Second higher education "psychology" in the MBA format
item:Anatomy and evolution of the human nervous system.
Manual "Anatomy of the Central Nervous System"
1.1. History of the anatomy of the central nervous system
1.2. Research methods in anatomy
1.3. Anatomical terminology
Human anatomy is a science that studies the structure of the human body and the patterns of development of this structure.
Modern anatomy, being a part of morphology, not only examines the structure, but also tries to explain the principles and patterns of the formation of certain structures. The anatomy of the central nervous system (CNS) is part of the human anatomy. Knowledge of the anatomy of the central nervous system is necessary to understand the relationship of psychological processes with certain morphological structures, both in norm and in pathology.
1.1. History of the anatomy of the central nervous system
Already in primitive times, there was knowledge about the location of the vital organs of humans and animals, as evidenced by the rock paintings. V Ancient world
, especially in Egypt, in connection with the mummification of corpses, some organs have been described, but their functions were not always presented correctly.
Scientists greatly influenced the development of medicine and anatomy. Ancient Greece ... An outstanding representative of Greek medicine and anatomy was Hippocrates (c. 460-377 BC). He considered four "juices" to be the basis of the structure of the body: blood (sanguis), mucus (phlegma), bile (сhole) and black bile (telaina сhole). From the predominance of one of these juices, in his opinion, the types of a person's temperament depend: sanguine, phlegmatic, choleric and melancholic. This is how the "humoral" (fluid) theory of the structure of the body arose. A similar classification, but, of course, with a different semantic content, has survived to this day.
V Ancient rome the most prominent representatives of medicine were Celsus and Galen. Aulus Cornelius Celus (1st century BC) is the author of an eight-volume treatise "On Medicine", in which he brought together the knowledge he knew of anatomy and practical medicine of ancient times. A great contribution to the development of anatomy was made by the Roman physician Galen (c. 130-200 AD), who was the first to introduce the method of animal vivisection into science and wrote the classic treatise "On the Parts of the Human Body", in which he was the first to give an anatomical and physiological description of the integral organism. Galen considered the human body to be composed of solid and fluid parts, and based his scientific conclusions on observations of sick people and on the results of autopsies on animal corpses. He was also the founder of experimental medicine, conducting various experiments on animals. However, the anatomical concepts of this scientist were not without flaws. For example, Galen spent most of his scientific research on pigs, whose organism, although close to that of a human, still has a number of significant differences from it. In particular, Galen giving great importance he discovered a "miraculous network" (rete mirabile) - the circulatory plexus at the base of the brain, since he believed that it was there that the "animal spirit" was formed, which controls movements and sensations. This hypothesis existed for almost 17 centuries, until anatomists proved that pigs and bulls have such a network, but not in humans.
In the era Middle ages all science in Europe, including anatomy, was subordinated to the Christian religion. Doctors of that time, as a rule, referred to the scholars of antiquity, whose authority was backed up by the church. At this time, no significant discoveries were made in anatomy. Dissection of corpses, autopsies, production of skeletons and anatomical preparations were prohibited. The Muslim East played a positive role in the continuity of ancient and European science. In particular, in the Middle Ages, doctors enjoyed the popularity of the books of Ibn Sipa (980-1037), known in Europe as Avicenna, the author of the "Canon of Medicine" containing important anatomical information.
Anatomists of the era Renaissance obtained permission to conduct autopsies. Thanks to this, anatomical theaters were created for performing public autopsies. The founder of this titanic work was Leonardo da Vinci, and the founder of anatomy as an independent science was Andrei Vesalius (1514-1564). Andrei Vesaliy studied medicine at the Sorbonne University and very soon realized the insufficiency of the then existing anatomical knowledge for practical activities doctor. The situation was complicated by the prohibition of the church on autopsies - the only source of study of the human body at that time. Vesalius, despite the real danger from the Inquisition, systematically studied the structure of man and created the first truly scientific atlas of the human body. To do this, he had to secretly dig up the freshly buried corpses of executed criminals and conduct his research on them. At the same time, he exposed and eliminated Galen's numerous mistakes, which laid the analytical period in anatomy, during which many descriptive discoveries were made. In his writings, Vesalius focused on the systematic description of all human organs, as a result of which he was able to discover and describe many new anatomical facts (Fig. 1.1).
Rice. 1.1. Drawing of the opened brain from the atlas of Andrei Vesalius (1543):
For his activities, Andrei Vesalius was persecuted by the church, was sent to repentance in Palestine, was shipwrecked and died on the island of Zante in 1564.
After the works of A. Vesalius, anatomy began to develop at a faster pace, in addition, the church was no longer so harshly pursued autopsy by doctors and anatomists. As a result, the study of anatomy has become an integral part of the training of doctors in all universities in Europe (Fig. 1.2).
Rice. 1.2. Rembrandt Harmenszoon van Rijn. Anatomy lesson by Dr. Tulpa (late 17th century):
Attempts to link anatomical structures with mental activity gave rise to such a science as phrenology at the end of the 18th century. Its founder, Austrian anatomist Franz Gal, tried to prove the existence of rigidly defined connections between the structural features of the skull and the mental characteristics of people. However, after some time, objective studies have shown the groundlessness of phrenological statements (Fig. 1.3).
Rice. 1.3. Drawing from the atlas of phrenology, depicting "mounds of secrecy, greed and gluttony" on the head of a person (1790):
The following discoveries in the field of CNS anatomy were associated with the improvement of microscopic technology. First, August von Waller proposed his method of Wallerian degeneration, which allows tracing the paths of nerve fibers in the human body, and then the discovery of new methods of staining the nervous structures of E. Golgi and S. Ramon-y-Cajal made it possible to find out that in addition to neurons in the nervous system, there is still a huge the number of auxiliary cells - neuroglia.
Remembering the history of anatomical studies of the central nervous system, it should be noted that such an outstanding psychologist as Sigmund Freud began his career in medicine precisely as a neurologist - that is, a researcher of the anatomy of the nervous system.
In Russia, the development of anatomy was closely associated with the concept of nervousism, which proclaims the predominant role of the nervous system in the regulation of physiological functions. In the middle of the 19th century, the Kiev anatomist V. Betz (1834-1894) discovered giant pyramidal cells (Betz cells) in the V layer of the cerebral cortex and revealed the difference in the cellular composition of different parts of the cerebral cortex. Thus, he laid the foundation for the doctrine of the cytoarchitectonics of the cerebral cortex.
A major contribution to the anatomy of the brain and spinal cord was made by the outstanding neuropathologist and psychiatrist V.M.Bekhterev (1857-1927), who expanded the study of the localization of functions in the cerebral cortex, deepened the reflex theory and created an anatomical and physiological basis for the diagnosis and understanding of the manifestations of nervous diseases ... In addition, V.M.Bekhterev discovered a number of brain centers and conductors.
At present, the focus of anatomical studies of the nervous system has moved from the macrocosm to the microcosm. Nowadays, the most significant discoveries are being made in the field of microscopy not only of individual cells and their organelles, but also at the level of individual biomacromolecules.
1.2. Research methods in anatomy
All anatomical methods can be roughly divided into macroscopic
, which study the whole organism as a whole, organ systems, individual organs or their parts, and on microscopic
, the object of which is the tissues and cells of the human body and cell organelles. In the latter case, anatomical methods merge with the methods of such sciences as histology (the science of tissues) and cytology (the science of the cell) (Fig. 1.4).
Rice. 1.4. The main groups of methods for studying the morphology of the central nervous system :
In turn, macroscopic and microscopic studies consist of a set of various methodological techniques that allow one to study various aspects of morphological formations in the nervous system as a whole, in individual parts of the nervous tissue or even in a single neuron. Accordingly, a set of macroscopic (Fig. 1.5) and microscopic (Fig. 1.6) methods for studying the morphology of the central nervous system can be distinguished.
Rice. 1.5. Macroscopic methods for studying the nervous system :
Rice. 1.6. Microscopic methods for studying the nervous system :
Since the task of anatomical research (from the point of view of psychology) is to identify the connections of anatomical structures with mental processes, several methods from the arsenal of physiology can be connected to the methods of studying the morphology (structure) of the central nervous system (Fig. 1.7).
Rice. 1.7. General Methods for CNS Physiology and Anatomy :
1.3. Anatomical terminology
For a correct understanding of the structures of the brain and spinal cord, it is necessary to know some elements of the anatomical nomenclature.
The human body is presented in three planes, respectively, horizontal, sagittal and frontal.
Horizontal
the plane runs, as its name suggests, parallel to the horizon, sagittal
divides the human body into two symmetrical halves (right and left), frontal
the plane divides the body into anterior and posterior parts.
Two axes are distinguished in the horizontal plane. If the object is closer to the back, then it is said to be located dorsally, if closer to the abdomen, it is said to be ventrally. If an object is located closer to the midline, to the plane of symmetry of a person, then it is spoken of as located medially, if further, then laterally.
In the frontal plane, two axes are also distinguished: medio-lateral and rostro-caudal. If the object is located closer to the lower part of the body (in animals - to the back, or tail), then it is referred to as caudal, and if to the upper (closer to the head), then it is located rostrally.
In the sagittal plane of a person, two axes are also distinguished; rostro-caudal and dorso-ventral. Thus, the interposition of any anatomical objects can be characterized by their interposition in three planes and axes.
Ministry of Education of the Republic of Belarus
Educational institution
"Belorussian State University informatics
and radio electronics "
Department of Engineering Psychology and Ergonomics
ANATOMY AND PHYSIOLOGY
CENTRAL NERVOUS SYSTEM
Toolkit
for students of specialty 1 -
"Engineering and psychological support of information technologies"
correspondence courses
Minsk BSUIR 2011
Introduction ………………………………………………………………………
Topic 1. The cell is the basic structural unit of the nervous system …… ..….
Topic 2. Synaptic impulse transmission. ………………………………… ..
Topic 3. The structure and functions of the brain …… .. …………………….… ..
Topic 4. The structure and functions of the spinal cord …………………………………
Topic 5. Endbrain, structure and functions ……………………………… ...
Topic 6. Motor centers ……………………………………………… ..
Topic 7. Autonomic nervous system …………………………………………
Topic 8. Neuroendocrine system ………… .. ……………………………… ..
Literature……………………………………………………………………….
INTRODUCTION
Studying the discipline "Anatomy and physiology of the central nervous system" − an important component of the basic training of specialists in systems engineers. The purpose of teaching this discipline is to acquire knowledge on the formation of the information system of the brain, the transmission of information to the central parts of the nervous system along the afferent pathways, as well as on its transmission and exit to the "periphery" along the efferent pathways. Therefore, this methodological manual gives an idea of the activity of the central nervous system (CNS) as a morphological and functional basis of neuropsychological processes; the structure and functions of the central nervous system, which is responsible for collecting, processing information, transmitting it to the higher parts of the cerebral cortex for making managerial decisions; − the main mechanisms that ensure human life (metabolism, thermoregulation, neurohumoral regulation, system genesis), which are responsible for the reliable functioning of human systems, are considered. After each topic under consideration, control questions are given for consolidation and self-control of knowledge by students. At the end of the manual, a list of tasks for the test is given. The literature contains a list of sources with rich illustrative material.
The knowledge gained in the future will serve as the basis for the study of subsequent disciplines of the natural science block (psychophysiology, psychology, etc.).
Topic 1. CELL - BASIC STRUCTURAL UNIT OF THE NERVOUS SYSTEM
The entire nervous system is divided into central and peripheral. The central nervous system (CNS) includes the brain and spinal cord. Nerve fibers radiate from them throughout the body. − peripheral nervous system. It connects the brain with the senses and with the executive organs. − muscles and glands.
Anatomy of the central nervous system studies the structure of it component parts... Physiology studies the mechanisms of their joint work.
All living organisms have the ability to respond to physical and chemical changes in environment... The stimuli of the external environment (light, sound, smell, touch, etc.) are converted by special sensitive cells (receptors) into nerve impulses − a series of electrical and chemical changes in the nerve fiber. Nerve impulses are transmitted through sensitive (afferent) nerve fibers in the spinal cord and brain. Here, the corresponding command pulses are generated, which are transmitted via motor (efferent) nerve fibers to the executive organs (muscles, glands). These executive bodies are called effectors.
The main function of the nervous system − integration of external influences with the corresponding adaptive response of the body.
The central nervous system consists of two types of nerve cells: neurons and glial cells, or neuroglia. The human brain is the most complex of all systems in the universe known to science. Weighing about 1250 g, the brain contains 100 billion nerve neurons, connected in an unusually complex network. Neurons are surrounded by an even greater number of glial cells, which form a supporting and nutritious basis for neurons - glia (Greek "glia" − glue), which performs many other functions that have not yet been fully studied. The space between nerve cells (intercellular space) is filled with water with salts, carbohydrates, proteins, fats dissolved in it. The smallest blood vessels − capillaries − are located in a network between nerve cells.
Methodical instructions
The functions of neurons are to process information, and therefore to perceive it, transmit it to other cells, and also encode this information. The neuron performs all these operations due to its special device.
Despite some variety in the shape of neurons, most of them have more a large part called body (soma), and several scions. Usually, one longer process is distinguished, called axon, and several thinner and shorter, but branching processes called dendrites... The neuron body size is 5-100 micrometers. The length of the axon can be many times the size of the body and reach 1 meter.
The functions of a neuron for processing information are distributed between its parts as follows. The dendrites and the cell body receive input signals. The cell body sums them up, averages them, combines and “makes a decision”: to transmit these signals further or not, that is, forms a response. The axon will transmit output signals to its endings (terminals). Axon terminals transmit information to other neurons, usually through specialized contact points called synapses... Signals transmitted by neurons are electrical in nature.
Depending on the balance of impulses received by the dendrites of an individual neuron, the cell is activated (or not), and it transmits an impulse along its axon to the dendrites of another nerve cell, with which its axon is connected. In a similar way, each of the 100 billion cells can connect to 100,000 other nerve cells.
The tightly adjacent bodies of nerve cells are perceived by the naked eye as "gray matter". Cells form folded sheets, such as the cerebral cortex, and combine them into clusters called nuclei and reticular structures. Under the microscope, you can clearly distinguish structural models different parts of the cerebral cortex. Axons, or "white matter", form the main trunks, or "fiber tracts" that connect the cell bodies. The sizes of nerve cells are from 20 to 100 microns (1 micron is equal to a millionth of a meter).
Among the glial cells are stellate cells (astrocytes), very large cells (oligodendrocytes) and very small cells (microglia). Stellate cells serve as a support for neurons, an intermediary between a neuron and a capillary for the transfer of nutrients, a reserve material for "repairing" damaged neurons. Oligodendrocytes form myelin − a substance that covers axons and promotes faster signal transmission. Microglia are necessary when and where the nervous system is affected. Microglial cells migrate to damaged areas and, turning into macrophages, like protective blood cells, destroy waste products. Myelin is formed from a glial cell coiled spirally around an axon.
Control questions:
1. What does CNS anatomy study?
2. What does the physiology of the central nervous system study?
3. What is referred to as the central nervous system, to the peripheral?
4. What is the main function of the nervous system?
5. Name the types of nerve cells and indicate their ratio in the central nervous system.
6. What are the structure and functions of a neuron?
7. Name the types and functions of glial cells.
8. What are “gray matter” and “white matter”?
Topic 2. SYNAPTIC PULSE TRANSMISSION
Synapses on a typical neuron in the brain are either exciting, or brake, depending on the type of mediator released in them. Synapses can also be classified by their location on the surface of the receiving neuron — on the cell body, on the stem or spine of a dendrite, or on an axon. Depending on the mode of transmission, chemical, electrical and mixed synapses are distinguished.
Methodical instructions
The process of chemical transfer goes through a number of stages: synthesis of a mediator, its accumulation, release, interaction with the receptor and termination of the action of the mediator. Each of these stages has been characterized in detail, and drugs have been found that selectively enhance or block a particular stage.
Neurotransmitter(neurotransmitter, neurotransmitter) is a substance that is synthesized in a neuron, is contained in the presynaptic endings, is released into the synaptic cleft in response to a nerve impulse and acts on special areas of the postsynaptic cell, causing changes in the membrane potential and cell metabolism. For a long time, it was believed that the function of a neurotransmitter is only to open (or even close) ion channels in the postsynaptic membrane. It was also known that the same substance can always be released from the terminal of one axon. Later, new substances were discovered that appear in the synapse area at the time of the transfer of excitation. They were named neuromodulators... The study of the chemical structure of all detected mediators and neuromodulators clarified the situation. All studied substances related to synaptic transmission of excitation were divided into three groups: amino acids, monoamines and peptides... All these substances are now called mediators.
There are "neuromodulators" that do not have an independent physiological effect, but modify the effect of neurotransmitters. The action of neuromodulators has a tonic character - slow development and long duration of action. Its origin is not necessarily neural, for example, glia can synthesize a number of neuromodulators. The action is not initiated by a nerve impulse and is not always associated with the effect of a mediator. The target of the impact is not only receptors on the postsynaptic membrane, but different parts of the neuron, including intracellular ones.
Per last years After a new class of chemical compounds, neuropeptides, was discovered in the brain, the number of known systems of chemical messengers in the brain increased dramatically. Neuropeptides represent chains of amino acid residues. Many of them are located at the axonal endings. Neuropeptides differ from previously identified mediators in that they organize such complex phenomena as memory, thirst, libido, etc.
Control questions:
1. What is a synapse?
2. Name the types of synapses.
3. What is characteristic of electrical synaptic transmission?
4. What is characteristic of chemical signal transmission?
5. Give the definition of a neurotransmitter. What groups are synaptic mediators divided into according to their chemical structure?
6. What are neuromodulators? What is their origin and action?
7. What are neuropeptides?
Topic 3. STRUCTURE AND FUNCTIONS OF THE BRAIN
In latin brain denoted by the word "Cerebrit", and in ancient Greek - "Encephalon". The brain is located in the cranial cavity and has a shape, in general outline corresponding to the internal outlines of the cranial cavity.
There are three large parts in the brain: cerebral hemispheres, or hemispheres, cerebellum and brain stem.
The largest part of the entire brain is occupied by the cerebral hemispheres, followed by the cerebellum in size, the rest is the brain stem. Both hemispheres, left and right, are separated from each other by a slit. In its depths, the hemispheres are interconnected by a large adhesion - the corpus callosum. There are also two not so massive adhesions, including the so-called anterior commissure.
From the side of the lower surface of the brain, not only the lower side of the cerebral hemispheres and cerebellum is visible, but also the entire lower surface of the brain stem, as well as the cranial nerves extending from the brain. Mainly the cerebral cortex is visible from the side.
Methodical instructions
Vital important processes stop if any vital center of the brain is destroyed: cardiovascular or respiratory. If we compare hierarchically these centers with the corresponding higher and lower centers (in the spinal cord), then they can be called the main organizers of blood circulation and respiration. The spinal cord, that is, its motoneurons that go directly to the muscles, is the performer. And in the role of initiator and modulator - the hypothalamus (diencephalon) and cerebral cortex (telencephalon).
The medulla oblongata contains cardiovascular center... The cardiovascular center includes the nucleus of the vagus nerve, which has parasympathetic effects on the heart, and the so-called vasomotor center, which has sympathetic effects on the heart and blood vessels. In the vasomotor center, two zones are distinguished: pressor (vasoconstriction) and depressor (vasodilatation), which are in reciprocal relationships. The pressor zone is “switched on” from the chemoreceptors (they react to the blood composition) and exteroreceptors, and the depressor zone from the baroreceptors (they react to the pressure exerted by the walls of the vessels). Hierarchically, the highest center of parasympathetic and sympathetic innervation is the hypothalamus. It depends on it what effects will occur in the cardiovascular system. The hypothalamus determines this in accordance with the actual need of the whole organism at a given moment.
Respiratory center partly located in the pons of the hindbrain and partly in the medulla oblongata. We can say that there is a separate center for inhalation (in the bridge) and an exhalation center (in the medulla oblongata). These centers are in a reciprocal relationship. Inhalation occurs with the contraction of the external intercostal muscles, and exhalation - with the contraction of the internal intercostal muscles. Commands to the muscles come from the motor neurons of the spinal cord. Commands go to the spinal cord from the centers of inhalation and exhalation. The center of inspiration is characterized by constant impulse activity. But it is interrupted by information coming from stretch receptors, which are located in the walls of the lungs. Expansion of the lungs from inhalation initiates exhalation. The respiratory rate can be modulated by the vagus nerve and the higher centers: the hypothalamus and cerebral cortex. For example, when speaking, we can consciously regulate the duration of inhalation and exhalation, since we are forced to pronounce sounds of different duration.
In addition, the medulla oblongata contains the nuclei of several cranial nerves. In total, a person has 12 pairs of cranial nerves, of which four pairs are located in the medulla oblongata. These are the hypoglossal nerve (XII), accessory (XI), vagus (X) and glossopharyngeal (IX) nerve. Thanks to the nuclei of the glossopharyngeal nerve, movements of the pharyngeal muscles occur, which means that several reflexes are realized that are important for the body: coughing, sneezing, swallowing, vomiting, and phonation also occurs - the pronunciation of speech sounds. In this regard, it is believed that the corresponding centers are located in the medulla oblongata: sneezing, coughing, vomiting.
In addition, the vestibular nuclei are located in the medulla oblongata, which regulate the function of balance.
TO hindbrain include the Varoliev pons and the cerebellum. The cavity of the hindbrain is the fourth cerebral ventricle (as an ongoing and expanding spinal canal). The Varoliev Bridge is formed by powerful conductive paths. The cerebellum is a motor center with numerous connections to other parts of the brain. The binder fibers are bundled and form three pairs of legs. The lower legs provide a connection with the medulla oblongata, the middle ones - a connection with the bridge, and through it - with the cortex, and the upper ones - with the midbrain.
The cerebellum makes up only 10% of the mass of the brain, but includes more than half of all neurons in the central nervous system. The motor functions of the cerebellum are to regulate muscle tone, body posture and balance. The ancient cerebellum is responsible for this. . The cerebellum coordinates posture and targeted movements. The old and new cerebellum are responsible for this. . The cerebellum is also involved in the programming of various purposeful movements, which include ballistic movements, sports movements, such as throwing a ball, playing on musical instruments, "Blind" method of typing, etc. The assumption about the participation of the cerebellum in the processes of thinking is studied: the presence of common neural systems for controlling movement and thinking is discussed.
At the bottom of the cerebral ventricle, which has a rhomboid shape (it is also called a rhomboid fossa), there are the nuclei of the vestibulocochlear (VIII), facial (VII), abducens (VI) and partially trigeminal (V) cranial nerves.
Midbrain is a very constant, evolutionarily unchanging part of the brain. Its nuclear structures are associated with the regulation of postural movements (red nucleus), with participation in the activity of extrapyramidal motor system(substantia nigra and red nucleus), with indicative reactions to visual and sound signals (quadruple). The superior colliculus is the primary visual center, and the inferior colliculus is the primary auditory center.
The so-called Sylvian aqueduct passes through the midbrain, connecting the 4th and 3rd cerebral ventricles to each other. Here are the nuclei of the 3rd (oculomotor), 4th (block) and one of the nuclei of the 5th (trigeminal) cranial nerves. The 3rd and 4th cranial nerves regulate eye movements. Considering that the upper colliculus is also located here, which receives information from vision receptors, the midbrain can be considered a place of concentration of visual-oculomotor functions.
Diencephalon represented by one formation - the thalamus. The thalamus has a rounded ovoid shape. The historical name of the thalamus is the visual hillock, or the sensitive hillock. It got this name because of its main function, which it managed to establish a very long time ago. The thalamus is the collector of all sensory information. This means that it receives information from all types of receptors, from all senses (sight, hearing, taste, smell, touch), proprioceptors, interoreceptors, vestibuloreceptors.
Instead of the name "diencephalon", the name "thalamus" is often used. The thalamus occupies the central part of the diencephalon. It forms the bottom and walls of the 3rd cerebral ventricle. Anatomically, the thalamus has appendages: the superior appendage (epithalamus) , inferior appendage (hypothalamus) , posterior part (metathalamus) , and optic chiasm. or visual chiasm.
Epithalamus consists of several entities. The biggest is pineal gland, or the pineal gland (pineal gland). It is an endocrine gland that secretes melatonin. Norepinephrine, histamine and serotonin are also found in the pineal gland. The participation of these substances in the regulation of circadian rhythms (circadian rhythms of activity associated with illumination) has been proven.
Metathalamus consists of lateral geniculate bodies (secondary visual centers) and medial geniculate bodies (secondary auditory center).
Hypothalamus is at the same time the highest center of the autonomic nervous system, a "chemical analyzer" of the composition of blood and cerebrospinal fluid, and an endocrine gland. It is part of the limbic system of the brain. Part of the hypothalamus is pituitary- education the size of a pea. The pituitary gland is an important endocrine gland: its hormones regulate the activity of all other glands.
Due to the fact that the hypothalamus has its own various osmo - and chemoreceptors, it can determine the sufficiency of the concentration of various substances in the body fluids passing through the hypothalamic tissue - blood and cerebrospinal fluid. In accordance with the result of the analysis, it can enhance or weaken various metabolic processes both by sending nerve impulses to all vegetative centers, and by releasing biologically active substances - liberins and statins. So, the hypothalamus is the highest regulator of food, sexual, aggressive-defensive behavior, that is, the main biological motivations.
Since the hypothalamus is part of limbic system, it is also the center of integration of somatic (associated with motor responses in accordance with the data of the senses) and autonomic functions, namely: it provides somatic functions in accordance with the needs of the whole organism. For example, if for the body at a given moment, a biologically important task is defensive behavior, which, first of all, depends on the effective work of skeletal muscles and sensory organs (see, hear, move). But the effective work of muscles, in turn, depends not only on the speed of nerve impulses, but also on the provision of muscles and nerves with energy resources and oxygen, etc. Therefore, we can say that the hypothalamus provides "internal" support for "external" behavior.
The thalamic nuclei are functionally divided into three groups: relay (switching), associative (integrative) and nonspecific (modulating).
Switch cores- This is an intermediate link in long pathways (afferent pathways), coming from all receptors in the trunk, limbs and head. Further, these afferent signals are transmitted to the corresponding analyzer zones of the cerebral cortex. It is this part of the thalamus that is the “sensitive hillock”. This functionally includes both the lateral and medial geniculate bodies, since from them information is switched to the occipital and temporal cortex, respectively.
The associative nuclei of the thalamus connect different nuclei within the thalamus itself, as well as the thalamus itself, with the associative zones of the cerebral cortex. Thanks to these connections, for example, it is possible to form a "body scheme", flow of various kinds gnostic (cognitive) processes, when a word and a visual image are linked together.
Nonspecific nuclei of the thalamus form the most evolutionarily ancient part of the thalamus. it reticular nucleus... They receive sensory information from all the ascending pathways and from the motor centers of the midbrain. The cells of the reticular formation are not able to distinguish which modality the signal is coming in. But it is in this way that she comes into a state of excitement, as if "infected" with energy and, in turn, exerts a modulating effect on the cerebral cortex, namely, activating attention. Therefore it is called reticular activating system of the brain.
In the diencephalon is the optic nerve, or the 2nd cranial nerve, starting from the receptors of the retina of the eye. Here, on the “territory” of the diencephalon, the optic nerve makes a partial intersection and further continues as the optic tract leading to the primary and secondary visual centers, and then to the visual cortex of the brain.
Control questions:
1. What are the main parts of the brain.
2. Where is the medulla oblongata located and what is it?
3. Name the functions of the medulla oblongata.
4. What is the hindbrain and what are its functions?
5. What is the midbrain and what are its functions?
6. What is the diencephalon?
7. What is the structure and purpose of the epithalamus?
8. What is the structure and purpose of the metathalamus?
9. What is the structure and purpose of the hypothalamus?
10. Describe each of the three groups of thalamic nuclei.
Topic 4. STRUCTURE AND FUNCTIONS OF THE SPINAL CORD
The spinal cord is located in the vertebral canal. It is approximately cylindrical in shape. Its upper end passes into the medulla oblongata, and the lower end into the terminal thread (cauda equina).
In an adult, the spinal cord begins at the upper edge of the first cervical vertebra and ends at the level of the second lumbar vertebra. The spinal cord has a segmental structure. It has 31 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal. (Sometimes they say that there are 31-33 segments in total, and 1-3 in the coccygeal region. The fact is that the coccygeal vertebrae are fused into one).
Each segment is designated by the vertebra near which its roots come out. But this does not mean that each segment is located exactly opposite the corresponding vertebra. In the embryonic state, the length of the spinal cord is approximately equal to the length of the spine. But in the process of individual development, the spine grows faster than the brain. As a result, the spinal cord is shorter than the spine. Therefore, in the upper parts of the spinal cord, the segments correspond to the vertebrae, and their roots come out in the same place, horizontally. In the lower parts, the spinal canal no longer contains medulla, and the segments corresponding to the vertebrae are located higher. Therefore, at the bottom, the roots in the form of a bundle (cauda equina) go down to the intervertebral foramen and then leave the spine.
Methodical instructions
The spinal cord is covered with three membranes. The outer meninges are called solid. The middle shell is called cobweb... The space between these shells is called subdural... The inner shell is called vascular. The space between the arachnoid and choroid is called subarachnoid or subarachnoid... The choroid and arachnoid membranes form the pia mater of the brain. The spaces between the membranes are filled with cerebrospinal fluid (CSF). CSF is synonymous with cerebrospinal fluid and cerebrospinal fluid. .
The spinal cord and brain share the same membranes and communicating spaces between the membranes. In addition, the central canal of the spinal cord continues into the brain. Expanding, it forms the ventricles of the brain - cavities also filled with cerebrospinal fluid.
The meninges and cerebrospinal fluid protect the spinal cord from mechanical damage. Cerebrospinal fluid also serves to chemically protect brain tissue from harmful substances. CSF is formed by filtration from arterial blood in the choroid plexus of the 4th and lateral ventricles of the brain, and its outflow occurs into the venous blood in the region of the 4th ventricle. Various substances, which easily enter the bloodstream from the digestive tract, cannot easily penetrate into the cerebrospinal fluid due to blood-brain barrier, which works as a filter, selecting useful and "discarding" substances harmful to the central nervous system.
Control questions:
1. Describe the longitudinal structure of the spinal cord and its location.
2. What membranes surround the spinal cord, what are their functions?
3. What is cerebrospinal fluid, where is it located and what are its functions?
4. What is the function of the blood-brain barrier?
Topic 5. FINAL BRAIN, STRUCTURE AND FUNCTIONS
The terminal brain anatomically consists of two hemispheres, connected by the corpus callosum , fornix and anterior commissures. Each hemisphere functionally and anatomically consists of a cortex and subcortical (basal) nuclei. In the thickness of the cerebral hemispheres are the cavities of the 1st and 2nd cerebral ventricles, which have a complex configuration. These ventricles are also called the anterior (l-th) and posterior (2nd) ventricles of the telencephalon.
The subcortical nuclei of the telencephalon include, firstly, three paired formations included in the striopallidal system, which is important in the regulation of movements: the caudate nucleus, the pallidum , fence . The striopallidal system is part of the extrapyramidal motor system.
Secondly, the “subcortex” includes the amygdala and the nucleus of the transparent septum and other formations. The functions of these nuclei are associated with the regulation of complex forms of behavior and mental functions, such as instincts, emotions, motivation, memory.
Most often, the above subcrustal nuclei, or basal nuclei, that is, those located at the base of the cortex, as the foundation of a house, are simply called "subcortex". But sometimes the subcortex is called everything that is below the cortex, but above the brain stem, and then the thalamus with its appendages is also referred to it.
In general, the subcortical structures perform integrative functions.
In the brain, as in the spinal cord, there are three types of substances: gray, white and mesh... Accordingly, the first is formed by the bodies of neurons, the second is formed by myelinated processes of neurons, collected in ordered bundles, and the third is formed by alternating bodies and processes going in different directions.
The reticular substance, or reticular formation, is located more centrally. The bodies of neurons (gray matter) are located in clusters called nuclei. Sometimes the word knot or ganglion is used instead of the word "nucleus". Bundles of myelinated fibers, as in the spinal cord, form pathways: short and long. Short paths are of two types - commissural and associative.
Methodical instructions
The cranial nerves are analogous to the spinal nerves. In humans, 12 pairs of cranial nerves are distinguished. They are usually denoted by Roman numerals, and each has its own name and function.
The function of the spinal nerves is to transmit information from receptors located in various parts of the body to the central nervous system (through the dorsal roots of the spinal cord) and transmit information from the central nervous system to the muscles that carry out body movements, the muscles of internal organs and glands (through the anterior roots spinal cord). Similar to the spinal nerves, the cranial nerves transmit information from receptors located in the head region (sensory organs) to the brain stem and transmit information from the brain centers to the muscles and glands located in the head region.
Another analogy is observed. The spinal nerves that control the skeletal muscles of the trunk are influenced by the higher motor centers of the brain. Likewise, the cranial nerves that control the skeletal muscles of the head are subject to the influences of the cortical motor zones, thanks to which voluntary movements of the tongue, nose, ear, eyes, eyelids, etc. are possible.
Thus, the cranial nerves are peripheral nerves that do not belong to the central nervous system. It seems incredible, but this is how it is. It's just that everything in the head area - both the center (brain) and the periphery (receptors and cranial nerves) are geographically close to each other. It is because of this that the clear segmentation that is observed in the spinal nerves is violated, when the sensory nerve roots are strictly on the posterior surface, and the motor roots on the anterior surface of the spinal cord. Moreover, some cranial nerves generally have either only a sensory branch (optic nerve) or only a motor (oculomotor nerve).
To those organs (muscles, glands) that are outside the skull, as well as from receptors located outside the skull, the cranial nerves pass through certain openings of the skull: jugular, occipital, temporal, ethmoid openings.
Reticular formation(RF) - reticular substance is an accumulation of nerve cells that forms a network of densely intertwined processes going in different directions. The reticular formation is located in the central part of the brain stem and in separate inclusions in the diencephalon. RF cells are not directly associated with the ascending pathways from receptors to the cortex. But all sensory pathways ascending to the cortex send their branches to the RF. This means that the RF receives as many impulses as the higher centers, although it does not distinguish between them "by origin." But thanks to them, a constantly high level of excitation in the cells of the RF is maintained. In addition, RF excitation depends on the concentration of chemicals (humoral factors) in the CSF. Thus, the RF serves as an accumulator of energy, which it directs mainly to increase the activity, that is, the level of wakefulness, of the cortex. However, RF has an activating effect in the downward direction: by controlling the reflexes of the spinal cord through the reticulospinal tracts, changing the activity of alpha and gamma motor neurons of the spinal cord.
Control questions:
1. Describe the structure and location of the telencephalon.
2. Name three types of substances that make up the brain.
3. Describe the structure and location of the reticular formation.
4. What are the functions of the reticular formation?
Topic 6. MOTOR CENTERS
All motor functions (or simply movements) can be divided into two types: purposeful and posnotonic.
Purposeful movements- these are movements aimed at some goal associated with movement in space; these are labor movements associated with the need to take, lift, hold, release, etc. These are various manipulative movements that a person learns throughout life. These are mainly voluntary movements. Although the defensive flexion reflex can also be called purposeful, since it has the goal of breaking off contact with a painful stimulus.
Poznotonic movements, or postural, provide the usual for this organism position in space, that is, in the gravitational field of the Earth. For a person, this is an upright position. Postural movements are based on innate reflex reactions. The name "postural" comes from english word "Posture", which means "pose, figure".
The structures of the central nervous system responsible for the nervous regulation of motor functions are called motor centers... They are localized in various parts of the central nervous system.
The motor centers that regulate postural movements are concentrated in the structures of the brain stem. The motor centers that control purposeful movements are located at higher levels of the brain - in the cerebral hemispheres: subcortical and cortical centers.
Methodical instructions
The brain stem includes the medulla oblongata, part of the hindbrain and midbrain. The following motor centers are located at the level of the medulla oblongata: the vestibular nuclei and the reticular formation. Vestibular nuclei receive information from balance receptors located in the vestibule of the inner ear , and in accordance with it, excitatory signals are sent to the spinal cord through the vestibulospinal tract. The impulses are intended for the extensor muscles of the trunk and limbs, thanks to the work of which a slipped or stumbled person is able to immediately react: to straighten up, to find support again, that is, to restore balance. From reticular formation the medulla oblongata also begins the lateral reticulospinal pathway, which innervates the maximally located flexor muscles of the trunk and limbs.
The main motor function of the medulla oblongata–maintaining balance automatically, without the participation of consciousness.
In the Varolievy pons of the hindbrain, there are the nuclei of the reticulospinal tract, which excites the motor neurons of the extensors. This means that the data and the vestibulospinal centers act "at the same time".
In the midbrain, several nerve centers are related to the regulation of movements: the red nucleus, the roof of the brain, or the quadruple, the substantia nigra , as well as the reticular formation.
From red kernel the rubrospinal tract begins. Thanks to the impulses transmitted along this path, body posture is regulated, for which the red nucleus is credited with the role of the main antigravitational mechanism. The red core increases the tone of the flexors of the upper extremities and ensures coordination of various muscle groups (this is called synergy) when walking, jumping, and climbing. However, the red nucleus itself is constantly under the control of higher centers in relation to it - subcortical, or basal nuclei.
Quadruple consists of the upper and lower colliculus, which are simultaneously not only the motor centers, but also the primary centers of vision (upper colliculus) and hearing (lower colliculus). From them, the tectospinal tracts begin, along which, in accordance with visual and auditory information, a command is transmitted to turn the neck or eyes and ears in the direction of a perceived new stimulus for a given environment. This reaction is called the orientation reflex, or the "what is it?"
Substance black has synaptic connections with the basal subcortical nuclei. At these synapses, the mediator is dopamine. With its help, the substantia nigra has an exciting effect on the basal ganglia.
Reticulospinal tract, starting from the reticular formation of the midbrain, has an exciting effect on gamma-motor neurons of all muscles of the trunk and proximal extremities.
Cerebellum, like the motor centers of the brain stem, provides skeletal muscle tone, regulation of poznotonic functions, coordination of poznotonic movements with purposeful ones. The cerebellum has two-way connections with the cerebral cortex, and therefore it is a corrector of all types of movements. It calculates the amplitude and trajectory of movements.
TO basal ganglia, or nuclei, include several subcortical structures: the caudate nucleus, the fence and the pallidum. Another name for this complex is the striopallidal system. This system is part of an even more complex motor system - extrapyramidal. Basal ganglia mainly perform the functions of controlling rhythmic movements, ancient automatisms (walking, running, swimming, jumping). They also create a backdrop that facilitates specialized movements and also provides accompanying movements.
The higher motor centers are located in the neocortex of the cerebral hemispheres. The motor centers of the cortex have a specific localization: this precetral gyrus, located in front of the central Rolland furrow. Their localization was established experimentally by electrical stimulation of various points of the motor zone. When certain points were stimulated, movements of the contralateral limb were obtained. According to modern ideas, in the cortex, not individual muscles are represented, but whole movements performed by the muscles. grouped around a specific joint. The motor cortex itself contains “higher order” motor neurons, or command neurons, which activate various muscles. This motor zone is called the primary motor zone. Adjacent to it is a secondary motor zone, which is called premotor. Its functions are associated with the regulation of motor functions of a social nature, for example, writing and speaking. It is from here, from these motor zones, that both pyramidal descending tracts originate.
The higher motor centers are adjacent to the higher sensory centers, which are located in postcentral gyrus. Sensory areas(zones) receive information from skin receptors and proprioceptors located on all parts of the body. Here, similarly to the motor zones, all parts of the body and face are represented. Therefore, the postcentral area of the cortex is called somatosensory. However, the size of the representations does not depend on the size of the body part itself, but on the importance of the information coming from it. Therefore, the representation of the trunk and lower limb is relatively small, but the representation of the hand is huge.
It has been shown that the motor and sensory areas partially overlap; therefore, both zones are called in one word - the sensorimotor zone.
Control questions:
1. How are movements classified?
2. Name the stem and subcortical motor centers.
3. What are the functions of the red nucleus?
4. What are the functions of the quadruple?
5. What are the functions of the substantia nigra?
6. What are the functions of the basal ganglia?
7. Specify the location and name the functions of the sensorimotor centers.
Topic 7. VEGETATIVE NERVOUS SYSTEM
The nervous system is usually divided into somatic and autonomic. In tasks somatic system includes a response to external signals and, in accordance with the data of the sense organs, the implementation of motor reactions. For example, the task of avoiding the source of unpleasant, harmful influences and approaching the sources of pleasant, useful influences.
The name of the somatic nervous system comes from the word "soma", which means "body" in Latin. The body is not only in the cell, but also in our microorganism - this is our entire muscular membrane, consisting of skeletal (striated muscles), thanks to which the body is able to perform movements.
Methodical instructions
Autonomic nervous system(autonomic nervous system, visceral nervous system) - a division of the nervous system that regulates the activity of internal organs, glands of internal and external secretion, blood and lymph vessels. The autonomic nervous system regulates the state of the internal environment of the body, controls the metabolism and the associated functions of respiration, blood circulation, digestion, excretion and reproduction. The activity of the autonomic nervous system is mostly involuntary and is not directly controlled by consciousness. The main effector organs of the autonomic system are the smooth muscles of the internal organs, blood vessels and glands.
Vegetative and somatic parts of the nervous system act in a friendly manner. Their neural structures cannot be completely separated from each other. Therefore, such a division is analytical, since skeletal muscles and internal organs are simultaneously involved in the body's reactions to various stimuli (if only because they provide muscle work).
The vegetative and somatic systems have the following differences: in the location of their centers; in the device of their peripheral departments; in the features of nerve fibers; depending on consciousness.
There are two functional divisions of the autonomic nervous system: segmental-peripheral providing autonomic innervation of individual body segments and related internal organs, and central (suprasegmental) carrying out the integration, unification of all segmental apparatuses, the subordination of their activities to the general functional tasks of the whole organism.
At the segmental-peripheral level of the autonomic nervous system, there are two relatively independent parts of it - sympathetic and parasympathetic, the coordinated activity of which provides fine regulation of the functions of internal organs and metabolism. Sometimes the influence of these parts or systems on an organ is opposite in effect, and an increase in the activity of one system is accompanied by an inhibition of the activity of another. In the regulation of some other functions, both systems act unidirectionally.
Sympathetic segmental spinal centers are located in the lateral horns of the thoracic and lumbar spinal cord. From the cells of these centers, vegetative fibers originate, heading to the sympathetic nodes or vegetative ganglia (preganglionic fibers). The ganglia are located in chains on both sides of the spine, making up the so-called sympathetic trunks, in which there are 2-3 cervical, 10-12 chest nodes, 4-5 lumbar, 4-5 sacral nodes. The right and left trunks at the level of the I coccygeal vertebra are connected and form a loop, in the middle of which there is one unpaired coccygeal node. Postganglionic fibers depart from the nodes, going to the innervated organs. Part of the preganglionic fibers, without interruption in the ganglia of the sympathetic trunks, reaches the celiac and inferior mesenteric vegetative plexuses, from the nerve cells of which postganglionic fibers extend to the innervated organ.
Parasympathetic nerve centers are located in the autonomic nuclei of the brain stem, as well as in the sacral part of the spinal cord, from where the parasympathetic preganglionic fibers begin; these fibers end in vegetative nodes located in the wall of the working organ or in the immediate vicinity of it, and therefore the postganglionic fibers of this system are extremely short. From the autonomic centers located in the brain stem, parasympathetic fibers pass through the oculomotor, facial, glossopharyngeal and vagus nerves. They innervate the smooth muscles of the eye (except for the muscle that dilates the pupil, which receives innervation from the sympathetic part of the autonomic nervous system), the lacrimal and salivary glands, as well as the vessels and internal organs of the chest and abdominal cavity... The sacral parasympathetic center provides segmental autonomic innervation Bladder, sigmoid colon and rectum, genitals.
An increase in the activity of the sympathetic nervous system is accompanied by an expansion of the pupil, an increase in pulse rate and an increase in blood pressure, dilation of the small bronchi, a decrease in intestinal motility and a contraction of the sphincters of the bladder and rectum. An increase in the activity of the parasympathetic system is characterized by a constriction of the pupil, a slowdown in heart contractions, a decrease in blood pressure, spasm of small bronchi, increased intestinal motility and relaxation of the sphincters of the bladder and rectum. The consistency of the physiological influences of these systems provides homeostasis- harmonious physiological condition organs and the body as a whole at an optimal level.
The activity of sympathetic and parasympathetic segmental-peripheral formations is under control central suprasegmental autonomic apparatus, which include the respiratory and vasomotor stem centers, the hypothalamic region and the limbic system of the brain. On defeat respiratory and vasomotor stem centers breathing disorders and cardiac activity occur. Kernels hypothalamic region regulate cardiovascular activity, body temperature, work gastrointestinal tract, urination, sexual function, all types of metabolism, the endocrine system, sleep, etc. The nuclei of the anterior hypothalamic region are associated mainly with the function of the parasympathetic system, and the posterior - with the function of the sympathetic system. Limbic system not only takes part in the regulation of the activity of vegetative functions, but largely determines the vegetative "profile" of an individual, his general emotional and behavioral background, performance and memory, providing a close functional relationship of the somatic and vegetative systems.
Limbic the system is a functional association of brain structures involved in the organization of emotional-motivational behavior, such as food, sexual, defensive instincts. This system is involved in organizing the wakefulness-sleep cycle.
Control questions:
1. What are the tasks of the somatic nervous system?
2. What are the tasks of the autonomic nervous system?
3. What are the main differences between the somatic and autonomic parts of the nervous system.
4. What is the simatic nervous system?
5. How is the increase in the activity of the sympathetic nervous system manifested?
6. What is the parasymatic nervous system?
7. How is the increase in the activity of the parasympathetic nervous system manifested?
8. What is homeostasis?
9. Which centers control the activity of the sympathetic system, and which - the parasympathetic?
10. Is it true that the somatic and autonomic parts of the nervous system act completely independently of each other? Give reasons for your answer.
Topic 8. NEUROENDOCRINE SYSTEM
Endocrine, or according to modern data, neuroendocrine system regulates and coordinates the activity of all organs and systems, ensuring the adaptation of the organism to the constantly changing factors of the external and internal environment, the result of which is the maintenance of homeostasis, which, as you know, is necessary to maintain the normal vital activity of the organism. In recent years, it has been clearly shown that the neuroendocrine system performs these functions in close interaction with the immune system.
Methodical instructions
The endocrine system is presented endocrine glands responsible for the formation and release of various hormones into the bloodstream.
It has been established that the central nervous system (CNS) takes part in the regulation of the secretion of hormones of all endocrine glands, and hormones, in turn, affect the function of the central nervous system, modifying its activity and state. Nervous regulation of the endocrine functions of the body is carried out both through hypophysotropic (hypothalamic) hormones, and through the influence of the autonomic (autonomic) nervous system. In addition, a sufficient amount of monoamines and peptide hormones are secreted in various areas of the central nervous system, many of which are also secreted in the endocrine cells of the gastrointestinal tract.
Endocrine function of the body provide systems that include: hormone secreting endocrine glands; hormones and their transport routes, corresponding target organs or tissues, which respond to the action of hormones and are provided with normal receptor and post-receptor mechanisms.
The endocrine system of the body as a whole maintains constancy in the internal environment, which is necessary for the normal course of physiological processes. In addition, the endocrine system, together with the nervous and immune systems, provide reproductive function, growth and development of the body, the formation, utilization and storage ("in reserve" in the form of glycogen or fatty tissue) energy.
Mechanism of action of hormones
Hormone Is a biologically active substance. This is a chemical informative signal that can cause violent changes in the cell. The hormone, like other informative signals, binds to the membrane receptors of cells. But unlike those signals that open ion channels in the membrane, the hormone "turns on" a chain (cascade) of chemical reactions that begin on the upper surface of the membrane, continue on its inner surface, and end deep inside the cell. One of the links in this chain of reactions are the so-called second mediators. Second intermediaries- these are "biological amplifiers" of biochemical processes. In all living organisms, from humans to unicellular organisms, only two second mediators are known: cyclic adenosine monophosphoric acid (CAMP) and inositol triphosphate (IF-3). Calcium (Ca) is also referred to as the second mediators. Thus, the second mediator is an intermediary in the transmission of an informative signal from the hormone to the internal systems of the cell. ( The first intermediaries Are synaptic mediators known to us).
In the life of animals and humans, from time to time there is a state of psychoemotional stress. It arises under the action of three factors: the uncertainty of the situation (it is difficult to determine the probability of events, it is difficult to make a decision), the lack of time, the significance of the situation (to satisfy hunger or save a life?).
Psycho-emotional stress (stress) is accompanied by both subjective experiences and physiological changes in all body systems: cardiovascular, muscular, endocrine.
At the onset of stress, the hypothalamus nervously (sympathetic nervous system, nerve impulse) stimulates the release of adrenaline (anxiety hormone) from the adrenal glands. Adrenaline enhances muscle and brain nutrition: transfers from fat depots to the blood fatty acid(for muscle nutrition), and from liver glycogen transfers glucose into the blood (for brain nutrition). But this is energetically not beneficial to the body during prolonged stress, because the muscle can "eat" glucose, without leaving it for the brain.
Therefore, at the next stage of stress, the pituitary gland secretes ACTH (adrenocorticotropic hormone) and stimulates the release of cortisol from the adrenal cortex. Cortisol interferes with the absorption of glucose into muscle tissue. In addition, cortisol activates the conversion of protein to glucose. This is important because glycogen stores are low. But where does protein come from? (Remember that during stress, all digestion processes are inhibited.) There is a lot of structural protein in the body - all cells are made of protein. But if you transfer it to "fuel", that is, turn it into glucose, then you can destroy the entire body. Therefore, protein is taken from those tissues of the body that are rapidly renewed, without which you can temporarily do without. Such tissue is lymphocytes, that is, the protective cells of the body, and their protein is converted into glucose. But such rescue from stress has side negative effects, namely, after prolonged stress it is easy to get colds and viral diseases, Cortisol inhibits the activity of the "reproductive" centers of the hypothalamus. Therefore, with prolonged stress (negative emotions), women have disorders menstrual cycle, and in men - violation of sexual potency.
Control questions:
1. What processes is the neuroendocrine system responsible for?
2. What does the neuroendocrine system consist of?
3. What groups are the glands divided into and by what principle?
4. Give a definition to the concept of "hormone" and describe the mechanism of action of hormones.
5. Name the factors contributing to the onset of a state of psychoemotional stress.
6. Describe the hormonal mechanism of stress.
Tasks for the test
1. Subject and methods of research of higher nervous activity (HND). Teaching about the features of GNI in humans and animals.
2. The human brain as a system of systems. Types of brain activity. The main functions of the human brain in the process of its phylogenesis.
3. Nervous system, anatomical structure, departments and types, nerve connections, sources of formation of information transmission energy.
4. The structure of the brain, regions, parts of the brain: thalamus, hypothalamus, diencephalon, their topography, functional connections.
5. Organization of the nervous system. The structure of neurons, its functions. Neural connections in the transmission of information. Auxiliary systems.
6. The concept of "synapse", its function and role in the transmission of information. Features of synapses different levels nerve connections.
7. Glial cells serving neurons, their role and functions in the maintenance of the entire central nervous system. Formation of pathways in the transmission of information.
8. Classification of nerve centers according to their functional characteristics. Afferent and efferent divisions. Their difference in communication functions.
9. Integrated activity of the spinal cord and medulla oblongata. Topography, structure, functions.
10. Integrated activity of the midbrain, activity of the cerebellum. Structure, topography, neural connections.
11. Integrated activity of the cerebral cortex. Frontal, occipital, parietal regions, right and left hemispheres, the main differences in their processing of information.
12. Physiological properties of the autonomic nervous system. Her participation in emotional reactions. Sympathetic and parasympathetic divisions of the autonomic nervous system.
13. Reticular formation, its topography, influence on the activity of the brain, communication with other areas of the brain. Controlling role in the transfer of information.
14. Conducting nervous excitement in the body. The property of nerve fibers in conducting and transmitting information, the systemic organization of the pathways. Pathways of the brain and spinal cord.
15. Features and conditions that form synaptic transmission of information, stages and mechanisms of synaptic transmission. Features of synaptic connections of the brain, spinal cord, visceral system.
16. Fundamental principles the theory of reflex activity. Conditioned and unconditioned (innate) reflexes. The difference between conditioned and unconditioned reflexes.
17. Processing information in the central nervous system. The concept of "sensory system". The structure of connections that form sensory systems.
18. Transformation and transmission of signals to the sensor system. Receptor sensitivity. Encoding stimuli in the sensory system.
19. The structure of the visual analyzer, its physiological characteristics. Pathways of transmission of visual information to the centers of the brain.
20. Visual reflexes: accommodation, photoreception. Features of the structure of the retina. Characteristics of photoreceptors.
21. Central visual pathways. Visual cortex activity. Technology for the formation and transmission of visual information. Reaction of the cortex to visual drainage.
22. Anatomy and physiology of hearing organs. The auditory system. Central auditory tract. Characteristics of neurons that form sound perception.
23. Vestibular system (balance apparatus). Features of hair cells in the equilibrium apparatus. Conducting system and centers of equilibrium in the cortex.
24. General principles functioning of the body: correlation, regulation, self-regulation, reflex activity.
25. Functional systems. General systems theory. The concepts of "system genesis", "system quantization". Development of systems in phylogenesis.
26. Nervous regulation of the functions of internal organs. Hormonal regulation of physiological functions. Causes of hormonal regulation disorders.
27. Physiology of physical activity. Concepts, definitions. Features of motor activity in conditions of changes in irritating factors. The role of stimulating factors in the realization of activity, the phenomenon of efferentation.
28. "Motor cortex", its functions, topography. Classification of movements. Orientation and manipulation movements. Nervous pathways in the formation of motor reactions.
29. Mechanisms of initiation of motor acts. Emotional and cognitive brain, role in efferent reactions.
30. Thermoregulation of the body. Basic concepts. The body's response to external temperature. The influence of temperature effects on the human body. Regulators of temperature reactions.
31. Systemic mechanisms in the regulation of body temperature. Individual characteristics reactions to temperature conditions... Daily fluctuations in body temperature.
32. Localization, features, properties of thermostats. Heat generation and heat transfer in various conditions of the organism's stay. Neuroregulation of heat.
33. Fluids of the body. Functions of water in the human body. Biological functions of water. The main "water depots" in the body.
34. Methods for the determination of liquid media in the body. Electrolyte composition of liquid media. Sources of intake and routes of excretion of water and electrolytes.
35. Blood as the main liquid medium. Hematopoietic organs and processes of destruction of blood elements. Blood composition, basic depot. The "working" blood volume is normal.
36. Blood coagulation, mechanisms of hemostasis. Fibrinolysis (dissolution) of blood. Causes and consequences.
37. Transcellular (intercellular) fluids, composition, functions. The role of intercellular fluid in ensuring optimal turgor of the human body.
38. Osmotic pressure of tissues and organs (osmolality), tonicity of solutions. Causes of violation of osmotic pressure, consequences for the body.
39. Metabolism and energy in the body. Types of metabolism, stages, phenomena of anabolism and catabolism. Metabolic disorders and their consequences for the body.
40. Mineral metabolism in the body, ionic composition of liquids. Physiological role potassium, calcium, magnesium and other elements in mineral metabolism. The consequences of a violation of mineral metabolism.
41. Exchange of fats, their biological role, heat capacity, participation in metabolism. Energy value of fats. Body fat.
42. Metabolism of carbohydrates, the mechanism of assimilation, the role in the maintenance of vital activity, products of carbohydrate oxidation, energy value. The consequences of excess carbohydrate deposition.
44. Thermodynamics of living systems. Factors influencing the formation, accumulation and consumption of heat energy. The efficiency of a living cell. Heat limits in various tissues of the body.
45. Heat consumption in the body. Basal metabolism and energy expenditure. Influence of activities on energy consumption. Permissible limits of overheating and hypothermia of tissues and organs.
46. Functional asymmetry of the brain. Types of asymmetry by the nature of manifestation, functional asymmetries. The role of asymmetry in the formation of individual functions.
47. Morphological asymmetry of the cerebral hemispheres. Forms of joint activity of the hemispheres: integration of information, control functions, interhemispheric transfer of information.
48. Left-handedness and right-handedness in brain activity. The origin of left-handedness. Types of left-handedness. Age features of the formation of left-handedness.
49. Blocks of information processing in the central nervous system. Formation of blocks, their structures, actual nerve centers, their links "support" in information processing.
50. Receptors as the main "receivers" of information from the external and internal environments. Information transmission systems that receive receptors. Reception levels by function.
51. The concept of "analyzers". Their functions, specificity. Connections between analyzers. The principle of "divergence" and "convergence" in supporting the adoption of specific actions in response to stimulus.
52. Level centers of the cerebral cortex. Primary, secondary and tertiary zones of the cortex. Functional features of each of these zones.
53. The block of regulation of tone and wakefulness in the cortex as a modeling system of the brain. The performed functions of this block, communication with the reticular formation as a controlling system.
54. Block of programming, regulation and control of complex forms of activity. The functions of the motor analyzer, areas of the motor cortex. Neural network of motor analyzers.
55. Functional organization of the motor cortex. Motor pathways of the brain (pyramidal tract). Formation of motor programs for information transmission.
56. The structure of the spine. Departments, quantity and quality of vertebrae. The size of the cross-section of different parts of the vertebrae. "Laying" and protecting the spinal cord from damage.
57. Structures and functions of the spinal cord: topography, structure, size. Nerve nuclei of the spinal cord, nervous afferent and efferent pathways.
58. White and gray matter of the spinal cord. Functions of individual sections of the gray matter of the spinal cord. Spinal nerves, their functions, topography of nerve trunks, their "service areas".
59. The medulla oblongata. Internal structure, functions. Characteristics and functions of the nuclei and exiting nerves. The structure of the information they process.
60. Hindbrain. Structure (bridge, cerebellum). Outgoing nerves, nuclei, their role in the perception and processing of information, "controlling function".
61. Middle and diencephalon. The structure and function of the thalamus (visual hillock). Neurons of nuclei as centers of accumulation and processing of information.
62. Final brain. The cerebral cortex, lobes of the cortex, the right and left hemispheres, furrows. The role of the corpus callosum in the functional activity of the cerebral cortex.
LITERATURE
1. Anatomy. Physiology. Human psychology: a short illustrated dictionary / ed. acad. ... - SPb. : Peter, 2001 .-- 256 p.
2. Human anatomy. At 2 o'clock, Part 2 / ed. ... - M.: Medicine, 1993 .-- 549 p.
3. Anokhin, and the neurophysiology of the conditioned reflex /. - M.: Medicine, 1968. - 547p.
4. Danilova,: textbook. for universities /. - M.: Aspect-Press. 2002 .-- 373 p.
5. Pribram, K. Languages of the brain / K. Pribram. - M.: Progress, 1975 .-- 464 p.
6. Sokolov, and the conditioned reflex. A New Look/. - M.: Moscow Psychological and Social Institute. 2003 .-- 287s.
7. Physiology. Fundamentals and functional systems: a course of lectures / ed. ... - M.: "Science", 2000. - 784 p.
St. plan 2011, pos. 19
Educational edition
Parkhomenko Daria Alexandrovna
ANATOMY AND PHYSIOLOGY
CENTRAL NERVOUS SYSTEM
Toolkit
for students of specialty 1 - "Engineering and psychological support of information technologies"
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Gray and white matter of the brain. White matter of the hemispheres. Gray matter of the hemisphere. Frontal lobe. Parietal lobe. The temporal lobe. Occipital lobe. Island.
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ANATOMY OF THE CENTRAL NERVOUS SYSTEM
ESSAY
Topic: "Gray and white matter of the brain"
WHITE MATTER HEMISPHERE
The entire space between the gray matter of the cerebral cortex and the basal nuclei is occupied by white matter. The white matter of the hemispheres is formed by nerve fibers connecting the cortex of one gyrus with the cortex of the other convolutions of its own and opposite hemispheres, as well as with the underlying formations. Topographers in white matter distinguish four parts, not sharply delimited from each other:
white matter in convolutions between furrows;
the area of white matter in the outer parts of the hemisphere - the semi-oval center ( centrum semiovale);
radiant crown ( corona radiata) formed by radially diverging fibers entering the inner capsule ( capsula interna) and leaving it;
the central substance of the corpus callosum ( corpus callosum), inner capsule and long associative fibers.
Nerve fibers of the white matter are divided into associative, commissural and projection.
Associative fibers connect different parts of the cortex of the same hemisphere. They are divided into short and long. Short fibers connect adjacent gyri in the form of arcuate bundles. Long associative fibers connect parts of the cortex that are more distant from each other.
Commissural fibers, which are part of the cerebral commissures, or adhesions, connect not only symmetrical points, but also the cortex belonging to different parts of the opposite hemispheres.
Most of the commissural fibers are part of the corpus callosum, which connects parts of both hemispheres related neencephalon... Two brain spikes commissura anterior and commissura fornicis, much smaller in size related to the olfactory brain rhinencephalon and connect: commissura anterior- the olfactory lobes and both parahippocampal convolutions, commissura fornicis- hippocampus.
Projection fibers connect the cerebral cortex with the underlying formations, and through them with the periphery. These fibers are divided into:
centripetal - ascending, corticopetal, afferent. They conduct excitation towards the cortex;
centrifugal (descending, corticofugal, efferent).
The projection fibers in the white matter of the hemisphere, closer to the cortex, form a radiant crown, and then their main part converges into an inner capsule, which is a layer of white matter between the lenticular nucleus ( nucleus lentiformis) on the one hand, and the tailed kernel ( nucleus caudatus) and thalamus ( thalamus) - with another. On the frontal section of the brain, the inner capsule looks like a slanting white stripe continuing into the brain stem. In the inner capsule, the front leg is distinguished ( crus anterius), - between the caudate nucleus and the anterior half of the inner surface of the lenticular nucleus, the hind leg ( crus posterius), - between the thalamus and the posterior half of the lenticular nucleus and the knee ( genu), lying at the bend between both parts of the inner capsule. Projection fibers can be classified according to their length into the following three systems, starting with the longest:
Tractus corticospinalis (pyramidalis) conducts motor volitional impulses to the muscles of the trunk and limbs.
Tractus corticonuclearis- pathways to the motor nuclei of the cranial nerves. All motor fibers are collected in a small space in the inner capsule (knee and anterior two-thirds of its hind leg). And if they are damaged, unilateral paralysis of the opposite side of the body is observed in this place.
Tractus corticopontini- paths from the cerebral cortex to the nuclei of the bridge. Through these pathways, the cerebral cortex has an inhibitory and regulatory effect on the activity of the cerebellum.
Fibrae thalamocorticalis et corticothalamici- fibers from the thalamus to the cortex and back from the cortex to the thalamus.
GRAY HEMISPHERE SUBSTANCE
Hemisphere surface, cloak ( pallium), formed by a uniform layer of gray matter 1.3 - 4.5 mm thick, containing nerve cells... The surface of the cloak has a very complex pattern, consisting of alternating grooves and ridges between them in different directions, called convolutions, gyri... The size and shape of the furrows are subject to significant individual fluctuations, as a result of which not only the brains of different people, but even the hemispheres of the same individual are not quite similar in the pattern of the furrows.
Deep permanent furrows are used to divide each hemisphere into large areas, called shares, lobi; the latter, in turn, are divided into lobules and convolutions. Allocate five lobes of the hemisphere: frontal ( lobus frontalis), parietal ( lobus parietalis), temporal ( lobus temporalis), occipital ( lobus occipitalis) and a lobule hidden at the bottom of the lateral groove, the so-called islet ( insula).
The upper-lateral surface of the hemisphere is delimited into lobes by means of three grooves: the lateral, central and upper end of the parieto-occipital groove. Lateral groove ( sulcus cerebri lateralis) begins on the basal surface of the hemisphere from the lateral fossa and then passes to the upper lateral surface. Central furrow ( sulcus cenrtalis) starts at the top edge of the hemisphere and goes forward and downward. The area of the hemisphere in front of the central sulcus belongs to the frontal lobe. The part of the cerebral surface lying behind the central sulcus is the parietal lobe. The posterior border of the parietal lobe is the end of the parieto-occipital sulcus ( sulcus parietooccipitalis), located on the medial surface of the hemisphere.
Each lobe consists of a series of convolutions, called lobules in some places, which are limited by the grooves of the cerebral surface.
Frontal lobe
In the posterior part of the outer surface of this lobe passes sulcus precentralis almost parallel to direction sulcus centralis... Two grooves extend from it in the longitudinal direction: sulcus frontalis superior et sulcus frontalis inferior... Due to this, the frontal lobe is divided into four convolutions. Vertical gyrus, gyrus precentralis, is located between the central and precentral grooves. The horizontal convolutions of the frontal lobe are: superior frontal ( gyrus frontalis superior), middle frontal ( gyrus frontalis medius) and lower frontal ( gyrus frontalis inferior) share.
Parietal lobe
On it, approximately parallel to the central groove is located sulcus postcentralis usually merging with sulcus intraparietalis that goes horizontally. Depending on the location of these furrows, the parietal lobe is divided into three convolutions. Vertical gyrus, gyrus postcentralis, goes behind the central sulcus in the same direction as the precentral gyrus. The superior parietal gyrus, or lobule ( lobulus parietalis superior), below - lobulus parietalis inferior.
Temporal lobe
The lateral surface of this lobe has three longitudinal convolutions, delimited from each other sulcus temporalis superio r and sulcus temporalis inferior... Between the superior and inferior temporal grooves stretches gyrus temporalis medius... Below it passes gyrus temporalis inferior.
Occipital lobe
The grooves of the lateral surface of this lobe are changeable and unstable. Of these, a running transverse is distinguished sulcus occipitalis transversus, usually connecting to the end of the inter-parietal sulcus.
Island
This lobule is in the shape of a triangle. The surface of the islet is covered with short convolutions.
The lower surface of the hemisphere in that part of it that lies anterior to the lateral fossa belongs to the frontal lobe.
Here parallel to the medial edge of the hemisphere passes sulcus olfactorius... On the posterior part of the basal surface of the hemisphere, two grooves are visible: sulcus occipitotemporalis running in the direction from the occipital pole to the temporal and limiting gyrus occipitotemporalis lateralis, and running parallel to it sulcus collateralis... Between them is gyrus occipitotemporalis medialis... Two convolutions are located medially from the collateral groove: between the posterior part of this groove and sulcus calcarinus lies gyrus lingualis; between the anterior part of this furrow and the deep sulcus hippocampi lies gyrus parahippocampalis... This gyrus, adjacent to the brain stem, is already on the medial surface of the hemisphere.
On the medial surface of the hemisphere there is a groove of the corpus callosum ( sulcus corpori callosi), which runs directly above the corpus callosum and continues with its posterior end into a deep sulcus hippocampi, which is directed forward and downward. Parallel and above this groove passes along the medial surface of the hemisphere sulcus cinguli... Paracentral lobule ( lobulus paracentralis) is called a small area above the lingual groove. Behind the paracentral lobule there is a quadrangular surface (the so-called pre-wedge, precuneus). It belongs to the parietal lobe. Behind the pre-wedge lies a separate section of the cortex related to the occipital lobe - a wedge ( cuneus). Between the reed groove and the groove of the corpus callosum, the cingulate gyrus ( gyrus cinguli), which through the isthmus ( isthmus) continues into the parahippocampal gyrus, ending with a hook ( uncus). Gyrus cinguli, isthmus and gyrus parahippocampali s together form a vaulted gyrus ( gyrus fornicatus), which describes an almost complete circle, open only from below and in front. The vaulted gyrus is not related to any of the lobes of the cloak. It belongs to the limbic region. Limbic region - part new bark cerebral hemispheres, occupying the cingulate and parahippocampal gyrus; is part of the limbic system. Pushing the edge sulcus hippocampi, you can see a narrow jagged gray strip, which is a rudimentary gyrus gyrus dentatus.
L I T E R A T U R A
Great medical encyclopedia. vol. 6, M., 1977
2. Great medical encyclopedia. t. 11, M., 1979
3. M.G. Weight gain, N.K. Lysenkov, V.I. Bushkovich. Human anatomy. M., 1985
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It consists of the thalamus, epithalamus, metathalamus and hypothalamus. ascending fibers from the hypothalamus from the nuclei of the suture of the blue spot of the reticular formation of the brainstem and partly from the dorsal thalamic tract as part of the medial loop. Hypothalamus General structure and location of the hypothalamus.
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Introduction
Thalamus (optic tubercle)
Hypothalamus
Conclusion
Bibliography
Introduction
For the modern psychologist, the anatomy of the central nervous system is the basic layer of psychological knowledge. Without an understanding of the physiological work of the brain, it is impossible to qualitatively study mental processes and phenomena, as well as understand their essence.
Speaking about the thalamus and hypothalamus, one should first talk aboutdiencephalon(diencephalon ). The diencephalon is located above the midbrain, under the corpus callosum. It consists of the thalamus, epithalamus, metathalamus, and hypothalamus. At the base of the brain, its border in front runs along the front surface of the optic nerve intersection, the front edge of the posterior perforated substance and the optic tracts, and behind - along the edge of the brain legs. On the dorsal surface, the anterior border is the terminal strip that separates the diencephalon from the telencephalon, and the posterior border is the groove that separates the diencephalon from the superior hillocks of the midbrain. On a sagittal section, the diencephalon is visible under the corpus callosum and fornix.
The cavity of the diencephalon is III the ventricle, which, through the right and left interventricular openings, communicates with the lateral ventricles located inside the cerebral hemispheres and through the aqueduct of the brain - with the cavity IV ventricle of the brain. In the upper wall III the ventricle is the choroid plexus, which, along with the plexuses in the other ventricles of the brain, is involved in the formation of cerebrospinal fluid.
The thalamic brain is subdivided into paired formations:
thalamus ( visual hillock);
metathalamus (zathalamic area);
epithalamus (suprathalamic region);
subthalamus (subthalamic region).
The metathalamus (zathalamic region) is formed by pairedmedial and lateral geniculate bodieslocated behind each thalamus. In the geniculate bodies, nuclei are located, in which impulses are switched to the cortical parts of the visual and auditory analyzer.
The medial geniculate body is located behind the thalamic cushion; together with the lower hillocks of the midbrain roof plate, it is the subcortical center of the auditory analyzer.
The lateral geniculate body is located downward from the thalamic cushion. Together with the upper tubercles of the quadruple, it forms the subcortical center of the visual analyzer.
The epithalamus (supra-thalamic region) includespineal gland (pineal gland), leads and lead triangles... In the triangles of the leashes lie the nuclei related to the olfactory analyzer. The leashes extend from the leash triangles, run caudally, join by adhesion, and merge into the pineal gland. The latter, as it were, is suspended from them and is located between the upper tubercles of the quadruple. The pineal gland is an endocrine gland. Its functions are not fully established, but it is assumed that it regulates the onset of puberty.
Thalamus (optic tubercle)
General structure and location of the thalamus.
Thalamus, or optic hillock, is a paired ovoid formation with a volume of about 3.3 cm 3 consisting mainly of gray matter (clusters of numerous nuclei). Thalamus are formed due to thickening of the lateral walls of the diencephalon. In front, the sharpened part of the thalamus formsanterior tuberclein which the intermediate centers of the sensory (afferent) pathways are located, going from the brain stem to the cerebral cortex. The posterior, widened and rounded part of the thalamus - pillow - contains a subcortical visual center.
Picture 1 ... The diencephalon in a sagittal section.
The thickness of the gray matter of the thalamus is divided by a vertical Y -shaped layer (plate) of white matter into three parts - anterior, medial and lateral.
Medial surface of the thalamusclearly visible on the sagittal (sagittal - sagittal (lat. " sagitta " - arrow), dividing into symmetrical right and left halves) section of the brain (Fig. 1). The medial (i.e., located closer to the middle) surface of the right and left thalamus, facing each other, form the lateral walls III cerebral ventricle (diencephalon cavity) in the middle, they are interconnectedinterthalamic fusion.
The anterior (inferior) surface of the thalamusfused with the hypothalamus, through it from the caudal side (i.e., located closer to the lower part of the body), the pathways from the legs of the brain enter the diencephalon.
Lateral (i.e. lateral) surface thalamus is bordered byinner capsule -a layer of white matter of the cerebral hemispheres, consisting of projection fibers connecting the cerebral cortex with the underlying cerebral structures.
There are several groups in each of these parts of the thalamus.thalamic nuclei... In total, the thalamus contains from 40 to 150 specialized nuclei.
The functional significance of the thalamic nuclei.
According to the topography, the thalamic nuclei are combined into 8 main groups:
1. front group;
2. mediodorsal group;
3. a group of midline nuclei;
4. dorsolateral group;
5. ventrolateral group;
6. ventral posterior medial group;
7. posterior group (nuclei of the thalamus pillow);
8. Intralaminar group.
Thalamus nuclei are divided into sensory ( specific and non-specific),motor and associative... Let us consider the main groups of thalamic nuclei necessary for understanding its functional role in the transmission of sensory information to the cerebral cortex.
In front of the thalamus is located front group thalamic nuclei (fig. 2). The largest of them areanteroventral core and anteromedialcore. They receive afferent fibers from the mastoid bodies, the olfactory center of the diencephalon. Efferent fibers (descending, i.e., emitting impulses from the brain) from the anterior nuclei are directed to the cingulate gyrus of the cerebral cortex.
The anterior group of thalamic nuclei and associated structures is an important component of the limbic system of the brain, which controls psychoemotional behavior.
Rice. 2 ... Thalamic nuclei topography
In the medial part of the thalamus, there aremediodorsal core and a group of midline nuclei.
Mediodorsal nucleushas bilateral connections with the olfactory cortex of the frontal lobe and the cingulate gyrus of the cerebral hemispheres, the amygdala and the anteromedial nucleus of the thalamus. Functionally, it is also closely associated with the limbic system and has two-way connections with the cortex of the parietal, temporal and insular lobes of the brain.
The mediodorsal nucleus is involved in the implementation of higher mental processes. Its destruction leads to a decrease in anxiety, anxiety, tension, aggressiveness, and the elimination of obsessive thoughts.
Midline nucleiare numerous and occupy the most medial position in the thalamus. They receive afferent (i.e., ascending) fibers from the hypothalamus, from the nuclei of the suture, the blue spot of the reticular formation of the brainstem, and partly from the spinal thalamic tract in the medial loop. Efferent fibers from the midline nuclei are directed to the hippocampus, amygdala and cingulate gyrus of the cerebral hemispheres, which are part of the limbic system. Connections with the cerebral cortex are bilateral.
The nuclei of the midline play an important role in the processes of awakening and activation of the cerebral cortex, as well as in providing memory processes.
In the lateral (i.e. lateral) part of the thalamus are locateddorsolateral, ventrolateral, ventral posteromedial and posterior group of nuclei.
Dorsolateral group nucleirelatively little studied. They are known to be involved in the pain perception system.
Ventrolateral group nucleianatomically and functionally differ from each other.Posterior nuclei of the ventrolateral groupoften viewed as a single ventrolateral thalamic nucleus. This group receives fibers of the ascending path of general sensitivity as part of the medial loop. Fibers of gustatory sensitivity and fibers from the vestibular nuclei also come here. Efferent fibers, starting from the nuclei of the ventrolateral group, are sent to the cortex of the parietal lobe of the cerebral hemispheres, where they conduct somatosensory information from the whole body.
TO backgroup nuclei(nucleus of the thalamic cushion) afferent fibers from the upper hillocks of the quadruple and fibers in the optic tract. Efferent fibers are widely distributed in the cortex of the frontal, parietal, occipital, temporal and limbic lobes of the cerebral hemispheres.
The nuclear centers of the thalamus cushion are implicated in comprehensive analysis various sensory stimuli. They play a significant role in the perceptual (associated with perception) and cognitive (cognitive, mental) activity of the brain, as well as in the processes of memory - storage and reproduction of information.
Intralaminar group of nucleithalamus lies in the thickness of the vertical Y -shaped layer of white matter. Intralaminar nuclei are interconnected with the basal nuclei, the dentate nucleus of the cerebellum and the cerebral cortex.
These nuclei play an important role in the brain's activation system. Damage to the intralaminar nuclei in both thalamuses leads to a sharp decrease in motor activity, as well as apathy and destruction of the motivational structure of the personality.
The cerebral cortex, due to bilateral connections with the thalamic nuclei, is able to exert a regulatory effect on their functional activity.
Thus, the main functions of the thalamus are:
processing of sensory information from receptors and subcortical switching centers with its subsequent transfer to the cortex;
participation in the regulation of movements;
ensuring communication and integration of various parts of the brain.
Hypothalamus
General structure and location of the hypothalamus.
Hypothalamus (hypothalamus ) is the ventral (i.e., abdominal) diencephalon. It includes a complex of formations located under III ventricle. The hypothalamus is anteriorly limitedvisual crossover (chiasma), laterally - by the anterior part of the subthalamus, the inner capsule and the optic tracts extending from the chiasm. Behind, the hypothalamus continues into the lining of the midbrain. The hypothalamus includesmastoid bodies, gray tubercle and optic chiasm. Mastoid bodieslocated on the sides of the midline in front of the posterior perforated substance. These are formations of an irregular spherical shape. white... In front of the gray bump is locatedoptic chiasm... In it, there is a transition to the opposite side of the part of the optic nerve fibers coming from the medial half of the retina. After the intersection, the visual tracts are formed.
Gray bump located anterior to the mastoid bodies, between the optic tracts. The gray bump is a hollow protrusion of the bottom wall III ventricle formed by a thin plate of gray matter. The top of the gray tubercle is elongated into a narrow hollow funnel at the end of which there is pituitary gland [4; eighteen].
Pituitary gland: structure and function
Pituitary (hypophysis) - endocrine gland, it is located in a special depression of the base of the skull, "Turkish saddle" and with the help of a leg is connected to the base of the brain. In the pituitary gland, the anterior lobe (adenohypophysis - glandular pituitary gland) and the posterior lobe (neurohypophysis).
The posterior lobe, or neurohypophysis, consists of neuroglial cells and is a continuation of the hypothalamic funnel. Larger share - adenohypophysis, built of glandular cells. Due to the close interaction of the hypothalamus with the pituitary gland in the diencephalon, a singlehypital-pituitary system,managing the work of all endocrine glands, and with their help - the autonomic functions of the body (Fig. 3).
Figure 3. The pituitary gland and its effect on other endocrine glands
In the gray matter of the hypothalamus, 32 pairs of nuclei are secreted. Interaction with the pituitary gland is carried out through neurohormones secreted by the nuclei of the hypothalamus -releasing hormones... Through the system of blood vessels, they enter the anterior lobe of the pituitary gland (adenohypophysis), where they promote the release of tropic hormones that stimulate the synthesis of specific hormones in other endocrine glands.
In the anterior lobe of the pituitary gland tropic hormones (thyroid-stimulating hormone - thyrotropin, adrenocorticotropic hormone - corticotropin and gonadotropic hormones - gonadotropins) and effector hormones (growth hormones - somatotropin and prolactin).
Hormones of the anterior pituitary gland
Tropic:
Thyroid stimulating hormone (thyrotropin)stimulates the function of the thyroid gland. If the pituitary gland is removed or destroyed in animals, then the atrophy of the thyroid gland occurs, and the administration of thyrotropin restores its functions.
Adrenocorticotropic hormone (corticotropin)stimulates the function of the bundle zone of the adrenal cortex, in which hormones are formedglucocorticoids.The effect of the hormone on the glomerular and reticular zones is less pronounced. Removal of the pituitary gland in animals leads to atrophy of the adrenal cortex. Atrophic processes cover all areas of the adrenal cortex, but the most profound changes occur in the cells of the reticular and fascicular areas. The extra-adrenal effect of corticotropin is expressed in the stimulation of lipolysis processes, increased pigmentation, and anabolic effects.
Gonadotropic hormones (gonadotropins).Follicle-stimulating hormone ( follitropin) stimulates the growth of the vesicular follicle in the ovary. The effect of follitropin on the formation of female sex hormones (estrogens) is small. This hormone is found in both women and men. In men, under the influence of follitropin, the formation of germ cells (sperm) occurs. Luteinizing hormone ( lutropin) is necessary for the growth of the vesicular ovarian follicle in the stages preceding ovulation, and for ovulation itself (rupture of the membrane of the mature follicle and the release of an egg from it), the formation of a corpus luteum at the site of the burst follicle. Lutropin stimulates the formation of female sex hormones - estrogen. However, in order for this hormone to exert its effect on the ovary, a preliminary long-term action of follitropin is necessary. Lutropin stimulates production progesterone corpus luteum. Lutropin is available in both women and men. In men, it promotes the formation of male sex hormones - androgens.
Effective:
Growth hormone (somatotropin)stimulates the growth of the body by enhancing the formation of protein. Under the influence of the growth of epiphyseal cartilage in the long bones of the upper and lower extremities, the bones grow in length. Growth hormone enhances insulin secretion through somatomedinov, formed in the liver.
Prolactin stimulates the formation of milk in the alveoli of the mammary glands. Prolactin exerts its effect on the mammary glands after the preliminary action of the female sex hormones progesterone and estrogens on them. The act of sucking stimulates the formation and release of prolactin. Prolactin also has a luteotropic effect (contributes to the long-term functioning of the corpus luteum and the formation of the hormone progesterone by it).
Processes in the posterior lobe of the pituitary gland
In the posterior lobe of the pituitary gland, hormones are not produced. Inactive hormones come here, which are synthesized in the paraventricular and supraoptic nuclei of the hypothalamus.
In the neurons of the paraventricular nucleus, a hormone is predominantly formed oxytocin, and in the neurons of the supraoptic nucleus -vasopressin (antidiuretic hormone).These hormones accumulate in the cells of the posterior pituitary gland, where they are converted into active hormones.
Vasopressin (antidiuretic hormone)plays an important role in the processes of urination and, to a lesser extent, in the regulation of the tone of the blood vessels. Vasopressin, or antidiuretic hormone - ADH (diuresis - urine excretion) - stimulates the reabsorption (resorption) of water in the renal tubules.
Oxytocin (Ocitonin)enhances the contraction of the uterus. Its reduction increases sharply if it was previously under the influence of the female sex hormones estrogen. During pregnancy, oxytocin does not affect the uterus, since under the influence of the corpus luteum hormone progesterone, it becomes insensitive to oxytocin. Mechanical irritation of the cervix causes reflex oxytocin release. Oxytocin also has the ability to stimulate milk production. The act of sucking reflexively promotes the release of oxytocin from the neurohypophysis and the release of milk. In a state of tension, the pituitary gland secretes an additional amount of ACTH, which stimulates the release of adaptive hormones by the adrenal cortex.
The functional significance of the nuclei of the hypothalamus
V antero-lateral part the hypothalamus is distinguished front and middlegroups of hypothalamic nuclei (Fig. 4).
Figure 4. Topography of the nuclei of the hypothalamus
The front group includes suprachiasmatic nuclei, preoptic nucleus,and the largest -supraoptic and paraventricular kernels.
In the nuclei of the anterior group are localized:
center of the parasympathetic division (PSNS) of the autonomic nervous system.
Stimulation of the anterior part of the hypothalamus leads to reactions of the parasympathetic type: a narrowing of the pupil, a decrease in the frequency of heart contractions, an expansion of the lumen of blood vessels, a drop in blood pressure, increased peristalsis (i.e., a wave-like contraction of the walls of hollow tubular organs, which promotes the movement of their contents to the outlets of the intestine);
heat transfer center. The destruction of the anterior section is accompanied by an irreversible increase in body temperature;
the center of thirst;
neurosecretory cells that produce vasopressin (supraoptic nucleus) and oxytocin ( paraventricular nucleus). In neurons paraventricular and supraopticnuclei, a neurosecret is formed, which moves along their axons to the posterior part of the pituitary gland (neurohypophysis), where it is released in the form of neurohormones -vasopressin and oxytocinentering the blood.
Damage to the anterior nuclei of the hypothalamus leads to the cessation of the release of vasopressin, as a result of whichdiabetes insipidus... Oxytocin has a stimulating effect on the smooth muscles of internal organs, such as the uterus. In general, the body's water-salt balance depends on these hormones.
In preoptic the nucleus produces one of the releasing hormones - luliberin, which stimulates the production of luteinizing hormone in the adenohypophysis, which controls the activity of the gonads.
Suprachiasmaticthe nuclei take an active part in the regulation of cyclic changes in the body's activity - circadian, or diurnal, biorhythms (for example, in the alternation of sleep and wakefulness).
To the middle group hypothalamic nuclei includedorsomedial and ventromedial nucleus, nucleus of the gray tubercle and the core of the funnel.
In the nuclei of the middle group are localized:
the center of hunger and satiety. Destructionventromedialthe hypothalamic nucleus leads to excess food intake (hyperphagia) and obesity, and damagekernels of a gray hillock- to a decrease in appetite and a sharp emaciation (cachexia);
sexual behavior center;
center of aggression;
the center of pleasure, which plays an important role in the formation of motivations and psychoemotional forms of behavior;
neurosecretory cells that produce releasing hormones (liberins and statins) that regulate the production of pituitary hormones: somatostatin, somatoliberin, luliberin, follyberin, prolactoliberin, thyreoliberin, etc. Through the hypothalamic-pituitary system, they affect the growth rate physical development and puberty, the formation of secondary sexual characteristics, the function of the reproductive system, as well as metabolism.
Middle group nuclei controls water, fat and carbohydrate metabolism, affects the level of sugar in the blood, the ionic balance of the body, the permeability of blood vessels and cell membranes.
The back of the hypothalamus located between the gray tubercle and the posterior perforated substance and consists of the right and leftmastoid bodies.
In the back of the hypothalamus, the largest nuclei are: medial and lateral nucleus, posterior hypothalamic nucleus.
In the nuclei of the posterior group are localized:
center coordinating the activity of the sympathetic division (SNS) of the autonomic nervous system (posterior hypothalamic nucleus). Stimulation of this nucleus leads to sympathetic reactions: pupil dilation, increased heart rate and blood pressure, increased respiration and decreased tonic contractions of the intestine;
heat production center (posterior hypothalamic nucleus). Destruction of the posterior hypothalamus causes lethargy, drowsiness and a decrease in body temperature;
subcortical centers of the olfactory analyzer. Medial and lateral nucleusin each mastoid body, they are the subcortical centers of the olfactory analyzer, and are also part of the limbic system;
neurosecretory cells that produce releasing hormones that regulate the production of pituitary hormones.
Features of the blood supply to the hypothalamus
The nuclei of the hypothalamus receive an abundant blood supply. The capillary network of the hypothalamus is several times larger in branching than in other parts of the central nervous system. One of the features of the capillaries of the hypothalamus is their high permeability, due to the thinning of the walls of the capillaries and their fenestration ("fenestration" - the presence of gaps - "windows" - between adjacent endothelial cells of capillaries (from Lat. " fenestra As a result, the blood-brain barrier (BBB) is poorly expressed in the hypothalamus, and the hypothalamic neurons are able to perceive changes in the composition of cerebrospinal fluid and blood (temperature, ion content, the presence and amount of hormones, etc.).
The functional significance of the hypothalamus
The hypothalamus is the central link connecting the nervous and humoral mechanisms of regulation of the autonomic functions of the body. The control function of the hypothalamus is due to the ability of its cells to secrete and axonal transport of regulatory substances, which are transferred to other brain structures, cerebrospinal fluid, blood or pituitary gland, changing the functional activity of target organs.
There are 4 neuroendocrine systems in the hypothalamus:
Hypothalamic-extrahypothalamic systemrepresented by neurosecretory cells of the hypothalamus, whose axons go to the thalamus, the structures of the limbic system, the medulla oblongata. These cells secrete endogenous opioids, somatostatin, etc.
Hypothalamic-adenohypophyseal systemconnects the nuclei of the posterior hypothalamus with the anterior pituitary gland. Releasing hormones (liberins and statins) are transported along this pathway. By means of them, the hypothalamus regulates the secretion of tropic hormones of the adenohypophysis, which determine the secretory activity of the endocrine glands (thyroid, genital, etc.).
Hypothalamic-metagipophyseal systemconnects neurosecretory cells of the hypothalamus with the pituitary gland. Melanostatin and melanoliberin are transported along the axons of these cells, which regulate the synthesis of melanin, a pigment that determines the color of the skin, hair, iris and other tissues of the body.
Hypothalamic-neurohypophyseal systemconnects the nuclei of the anterior hypothalamus with the posterior (glandular) lobe of the pituitary gland. These axons carry vasopressin and oxytocin, which accumulate in the posterior lobe of the pituitary gland and are released into the bloodstream as needed.
Conclusion
Thus, the dorsal diencephalon is a phylogenetically youngerthalamic brain,which is the highest subcortical sensory center, in which almost all afferent pathways are switched, carrying sensory information from the organs of the body and sensory organs to the cerebral hemispheres. The tasks of the hypothalamus also include the management of psychoemotional behavior and participation in the implementation of higher mental and psychological processes, in particular memory.
Ventral section - hypothalamus is phylogenetically older education. The hypothalamic-pituitary system controls the humoral regulation of water-salt balance, metabolism and energy, work immune system, thermoregulation, reproductive function, etc. Fulfilling a regulatory role in this system, the hypothalamus is the highest center that controls the autonomic (autonomic) nervous system.
Bibliography
- Human Anatomy / Ed. M.R. Sapina. - M .: Medicine, 1993.
- Bloom F., Leiserson A., Hofstedter L. Brain, Mind Behavior. - M .: Mir, 1988.
- Histology / Ed. V.G. Eliseeva. - M .: Medicine, 1983.
- Prives M.G., Lysenkov N.K., Bushkovich V.I. Human anatomy. - M .: Medicine, 1985.
- Sinelnikov R.D., Sinelnikov Ya.R. Atlas of human anatomy. - M .: Medicine, 1994.
- Tishevskaya I.A. Anatomy of the Central Nervous System: A Study Guide. - Chelyabinsk: SUSU Publishing House, 2000.
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Nerve endings are located throughout the human body. They carry the most important function and are an integral part of the entire system. The structure of the human nervous system is a complex branched structure that runs through the entire body.
The physiology of the nervous system is a complex composite structure.
The neuron is considered the basic structural and functional unit of the nervous system. Its processes form fibers that are excited upon exposure and transmit impulse. The impulses reach the centers where they are analyzed. After analyzing the received signal, the brain transmits the necessary response to the stimulus to the corresponding organs or parts of the body. The human nervous system is briefly described by the following functions:
- providing reflexes;
- regulation of internal organs;
- ensuring the interaction of the body with the external environment, by adapting the body to changing external conditions and stimuli;
- interaction of all organs.
The importance of the nervous system is to ensure the vital activity of all parts of the body, as well as the interaction of a person with the outside world. The structure and functions of the nervous system are studied by neurology.
CNS structure
The anatomy of the central nervous system (CNS) is a collection of neuronal cells and neural processes in the spinal cord and brain. A neuron is a unit of the nervous system.
The function of the central nervous system is to provide reflex activity and the processing of impulses from the PNS.
The anatomy of the central nervous system, the main node of which is the brain, is a complex structure of branched fibers.
The higher nerve centers are concentrated in the cerebral hemispheres. This is the consciousness of a person, his personality, his intellectual abilities and speech. The main function of the cerebellum is to provide coordination of movements. The brain stem is inextricably linked with the hemispheres and cerebellum. In this section, there are the main nodes of the motor and sensory pathways, due to which such vital functions of the body as the regulation of blood circulation and the provision of respiration are provided. The spinal cord is the distribution structure of the central nervous system; it provides the branching of the fibers that form the PNS.
The spinal ganglion (ganglion) is a place where sensitive cells are concentrated. With the help of the spinal ganglion, the activity of the autonomic part of the peripheral nervous system is carried out. Ganglia or nerve nodes in the human nervous system are referred to as PNS, they function as analyzers. The ganglia are not part of the human central nervous system.
Structural features of PNS
Thanks to PNS, the activity of the whole human body is regulated. The PNS consists of cranial and spinal neurons and fibers that form the ganglia.
The structure and functions of the human peripheral nervous system are very complex, therefore, any slightest damage, for example, damage to blood vessels in the legs, can cause serious disruption of its work. Thanks to the PNS, all parts of the body are monitored and the vital activity of all organs is ensured. The importance of this nervous system for the body cannot be overestimated.
The PNS is divided into two divisions - the somatic and vegetative systems of the PNS.
The somatic nervous system performs double work- collection of information from the sense organs, and further transmission of this data to the central nervous system, as well as ensuring the motor activity of the body, by transmitting impulses from the central nervous system to the muscles. Thus, it is the somatic nervous system that is the instrument of human interaction with the outside world, since it processes signals received from the organs of vision, hearing and taste buds.
The autonomic nervous system provides the functions of all organs. It controls the heartbeat, blood supply, and respiratory activity. It contains only motor nerves that regulate muscle contraction.
To ensure the heartbeat and blood supply, the efforts of the person himself are not required - it is the vegetative part of the PNS that controls this. The principles of structure and function of the PNS are studied in neurology.
PNS departments
The PNS also consists of the afferent nervous system and the efferent division.
The afferent region is a collection of sensory fibers that process information from receptors and transmit it to the brain. The work of this department begins when the receptor is irritated due to some kind of influence.
The efferent system differs in that it processes impulses transmitted from the brain to the effectors, that is, the muscles and glands.
One of the important parts of the vegetative part of the PNS is the enteric nervous system. The enteric nervous system is formed from fibers located in the gastrointestinal tract and urinary tract. The enteric nervous system provides motility to the small and large intestine. This department also regulates the secretion secreted in the gastrointestinal tract, and provides a local blood supply.
The importance of the nervous system lies in ensuring the work of internal organs, intellectual function, motor skills, sensitivity and reflex activity. The central nervous system of a child develops not only during the prenatal period, but also during the first year of life. Ontogenesis of the nervous system begins from the first week after conception.
The basis for the development of the brain is formed as early as the third week after conception. The main functional nodes are indicated by the third month of pregnancy. By this time, the hemispheres, trunk and spinal cord have already been formed. By the sixth month, the higher regions of the brain are already better developed than the spinal region.
By the time the baby is born, the brain is the most developed. The size of the brain in a newborn is about one-eighth of the weight of a child and fluctuates around 400 g.
The activity of the central nervous system and PNS is greatly reduced in the first few days after birth. This may consist in the abundance of new irritating factors for the baby. This is how the plasticity of the nervous system manifests itself, that is, the ability of this structure to rebuild. As a rule, the increase in excitability occurs gradually, starting from the first seven days of life. The plasticity of the nervous system deteriorates with age.
CNS types
In the centers located in the cerebral cortex, two processes interact simultaneously - inhibition and excitation. The rate at which these states change determines the types of the nervous system. While one area of the central nervous system is excited, the other slows down. This determines the features of intellectual activity, such as attention, memory, concentration.
The types of the nervous system describe the differences between the speed of the processes of inhibition and excitation of the central nervous system in different people.
People can differ in character and temperament, depending on the characteristics of the processes in the central nervous system. Its features include the speed of switching neurons from the inhibition process to the excitation process, and vice versa.
The types of the nervous system are divided into four types.
- The weak type, or melancholic, is considered the most susceptible to the onset of neurological and psychoemotional disorders. It is characterized by slow processes of excitation and inhibition. The strong and unbalanced type is choleric. This type is distinguished by the predominance of excitation processes over inhibition processes.
- Strong and agile is a type of sanguine person. All processes occurring in the cerebral cortex are strong and active. A strong, but inert, or phlegmatic type, is characterized by a low speed of switching of nervous processes.
The types of the nervous system are interconnected with temperaments, but these concepts should be distinguished, because temperament characterizes a set of psychoemotional qualities, and the type of the central nervous system describes the physiological characteristics of the processes occurring in the central nervous system.
CNS protection
The anatomy of the nervous system is very complex. The CNS and PNS are affected by stress, overexertion, and nutritional deficiencies. For the normal functioning of the central nervous system, vitamins, amino acids and minerals are needed. Amino acids are involved in the work of the brain and are building material for neurons. Having figured out why and for what vitamins and amino acids are needed, it becomes clear how important it is to provide the body with the necessary amount of these substances. Glutamic acid, glycine and tyrosine are especially important for humans. The scheme of taking vitamin-mineral complexes for the prevention of diseases of the central nervous system and PNS is selected individually by the attending physician.
Damage to bundles of nerve fibers, congenital pathologies and abnormalities of the brain, as well as the action of infections and viruses - all this leads to disruption of the central nervous system and PNS and the development of various pathological conditions. Such pathologies can cause a number of very dangerous diseases - immobilization, paresis, muscle atrophy, encephalitis, and much more.
Malignant neoplasms in the brain or spinal cord lead to a number of neurological disorders. If there is a suspicion of an oncological disease of the central nervous system, an analysis is prescribed - the histology of the affected sections, that is, an examination of the composition of the tissue. A neuron as part of a cell can also mutate. Such mutations can be detected by histology. Histological analysis is carried out according to the testimony of a doctor and consists in the collection of the affected tissue and its further study. For benign lesions, histology is also performed.
There are many nerve endings in the human body, damage to which can cause a number of problems. Damage often results in impaired mobility of a part of the body. For example, an injury to the hand can lead to pain and impaired movement of the fingers. Osteochondrosis of the spine provoke pain in the foot due to the fact that an irritated or transmitted nerve sends pain impulses to receptors. If the foot hurts, people often look for the cause in a long walk or injury, but the pain syndrome can be triggered by an injury in the spine.
If there is a suspicion of damage to the PNS, as well as in case of any accompanying problems, it is necessary to undergo an examination by a specialist.