general characteristics
The evolutionary processes to which multicellular organisms have been subjected for centuries have led to the need for regulation and coordination of all life functions. These mechanisms contributed to the adaptation of individuals to changing environmental parameters. The result was that the departments of the central nervous system became complex in structure and functioning.
In essence, the central nervous system is a highly organized set of special structural units that combine and coordinate the activity of each tissue, system and organ, both from the inside and when interacting with the environment from the outside. It is represented by two important organs - the intracranial and intravertebral brain. Whereas cranial nerve fibers are not related to the central nervous system. This is already a peripheral innervation system.
Basically, functional units related to the brain and spinal cord are responsible for the perception of information from external/internal stimuli, its processing and the formation of an adequate response. Thanks to this system, which is part of the whole organism, the full interaction of people with the world around them is ensured - through memory, thinking, emotions, and creative processes.
- 1. Basic principles of the functioning of the central nervous system. Structure, functions, methods of studying the central nervous system
- 2. Neuron. Structural features, meaning, types
- 3. Reflex arc, its components, types, functions
- 4. Functional systems of the body
- 5. Coordination activities of the central nervous system
- 6. Types of inhibition, interaction of excitation and inhibition processes in the central nervous system. Experience of I. M. Sechenov
- 7. Methods for studying the central nervous system
LECTURE No. 6. Physiology of the central nervous system
1. Basic principles of the functioning of the central nervous system. Structure, functions, methods of studying the central nervous system
The basic principle of the functioning of the central nervous system is the process of regulation, control of physiological functions, which are aimed at maintaining the constancy of the properties and composition of the internal environment of the body. The central nervous system ensures optimal relationships between the body and the environment, stability, integrity, and the optimal level of vital activity of the body.
There are two main types of regulation: humoral and nervous.
The humoral control process involves changing the physiological activity of the body under the influence of chemicals that are delivered by body fluids. The source of information transfer is chemicals - utilizons, metabolic products (carbon dioxide, glucose, fatty acids), informons, hormones of the endocrine glands, local or tissue hormones.
The nervous process of regulation involves controlling changes in physiological functions along nerve fibers using excitation potential under the influence of information transfer.
Characteristics:
1) is a later product of evolution;
2) provides quick regulation;
3) has an exact target of impact;
4) implements an economical method of regulation;
5) ensures high reliability of information transmission.
In the body, the nervous and humoral mechanisms work as a single system of neurohumoral control. This is a combined form, where two control mechanisms are used simultaneously; they are interconnected and interdependent.
The nervous system is a collection of nerve cells, or neurons.
According to localization they distinguish:
1) central section – brain and spinal cord;
2) peripheral - processes of nerve cells of the brain and spinal cord.
According to functional features they are distinguished:
1) somatic department, regulating motor activity;
2) vegetative, regulating the activity of internal organs, endocrine glands, blood vessels, trophic innervation of muscles and the central nervous system itself.
Functions of the nervous system:
1) integrative-coordination function. Provides the functions of various organs and physiological systems, coordinates their activities with each other;
2) ensuring close connections between the human body and the environment at the biological and social levels;
3) regulation of the level of metabolic processes in various organs and tissues, as well as in oneself;
4) ensuring mental activity by the higher departments of the central nervous system.
2. Neuron. Structural features, meaning, types
The structural and functional unit of nervous tissue is a nerve cell - neuron
.
A neuron is a specialized cell that is capable of receiving, encoding, transmitting and storing information, establishing contacts with other neurons, and organizing the body’s response to irritation.
Functionally, a neuron is divided into:
1) the receptive part (dendrites and membrane of the soma of the neuron);
2) integrative part (soma with axon hillock);
3) transmitting part (axon hillock with axon).
Perceiving part.
Dendrites
– the main receptive field of the neuron. The dendrite membrane is capable of responding to mediators. A neuron has several branching dendrites. This is explained by the fact that a neuron as an information formation must have a large number of inputs. Through specialized contacts, information flows from one neuron to another. These contacts are called "spines".
The neuron soma membrane is 6 nm thick and consists of two layers of lipid molecules. The hydrophilic ends of these molecules face the water phase: one layer of molecules faces inward, the other outward. The hydrophilic ends are turned towards each other - inside the membrane. The lipid bilayer of the membrane contains proteins that perform several functions:
1) pump proteins - move ions and molecules in the cell against a concentration gradient;
2) proteins embedded in the channels provide selective membrane permeability;
3) receptor proteins recognize the necessary molecules and fix them on the membrane;
4) enzymes facilitate the occurrence of a chemical reaction on the surface of the neuron.
In some cases, the same protein can serve as both a receptor, an enzyme, and a pump.
Integrative part.
Axon hillock
– the point where the axon exits the neuron.
The neuron soma (neuron body) performs, along with an informational and trophic function, relative to its processes and synapses. The soma ensures the growth of dendrites and axons. The neuron soma is enclosed in a multilayer membrane, which ensures the formation and propagation of electrotonic potential to the axon hillock.
Transmitting part.
Axon
- an outgrowth of the cytoplasm, adapted to carry information that is collected by dendrites and processed in the neuron. The axon of a dendritic cell has a constant diameter and is covered with a myelin sheath, which is formed from glia; the axon has branched endings containing mitochondria and secretory formations.
Functions of neurons:
1) generalization of the nerve impulse;
2) receiving, storing and transmitting information;
3) the ability to summarize excitatory and inhibitory signals (integrative function).
Types of neurons:
1) by localization:
a) central (brain and spinal cord);
b) peripheral (cerebral ganglia, cranial nerves);
2) depending on the function:
a) afferent (sensitive), carrying information from receptors to the central nervous system;
b) intercalary (connector), in the elementary case providing communication between afferent and efferent neurons;
c) efferent:
– motor – anterior horns of the spinal cord;
– secretory – lateral horns of the spinal cord;
3) depending on the functions:
a) stimulating;
b) inhibitory;
4) depending on the biochemical characteristics, on the nature of the mediator;
5) depending on the quality of the stimulus that is perceived by the neuron:
a) monomodal;
b) multimodal.
3. Reflex arc, its components, types, functions
The activity of the body is a natural reflex reaction to a stimulus. Reflex
– the body’s reaction to irritation of receptors, which is carried out with the participation of the central nervous system. The structural basis of the reflex is the reflex arc.
Reflex arc
- a series-connected chain of nerve cells that ensures the implementation of a reaction, a response to irritation.
The reflex arc consists of six components: receptors, afferent (sensitive) path, reflex center, efferent (motor, secretory) path, effector (working organ), feedback.
Reflex arcs can be of two types:
1) simple - monosynaptic reflex arcs (reflex arc of the tendon reflex), consisting of 2 neurons (receptor (afferent) and effector), there is 1 synapse between them;
2) complex – polysynaptic reflex arcs. They consist of 3 neurons (there may be more) - a receptor, one or more intercalary and an effector.
The idea of the reflex arc as an expedient response of the body dictates the need to supplement the reflex arc with another link - a feedback loop. This component establishes a connection between the realized result of the reflex reaction and the nerve center that issues executive commands. With the help of this component, the open reflex arc is transformed into a closed one.
Features of a simple monosynaptic reflex arc:
1) geographically close receptor and effector;
2) reflex arc two-neuron, monosynaptic;
3) nerve fibers of group A? (70-120 m/s);
4) short reflex time;
5) muscles contracting according to the type of single muscle contraction.
Features of a complex monosynaptic reflex arc:
1) territorially separated receptor and effector;
2) three-neuron receptor arch (there may be more neurons);
3) the presence of nerve fibers of groups C and B;
4) muscle contraction according to the tetanus type.
Features of the autonomic reflex:
1) the interneuron is located in the lateral horns;
2) the preganglionic nerve pathway begins from the lateral horns, after the ganglion - the postganglionic;
3) the efferent path of the autonomic nervous arch reflex is interrupted by the autonomic ganglion, in which the efferent neuron lies.
The difference between the sympathetic nervous arch and the parasympathetic: the sympathetic nervous arch has a short preganglionic pathway, since the autonomic ganglion lies closer to the spinal cord, and the postganglionic pathway is long.
In the parasympathetic arc, the opposite is true: the preganglionic pathway is long, since the ganglion lies close to the organ or in the organ itself, and the postganglionic pathway is short.
4. Functional systems of the body
Functional system
– temporary functional unification of the nerve centers of various organs and systems of the body to achieve a final beneficial result.
The beneficial result is a self-forming factor of the nervous system. The result of an action is a vital adaptive indicator that is necessary for the normal functioning of the body.
There are several groups of final useful results:
1) metabolic – a consequence of metabolic processes at the molecular level that create substances and end products necessary for life;
2) homeostatic – constancy of indicators of the state and composition of the body’s media;
3) behavioral – the result of biological needs (sexual, food, drinking);
4) social – satisfaction of social and spiritual needs.
The functional system includes various organs and systems, each of which takes an active part in achieving a useful result.
The functional system, according to P.K. Anokhin, includes five main components:
1) a useful adaptive result - that for which a functional system is created;
2) control apparatus (result acceptor) – a group of nerve cells in which a model of the future result is formed;
3) reverse afferentation (supplies information from the receptor to the central link of the functional system) - secondary afferent nerve impulses that go to the acceptor of the result of the action to evaluate the final result;
4) control apparatus (central link) – functional association of nerve centers with the endocrine system;
5) executive components (reaction apparatus) - these are the organs and physiological systems of the body (vegetative, endocrine, somatic). Consists of four components:
a) internal organs;
b) endocrine glands;
c) skeletal muscles;
d) behavioral reactions.
Properties of a functional system:
1) dynamism. The functional system may include additional organs and systems, which depends on the complexity of the current situation;
2) the ability to self-regulate. When the controlled value or the final useful result deviates from the optimal value, a series of reactions of a spontaneous complex occur, which returns the indicators to the optimal level. Self-regulation occurs in the presence of feedback.
Several functional systems operate simultaneously in the body. They are in continuous interaction, which is subject to certain principles:
1) the principle of the system of genesis. Selective maturation and evolution of functional systems occur (functional circulatory, respiratory, nutritional systems mature and develop earlier than others);
2) the principle of multiply connected interaction. There is a generalization of the activities of various functional systems aimed at achieving a multicomponent result (homeostasis parameters);
3) the principle of hierarchy. Functional systems are arranged in a certain row in accordance with their significance (functional system of tissue integrity, functional nutrition system, functional reproduction system, etc.);
4) the principle of sequential dynamic interaction. There is a clear sequence of changing the activities of one functional system to another.
5. Coordination activities of the central nervous system
Coordination activity (CA) of the CNS is the coordinated work of CNS neurons, based on the interaction of neurons with each other.
CD functions:
1) ensures clear performance of certain functions and reflexes;
2) ensures the consistent inclusion of various nerve centers in the work to ensure complex forms of activity;
3) ensures the coordinated work of various nerve centers (during the act of swallowing, the breath is held at the moment of swallowing; when the swallowing center is excited, the breathing center is inhibited).
Basic principles of CNS CD and their neural mechanisms.
1. The principle of irradiation (propagation). When small groups of neurons are excited, the excitation spreads to a significant number of neurons. Irradiation is explained:
1) the presence of branched endings of axons and dendrites, due to branching, impulses spread to a large number of neurons;
2) the presence of interneurons in the central nervous system, which ensure the transmission of impulses from cell to cell. Irradiation has boundaries, which are provided by the inhibitory neuron.
2. The principle of convergence. When a large number of neurons are excited, the excitation can converge to one group of nerve cells.
3. The principle of reciprocity - coordinated work of nerve centers, especially in opposite reflexes (flexion, extension, etc.).
4. The principle of dominance. Dominant
– the dominant focus of excitation in the central nervous system at the moment. This is the center of persistent, unwavering, non-spreading excitation. It has certain properties: it suppresses the activity of other nerve centers, has increased excitability, attracts nerve impulses from other foci, sums up nerve impulses. Foci of dominance are of two types: exogenous (caused by environmental factors) and endogenous (caused by internal environmental factors). The dominant underlies the formation of a conditioned reflex.
5. Feedback principle. Feedback is a flow of impulses into the nervous system that informs the central nervous system about how the response is carried out, whether it is sufficient or not. There are two types of feedback:
1) positive feedback, causing an increase in the response from the nervous system. Underlies the vicious circle that leads to the development of diseases;
2) negative feedback, reducing the activity of CNS neurons and response. Underlies self-regulation.
6. The principle of subordination. In the central nervous system there is a certain subordination of departments to each other, the highest department being the cerebral cortex.
7. The principle of interaction between the processes of excitation and inhibition. The central nervous system coordinates the processes of excitation and inhibition:
both processes are capable of convergence; the process of excitation and, to a lesser extent, inhibition are capable of irradiation. Inhibition and excitation are connected by inductive relationships. The process of excitation induces inhibition, and vice versa. There are two types of induction:
1) consistent. The process of excitation and inhibition alternates in time;
2) mutual. There are two processes at the same time - excitation and inhibition. Mutual induction is carried out through positive and negative mutual induction: if inhibition occurs in a group of neurons, then foci of excitation arise around it (positive mutual induction), and vice versa.
According to I.P. Pavlov’s definition, excitation and inhibition are two sides of the same process. The coordination activity of the central nervous system ensures clear interaction between individual nerve cells and individual groups of nerve cells. There are three levels of integration.
The first level is ensured due to the fact that impulses from different neurons can converge on the body of one neuron, resulting in either summation or a decrease in excitation.
The second level provides interactions between individual groups of cells.
The third level is provided by cells of the cerebral cortex, which contribute to a more advanced level of adaptation of the activity of the central nervous system to the needs of the body.
6. Types of inhibition, interaction of excitation and inhibition processes in the central nervous system. Experience of I. M. Sechenov
Braking
– an active process that occurs when stimuli act on tissue, manifests itself in the suppression of other excitation, there is no functional function of the tissue.
Inhibition can develop only in the form of a local response.
There are two types of braking:
1) primary. For its occurrence, the presence of special inhibitory neurons is necessary. Inhibition occurs primarily without prior excitation under the influence of an inhibitory transmitter. There are two types of primary inhibition:
a) presynaptic in the axo-axonal synapse;
b) postsynaptic in the axodendritic synapse.
2) secondary. It does not require special inhibitory structures, occurs as a result of changes in the functional activity of ordinary excitable structures, and is always associated with the process of excitation. Types of secondary braking:
a) transcendental, which occurs when there is a large flow of information entering the cell. The flow of information lies beyond the functionality of the neuron;
b) pessimal, which occurs with a high frequency of irritation;
c) parabiotic, which occurs during strong and long-term irritation;
d) inhibition following excitation, resulting from a decrease in the functional state of neurons after excitation;
e) inhibition according to the principle of negative induction;
e) inhibition of conditioned reflexes.
The processes of excitation and inhibition are closely related to each other, occur simultaneously and are different manifestations of a single process. Foci of excitation and inhibition are mobile, cover larger or smaller areas of neuronal populations and can be more or less pronounced. Excitation is certainly replaced by inhibition, and vice versa, that is, there is an inductive relationship between inhibition and excitation.
Inhibition underlies the coordination of movements and protects central neurons from overexcitation. Inhibition in the central nervous system can occur when nerve impulses of varying strength from several stimuli simultaneously enter the spinal cord. Stronger stimulation inhibits reflexes that should have occurred in response to weaker ones.
In 1862, I.M. Sechenov discovered the phenomenon of central inhibition. He proved in his experiment that irritation with a sodium chloride crystal of the visual thalamus of a frog (the cerebral hemispheres have been removed) causes inhibition of spinal cord reflexes. After the stimulus was removed, the reflex activity of the spinal cord was restored. The result of this experiment allowed I.M. Secheny to conclude that in the central nervous system, along with the process of excitation, a process of inhibition develops, which is capable of inhibiting the reflex acts of the body. N. E. Vvedensky suggested that the phenomenon of inhibition is based on the principle of negative induction: a more excitable area in the central nervous system inhibits the activity of less excitable areas.
Modern interpretation of the experiment of I.M. Sechenov (I.M. Sechenov irritated the reticular formation of the brainstem): excitation of the reticular formation increases the activity of inhibitory neurons of the spinal cord - Renshaw cells, which leads to inhibition of ?-motoneurons of the spinal cord and inhibits the reflex activity of the spinal cord.
7. Methods for studying the central nervous system
There are two large groups of methods for studying the central nervous system:
1) experimental method, which is carried out on animals;
2) a clinical method that is applicable to humans.
Among the experimental methods
classical physiology includes methods aimed at activating or suppressing the nerve formation being studied. These include:
1) method of transverse section of the central nervous system at various levels;
2) method of extirpation (removal of various parts, denervation of the organ);
3) method of irritation by activation (adequate irritation - irritation with an electrical impulse similar to a nervous one; inadequate irritation - irritation with chemical compounds, graded irritation with electric current) or suppression (blocking the transmission of excitation under the influence of cold, chemical agents, direct current);
4) observation (one of the oldest methods of studying the functioning of the central nervous system that has not lost its significance. It can be used independently, and is often used in combination with other methods).
Experimental methods are often combined with each other when conducting experiments.
Clinical method
aimed at studying the physiological state of the central nervous system in humans. It includes the following methods:
1) observation;
2) method of recording and analyzing electrical potentials of the brain (electro-, pneumo-, magnetoencephalography);
3) radioisotope method (investigates neurohumoral regulatory systems);
4) conditioned reflex method (studies the functions of the cerebral cortex in the mechanism of learning and the development of adaptive behavior);
5) questionnaire method (assesses the integrative functions of the cerebral cortex);
6) modeling method (mathematical modeling, physical modeling, etc.). A model is an artificially created mechanism that has a certain functional similarity with the mechanism of the human body being studied;
7) cybernetic method (studies control and communication processes in the nervous system). Aimed at studying organization (systemic properties of the nervous system at various levels), management (selection and implementation of influences necessary to ensure the functioning of an organ or system), information activity (the ability to perceive and process information - an impulse in order to adapt the body to environmental changes).
Table of contents
Structural features
In humans, from the moment of fertilization of the egg, the development and formation of the central nervous system begins - the brain and also the spinal cord are formed from the neural tube itself. They are protected by bone frames - the skull and vertebrae. Below there are three membranes - hard with arachnoid and vascular. Within their limits there are liquid media - cerebrospinal fluid with blood.
Traditionally, the structure of the central nervous system implies that cells - neurons - are united into special clusters - nerve centers. The bodies of neurons form the gray matter, while their short and long processes form the white substance, conducting signal impulses.
In addition, the central nervous system contains neuroglia, which consists of glial cells. Their number is several times greater than the number of neurons. Therefore, they make up most of the mass of the central nervous system.
In the head section, it is customary to distinguish several segments - the cerebellum with the cerebral hemispheres, as well as the oblongata, middle, intermediate and posterior sections. Each of them bears its own responsibility for the proper functioning of the organ separately, and of the entire organism and systems as a whole. In the spinal cord, gradation is carried out according to the segments of the spinal trunk - from the cervical, to the thoracic and lumbosacral.
Main functions
The main sections of the central nervous system are formed by brain structures consisting of a large number of interconnected and continuously interacting nerve cells. The peripheral section, formed by nerve fibers that innervate skeletal muscles (muscles of the limbs and trunk), receives impulses coming from the central parts of the brain. Thanks to this structure, the functions of the human central nervous system are diverse and ensure the interaction of all parts of the human body.
The structure of the central nervous system maintains the integrity and unity of the body’s vital functions, and the main function of the central system is reduced to the formation of nervous reactions (reflexes) to external stimuli. Interaction with the outside world is predominantly coordinated by the cortical and subcortical zones of the cerebral hemispheres. Functions of the central nervous system include:
- Sensitivity to environmental factors (temperature, humidity, tactile contacts, hearing, vision).
- Motor activity. The spinal and cerebral structures are involved in the organization of voluntary movements.
- Regulation of mental activity and behavior.
- Ensuring the functioning of the pelvic organs (processes of urination and defecation).
- Management of the respiratory and cardiovascular systems.
The central system includes such elements of nervous tissue as afferent and efferent neurons. The former perceive impulses coming from the periphery, the latter transmit them to effector (whose activity is determined by reflexes), executive organs. Effectors are compounds that cause physiological responses by binding to proteins and subsequent regulation of their biological activity.
Anatomy of the brain
The brain, of course, occupies a dominant place in the central nervous system. Inside the cranium, it is represented by two large hemispheres, dotted with deep and shallow grooves, under which other structural units are located:
- The oblong section is localized on the Blumenbach slope. Downwards it smoothly transforms into the spinal cord. On its front surface there is a longitudinal gap, on the sides of which experts identify 2 peculiar elevations in the form of rollers. They are called pyramids with olives. Whereas a similar groove on the posterior surface of the structure with two posterior cords is usually called pillars.
- Above the medulla oblongata is the hindbrain - in the form of the Varoliev bridge, as well as the cerebellum. Outwardly they are similar to the cerebral hemispheres, but functionally they have their own characteristics. Deep in the tissue there are clusters of nuclei from which the cranial nerves originate.
- The relationship between the medulla oblongata and the higher-lying sections is carried out by the midbrain - represented by the legs, nerve bundles, and also the quadrigeminal. It is impossible to overestimate their importance - it is in this zone that many of the most important nerve pathways lie and the nuclei of several pairs of nerves are located.
- Intermediate area - known as the visual thalamus with the subthalamic region, located further from the center of the brain. They contain the primary cells of the visual system, as well as sensitive conductive fibers. The hypothalamus, also known as the subtubercular region, takes part in metabolic processes.
Each of the listed units of the system - from the hemispheres and cerebellum to the brain stem - has its own significance for human life. If a failure occurs in one area - the lining of the central nervous system, for example, a brain tumor, then the effect will be on all parts of the organ.
Anatomical features of the spinal cord
The strong frame of the spinal column reliably protects another structural unit of the central nervous system - the spinal cord. Its length is impressive - from the occipital foramen of the skull to the lumbar vertebrae.
Visually, on both sides one can note the presence of longitudinal grooves, while directly in the center is the spinal canal. On the outside there is a white substance - many processes of nerve cells that are united into fibers. The gray matter is represented mainly by the lateral, as well as the posterior and anterior horny zones - reminiscent of a butterfly in flight.
Motor nerve cells are localized in the anterior horns, and the posterior formations have intercalary neurons that communicate with sensory cells. They are located in the nodal segments of the nervous system.
At the junction of the anterior fibers with the posterior zones, the roots of the spinal cord are formed. They are essentially conductors between the central and peripheral systems. It is due to this anatomical structure that the relationship between different parts of the human body is established and the balance of the internal environment is maintained - by spinal reflexes.
Somatic nervous system
Somatics is a department of the nervous system that is responsible for the delivery of motor and sensory impulses from receptors to the organs of the central nervous system and back. Most of the nerve fibers of the somatic system are concentrated in the skin, muscle frame and organs responsible for sensory perception. It is the somatic nervous system that coordinates almost 100% of the conscious part of the activity of the human body and the processing of information received from the receptors of the sensory organs.
The main elements of somatics are 2 types of neurons:
- sensory or afferent. Regulate the delivery of information to the cells of the central nervous system;
- motor or efferent. They work in the opposite direction, transporting nerve impulses from the central nervous system to cells and tissues.
Both neurons stretch from parts of the central nervous system directly to the final target of impulses, that is, to muscle and receptor cells, and the body in most cases is located directly in the central part of the nervous system, and the processes reach the necessary localization.
In addition to conscious activity, somatics also includes some reflexes controlled unconsciously. With the help of such reactions, the muscular system comes into an active state without waiting for an impulse from the brain, which allows it to act instinctively. This process is possible if the nerve fiber paths pass directly through the spinal cord. An example of such actions is the jerking of the hand when feeling a high temperature or the knee-jerk reflex when hitting a tendon with a hammer.
Autonomic nervous system
The autonomic nervous system, or autonomic nervous system, is a department that coordinates the activity of primarily internal organs. Since the basic processes of life - breathing, metabolism, heartbeat, blood flow, etc. - are not subject to consciousness, autonomic nerve fibers react primarily to changes occurring in the internal environment of the body, remaining indifferent to conscious impulses. Thanks to this, optimal conditions are maintained in the body to provide the energy resources necessary in a particular situation.
The peculiarities of autonomic nervous activity imply that the main fibers are concentrated not only in the organs of the central nervous system, but also in other tissues of the human body. Numerous nodes are scattered throughout the body, forming an autonomous nervous system outside the central nervous system, between the brain centers and organs. Such a network can regulate the simplest functions, but more complex mechanisms still remain under the direct control of the central nervous system.
The key role of vegetatives is to maintain relatively constant homeostasis by self-adjusting the activity of internal organs depending on the needs of the body. Thus, vegetative fibers optimize the secretion of hormones, the speed and intensity of blood supply to tissues, the intensity and frequency of respiration and heart rate and other key mechanisms that must respond to changes in the external environment (for example, with intense physical activity, increased temperature or humidity, atmospheric pressure and etc.). Thanks to these processes, compensatory and adaptive reactions are ensured that keep the body in optimal shape under any circumstances. Since the unconscious activity of internal organs can be regulated in two directions (activation and suppression), autonomics can also be divided into 2 sections - parasympathetic and sympathetic.
Sympathetic nervous system
The sympathetic division of the autonomic system is directly connected to the spinal substance, located from the first thoracic to the third lumbar vertebra. It is here that the activity of internal organs is stimulated, which is necessary during times of increased energy consumption - during physical exertion, during stress, intense work or emotional shock. Such mechanisms make it possible to support the body by providing it with the resources necessary to overcome unfavorable conditions.
Under the influence of sympathy, breathing and pulsation of blood vessels become more frequent, due to which the tissues are better supplied with oxygen and energy is released from the cells more quickly. Thanks to this, a person can work more actively, coping with increased loads in unfavorable conditions. However, these resources cannot be infinite: sooner or later the amount of energy reserves decreases, and the body can no longer function “at high speed” without a break. Then the parasympathetic department of the vegetative system comes into play.
Functions of the central nervous system
Based on the structural features and location of the structures of the central nervous system, its main functions follow:
- integrative - establishing relationships between cells in tissues, organs in systems to form a single, highly organized human body;
- coordinating - ensuring the coordination of the actions of various bodies to achieve a single task facing a person, for example, adaptation to a dramatically changed situation;
- regulatory - the structures of the nervous system control all processes occurring within, no activity occurs without their participation;
- trophic – regulates trophism, as well as the intensity of metabolic processes in tissues, so that the response to changes is adequate and rapid;
- adaptive - analysis and subsequent synthesis of information coming from outside to adapt to the external environment.
In addition to all the listed functions, the importance of the central nervous system lies in the formation of non-directional behavior - in accordance with a person’s dominant needs. As the underlying ones are satisfied - nutrition, breathing, people begin to look for their inner “I”, spiritual values.
Despite the abundance of scientific work on the central nervous system, there are many unknowns in this area. Humanity awaits many more discoveries.
Diagnosis and treatment
Doppler ultrasound, magnetic resonance imaging and computed tomography may be required to make a diagnosis. Based on the results of the examination, the doctor prescribes appropriate treatment.
In addition, ultrasound and transcranial Doppler ultrasound are used to identify pathology. Duplex scanning may also be required, which is the safest and most informative.
Depending on the diagnosis, medications with different properties can be used, namely:
- anticonvulsants;
- improving blood circulation in the brain;
- sedatives;
- improving vascular permeability;
- neuroleptics.
Congenital pathologies will not be so easy to cure. The first priority is to eliminate the negative symptoms of the existing disease.
The central nervous system is a complex organization with many components that are closely interconnected. With pathology of one of them, the entire body suffers, which leads to impairments in the ability to move, hear, speak and other necessary functions.
