell body with a diameter of 3–100 µm, containing the nucleus and organelles, and cytoplasmic processes. Short processes that conduct impulses to the cell body are called dendrites; longer (up to several meters) and thin processes that conduct impulses from the cell body to other cells are called axons. Axons connect to neighboring neurons at synapses

Neuroglia Neuroglia cells are concentrated in the central nervous system, where they are ten times more numerous than neurons. They fill the space between neurons, providing them with nutrients. Perhaps neurolgia cells are involved in storing information in the form of RNA codes. When damaged, neurolgia cells actively divide, forming a scar at the site of damage; neurolgia cells of another type turn into phagocytes and protect the body from viruses and bacteria.

Synapses The transfer of information from one neuron to another occurs at synapses. Typically, the axon of one neuron and the dendrites or body of another are connected through synapses. The endings of muscle fibers are also connected to neurons by synapses. The number of synapses is very large: some brain cells can have up to synapses. At most synapses, the signal is transmitted chemically. The nerve endings are separated from each other by a synaptic cleft about 20 nm wide. Nerve endings have thickenings called synaptic plaques; the cytoplasm of these thickenings contains numerous synaptic vesicles with a diameter of about 50 nm, inside of which there is a mediator - a substance with the help of which a nerve signal is transmitted through the synapse. The arrival of a nerve impulse causes the vesicle to merge with the membrane and the release of the transmitter from the cell. After about 0.5 ms, the transmitter molecules enter the membrane of the second nerve cell, where they bind to receptor molecules and transmit the signal further.

The conduction pathways of the central nervous system, or tracts of the brain and spinal cord, are usually called collections of nerve fibers (systems of fiber bundles) that connect various structures of one or different levels of the hierarchy of structures of the nervous system: brain structures, spinal cord structures, as well as brain structures with structures spinal cord. central nervous system of the brain spinal cord collection of nerve fibers system levels structure hierarchy of the nervous system A set of neuron circuits homogeneous in their characteristics (origin, structure and functions) is called a tract. homogeneous characteristics functions

Conducting pathways serve to achieve four main goals: 1. To interconnect sets of neurons (nerve centers) of the same or different levels of the nervous system; 2. To transmit afferent information to the regulators of the nervous system (to the nerve centers); 3. To generate control signals. The name “conducting pathways” does not mean that these pathways serve exclusively to conduct afferent or efferent information, similar to the conduction of electric current in the simplest electrical circuits. Chains of neurons - pathways are essentially hierarchically interacting elements of the system regulator. It is in these hierarchical chains, as elements of regulators, and not just at the end points of paths (for example, in the cerebral cortex), that information is processed and control signals are generated for control objects of body systems. 4. To transmit control signals from nervous system regulators to control objects - organs and organ systems. Thus, the initially purely anatomical concept of “path”, or collective - “path”, “tract” also has a physiological meaning and is closely related to such physiological concepts as control system, inputs, regulator, outputs. organism control signals control objects organs organ systems anatomical concept physiological meaning control system inputs regulator outputs

Both in the brain and in the spinal cord, three groups of pathways are distinguished: associative pathways, composed of associative nerve fibers, commissural pathways, composed of commissural nerve fibers, and projection pathways, composed of projection nerve fibers. associative pathways, commissural pathways, projection pathways. Association nerve fibers connect areas of gray matter, various nuclei and nerve centers within one half of the brain. Commissural (commissural) nerve fibers connect the nerve centers of the right and left halves of the brain, ensuring their interaction. To connect one hemisphere with the other, commissural fibers form commissures: corpus callosum, commissure of the fornix, anterior commissure. Projection nerve fibers provide connections between the cerebral cortex and the underlying sections: with the basal ganglia, with the nuclei of the brain stem and with the spinal cord. With the help of projection nerve fibers reaching the cerebral cortex, information about the human environment, pictures of the external world are “projected” onto the cortex, as if on a screen. Here, a higher analysis of the information received here is carried out, its assessment with the participation of consciousness. the nucleus with the interaction of the telomos callosum of the cerebral cortex with the basal ganglia of the brain stem in the human environment of the world analysis assessment of consciousness

Blood-brain barrier and its functions Among the homeostatic adaptive mechanisms designed to protect organs and tissues from foreign substances and regulate the constancy of the composition of tissue intercellular fluid, the blood-brain barrier occupies a leading place. According to the definition of L. S. Stern, the blood-brain barrier combines a set of physiological mechanisms and corresponding anatomical formations in the central nervous system involved in regulating the composition of the cerebrospinal fluid (CSF).

In ideas about the blood-brain barrier, the following are emphasized as the main provisions: 1) the penetration of substances into the brain occurs mainly not through the cerebrospinal fluid pathways, but through the circulatory system at the level of the capillary nerve cell; 2) the blood-brain barrier is largely not an anatomical formation, but a functional concept that characterizes a certain physiological mechanism. Like any physiological mechanism existing in the body, the blood-brain barrier is under the regulatory influence of the nervous and humoral systems; 3) among the factors that control the blood-brain barrier, the leading one is the level of activity and metabolism of nervous tissue

The significance of the BBB The blood-brain barrier regulates the penetration of biologically active substances, metabolites, chemicals that affect the sensitive structures of the brain from the blood into the brain, and prevents the entry of foreign substances, microorganisms, and toxins into the brain. The main function characterizing the blood-brain barrier is the permeability of the cell wall. The required level of physiological permeability, adequate to the functional state of the body, determines the dynamics of the entry of physiologically active substances into the nerve cells of the brain.

Structure of histohematic barriers (according to Ya. A. Rosin). SC capillary wall; EC endothelium of the blood capillary; BM basement membrane; AC argyrophilic layer; CPO cells of the organ parenchyma; TSC cell transport system (endoplasmic reticulum); NM nuclear membrane; I am the core; E erythrocyte.

The histohematic barrier has a dual function: regulatory and protective. The regulatory function ensures the relative constancy of physical and physicochemical properties, chemical composition, and physiological activity of the intercellular environment of an organ, depending on its functional state. The protective function of the histohematic barrier is to protect organs from the entry of foreign or toxic substances of endo- and exogenous nature.

The leading component of the morphological substrate of the blood-brain barrier, which ensures its functions, is the wall of the brain capillary. There are two mechanisms for the penetration of the substance into brain cells: through the cerebrospinal fluid, which serves as an intermediate link between the blood and the nerve or glial cell, which performs a nutritional function (the so-called cerebrospinal fluid pathway) through the capillary wall. In an adult organism, the main route of movement of substances into nerve cells is hematogenous (through the walls of capillaries); the liquor pathway becomes auxiliary, additional.

The permeability of the blood-brain barrier depends on the functional state of the body, the content of mediators, hormones, and ions in the blood. An increase in their concentration in the blood leads to a decrease in the permeability of the blood-brain barrier for these substances

Functional system of the blood-brain barrier The functional system of the blood-brain barrier appears to be an important component of neurohumoral regulation. In particular, the principle of chemical feedback in the body is realized through the blood-brain barrier. This is how the mechanism of homeostatic regulation of the composition of the internal environment of the body is carried out. Regulation of the functions of the blood-brain barrier is carried out by the higher parts of the central nervous system and humoral factors. The hypothalamic-pituitary adrenal system plays a significant role in regulation. In the neurohumoral regulation of the blood-brain barrier, metabolic processes, in particular in brain tissue, are important. With various types of cerebral pathology, for example injuries, various inflammatory lesions of brain tissue, there is a need to artificially reduce the level of permeability of the blood-brain barrier. Pharmacological interventions can increase or decrease the penetration into the brain of various substances introduced from the outside or circulating in the blood.

The basis of nervous regulation is a reflex - the body's response to changes in the internal and external environment, carried out with the participation of the central nervous system. Under natural conditions, a reflex reaction occurs with threshold, supra-threshold stimulation of the input of the reflex arc of the receptive field of a given reflex. A receptive field is a certain area of ​​the perceptive sensitive surface of the body with receptor cells located here, the irritation of which initiates and triggers a reflex reaction. The receptive fields of various reflexes have a specific localization, receptor cells have a corresponding specialization for optimal perception of adequate stimuli (for example, photoreceptors are located in the retina; auditory hair receptors in the spiral (corti) organ; proprioceptors in muscles, tendons, joint cavities; taste buds on the surface tongue; olfactory in the mucous membrane of the nasal passages; pain, temperature, tactile receptors in the skin, etc.

The structural basis of a reflex is a reflex arc, a sequentially connected chain of nerve cells that ensures the implementation of a reaction, or response, to stimulation. The reflex arc consists of afferent, central and efferent links interconnected by synaptic connections. The afferent part of the arc begins with receptor formations, the purpose of which is to transform the energy of external stimuli into the energy of a nerve impulse arriving through the afferent link of the reflex arc to the central nervous system

There are various classifications of reflexes: according to the methods of their invocation, the characteristics of the receptors, the central nervous structures that support them, biological significance, the complexity of the neural structure of the reflex arc, etc. According to the method of induction, unconditioned reflexes (a category of reflex reactions transmitted by inheritance) are distinguished: conditioned reflexes ( reflex reactions acquired during the individual life of the organism).

A conditioned reflex is a reflex characteristic of an individual. They arise during the life of an individual and are not fixed genetically (not inherited). They appear under certain conditions and disappear in their absence. They are formed on the basis of unconditioned reflexes with the participation of higher parts of the brain. Conditioned reflex reactions depend on past experience, on the specific conditions in which the conditioned reflex is formed. reflex The study of conditioned reflexes is associated primarily with the name of I. P. Pavlov. He showed that a new conditioned stimulus can trigger a reflex response if it is presented for some time together with an unconditioned stimulus. For example, if you let a dog smell meat, it will secrete gastric juice (this is an unconditioned reflex). If, simultaneously with the appearance of meat, a bell rings, then the dog’s nervous system associates this sound with food, and gastric juice will be released in response to the bell, even if the meat is not presented.I. P. Pavlovastimulsobakemeat gastric juice

Classifications of reflexes. There are exteroceptive reflexes - reflex reactions initiated by irritation of numerous exteroceptors (pain, temperature, tactile, etc.), interoceptive reflexes (reflex reactions triggered by irritation of interoceptors: chemo-, baro-, osmoreceptors, etc.), proprioceptive reflexes ( reflex reactions carried out in response to irritation of proprioceptors of muscles, tendons, articular surfaces, etc.). Depending on the level of activation of parts of the brain, spinal, boulevard, mesencephalic, diencephalic, and cortical reflex reactions are differentiated. According to their biological purpose, reflexes are divided into food, defensive, sexual, etc.

Types of reflexes Local reflexes are carried out through the ganglia of the autonomic nervous system, which are considered as nerve centers located on the periphery. Due to local reflexes, control occurs, for example, the motor and secretory functions of the small and large intestines. Central reflexes occur with the obligatory involvement of various levels of the central nervous system (from the spinal cord to the cerebral cortex). An example of such reflexes is the release of saliva when the receptors in the oral cavity are irritated, the lowering of the eyelid when the sclera of the eye is irritated, the withdrawal of the hand when the skin of the fingers is irritated, etc.

Conditioned reflexes underlie acquired behavior. These are the simplest programs. The world around us is constantly changing, so only those who quickly and expediently respond to these changes can live in it successfully. As we gain life experience, a system of conditioned reflex connections develops in the cerebral cortex. Such a system is called a dynamic stereotype. It underlies many habits and skills. For example, having learned to skate or bicycle, we subsequently no longer think about how we should move so as not to fall.

Feedback principle The idea of ​​a reflex reaction as an expedient response of the body dictates the need to supplement the reflex arc with another link, a feedback loop designed to establish a connection between the realized result of the reflex reaction and the nerve center that issues executive commands. Feedback transforms an open reflex arc into a closed one. It can be implemented in different ways: from the executive structure to the nerve center (intermediate or efferent motor neuron), for example, through the recurrent axon collateral of a pyramidal neuron of the cerebral cortex or a motor cell of the anterior horn of the spinal cord. Feedback can also be provided by nerve fibers entering the receptor structures and controlling the sensitivity of the receptor afferent structures of the analyzer. This structure of the reflex arc turns it into a self-adjusting neural circuit for regulating physiological function, improving the reflex response and, in general, optimizing the behavior of the body.

1. For the interconnection of sets of neurons (nerve centers) of one or different levels of the nervous system; 2. To transmit afferent information to the regulators of the nervous system (to the nerve centers); 3. To generate control signals. The name “conducting pathways” does not mean that these pathways serve exclusively to conduct afferent or efferent information, similar to the conduction of electric current in the simplest electrical circuits. Chains of neurons - pathways are essentially hierarchically interacting elements of the system regulator. It is in these hierarchical chains, as elements of regulators, and not just at the end points of paths (for example, in the cerebral cortex), that information is processed and control signals are generated for control objects of body systems. 4. To transmit control signals from nervous system regulators to control objects - organs and organ systems. Thus, the initially purely anatomical concept of “path”, or the collective “path”, “tract” also has a physiological meaning and is closely related to such physiological concepts as a control system, inputs, regulator, outputs.

summary of other presentations

“Fundamentals of higher nervous activity” - Internal inhibition. Reflexes. Paradoxical dream. External braking. Insight. Neural connection. Sequence of elements of the reflex arc. Choleric temperament. Formation of a conditioned reflex. Dream. Acquired by the body during life. Congenital reflexes. Creation of the doctrine of GNI. Wakefulness. Human children. Sanguine temperament. Type of internal braking. Correct judgments.

“Autonomic division of the nervous system” - Pilomotor reflex. Raynaud's disease. Pharmacological tests. Parasympathetic part of the autonomic nervous system. Functions of internal organs. Test with pilocarpine. Solar reflex. Limbic system. Bulbar department. The sympathetic part of the autonomic nervous system. Bernard's syndrome. Features of autonomic innervation. Damage to the autonomic ganglia of the face. Sacral department. Cold test. Sympathotonic crises.

“Evolution of the nervous system” - Class Mammals. Diencephalon. Nervous system of vertebrates. Shellfish. Pisces class. Medulla oblongata (hind) brain. Anterior section. Evolution of the nervous system. Cerebellum. Bird class. Reflex. Class Amphibians. Neuron. The nervous system is a collection of various structures of nervous tissue. Evolution of the nervous system of vertebrates. Divisions of the brain. Cells of the body. Nerve tissue is a collection of nerve cells.

“The work of the human nervous system” - Ivan Petrovich Pavlov. Sechenov Ivan Mikhailovich. Reflex arc. Reflex principle of the nervous system. Active state of neurons. Comparison of unconditioned and conditioned reflexes. The concept of reflex. M. Gorky. Find a match. Knee reflex.

“Physiology of VND” - Physiology of higher nervous activity. Decreased metabolic activity. Cochlear implant. Connecting neurons. Patient. Global workspace. Vegetative state. Psychophysiological problem. Flexibility of modules. Modern neurophysiological theories of consciousness. Creating a global workspace. A variety of different states of consciousness. The problem of consciousness in cognitive science.

“Features of human higher nervous activity” - Unconditional inhibition. Classification of conditioned reflexes. Development of a conditioned reflex. Features of human higher nervous activity. Formation of a temporary connection. Types of inhibition of mental activity. The dog eats from a bowl. Unconditioned reflexes. Insight. Reflexes. Conditioned reflexes. Saliva is released. Brain functions. Fistula for collecting saliva. Types of instincts. Basic characteristics of a conditioned reflex.

TOPIC: CENTRAL NERVOUS SYSTEM (CNS) PLAN: 1. The role of the CNS in the integrative, adaptive activity of the body. 2. Neuron - as a structural and functional unit of the central nervous system. 3. Synapses, structure, functions. 4. Reflex principle of regulation of functions. 5. History of the development of reflex theory. 6.Methods for studying the central nervous system.

The central nervous system carries out: 1. Individual adaptation of the body to the external environment. 2. Integrative and coordinating functions. 3. Forms goal-oriented behavior. 4. Performs analysis and synthesis of received stimuli. 5. Forms a flow of efferent impulses. 6. Maintains the tone of body systems. The modern concept of the central nervous system is based on the neural theory.

The central nervous system is a collection of nerve cells or neurons. Neuron. Sizes from 3 to 130 microns. All neurons, regardless of size, consist of: 1. Body (soma). 2. Axon dendritic processes Structural and functional elements of the central nervous system. The cluster of neuron bodies makes up the gray matter of the central nervous system, and the cluster of processes makes up the white matter.

Each cell element performs a specific function: The neuron body contains various intracellular organelles and ensures the life of the cell. The body membrane is covered with synapses, therefore it perceives and integrates impulses coming from other neurons. Axon (long process) - conducts a nerve impulse from the body of a nerve cell and to the periphery or to other neurons. Dendrites (short, branching) - perceive irritations and communicate between nerve cells.

1. Depending on the number of processes, they are distinguished: - unipolar - one process (in the nuclei of the trigeminal nerve) - bipolar - one axon and one dendrite - multipolar - several dendrites and one axon 2. In functional terms: - afferent or receptor - (perceive signals from receptors and carried to the central nervous system) - intercalary - provide communication between afferent and efferent neurons. - efferent - conduct impulses from the central nervous system to the periphery. They are of 2 types: motor neurons and efferent neurons of the ANS - excitatory - inhibitory CLASSIFICATION OF NEURONS

The relationship between neurons is carried out through synapses. 1. Presynaptic membrane 2. Synaptic cleft 3. Postsynaptic membrane with receptors. Receptors: cholinergic receptors (M and N cholinergic receptors), adrenergic receptors - α and β Axonal hillock (axon extension)

CLASSIFICATION OF SYNAPSES: 1. By location: - axoaxonal - axodendritic - neuromuscular - dendrodendritic - axosomatic 2. By the nature of the action: excitatory and inhibitory. 3. By signal transmission method: - electrical - chemical - mixed

The transmission of excitation in chemical synapses occurs due to mediators, which are of 2 types - excitatory and inhibitory. Exciting agents - acetylcholine, adrenaline, serotonin, dopamine. Inhibitory – gamma-aminobutyric acid (GABA), glycine, histamine, β-alanine, etc. Mechanism of excitation transmission in chemical synapses

The mechanism of excitation transmission in the excitatory synapse (chemical synapse): impulse, nerve ending into synaptic plaques, depolarization of the presynaptic membrane (input of Ca++ and output of transmitters), neurotransmitters, synaptic cleft, postsynaptic membrane (interaction with receptors), generation of EPSP AP.

1. In chemical synapses, excitation is transmitted using mediators. 2. Chemical synapses have one-way conduction of excitation. 3.Fatigue (depletion of neurotransmitter reserves). 4.Low lability imp/sec. 5. Summation of excitation 6. Blazing a path 7. Synaptic delay (0.2-0.5 m/s). 8. Selective sensitivity to pharmacological and biological substances. 9.Chemical synapses are sensitive to temperature changes. 10. There is trace depolarization at chemical synapses. PHYSIOLOGICAL PROPERTIES OF CHEMICAL SYNAPSES

REFLECTOR PRINCIPLE OF REGULATION OF FUNCTION The activity of the body is a natural reflex reaction to a stimulus. In the development of reflex theory, the following periods are distinguished: 1. Descartes (16th century) 2. Sechenovsky 3. Pavlovsky 4. Modern, neurocybernetic.

METHODS OF RESEARCH OF THE CNS 1. Extirpation (removal: partial, complete) 2. Irritation (electrical, chemical) 3. Radioisotope 4. Modeling (physical, mathematical, conceptual) 5. EEG (registration of electrical potentials) 6. Stereotactic technique. 7. Development of conditioned reflexes 8. Computed tomography 9. Pathological method