They make up 90% of all neurons. The processes do not leave the central nervous system, but provide numerous connections horizontally and vertically.
Feature: can generate action potentials with a frequency of 1000 per second. The reason is the short phase of trace hyperpolarization.
Interneurons carry out information processing; carry out communication between efferent and afferent neurons. They are divided into excitatory and inhibitory.
Efferent neurons.
These are neurons that transmit information from the nerve center to the executive organs.
Pyramidal cells of the motor cortex cerebral hemispheres, sending impulses to the motor neurons of the anterior horns spinal cord.
Motor neurons - axons extend beyond the CNS and end with synapses on effector structures.
The terminal part of the axon branches, but there are also branches at the beginning of the axon - axon collaterals. The junction of the motor neuron body and the axon is the axon hillock, which is the most excitable area. Here the AP is generated and then propagates along the axon.
On the neuron body huge amount synapses. If a synapse is formed by the axon of an excitatory interneuron, then when a transmitter acts on the postsynaptic membrane, depolarization or EPSP (excitatory postsynaptic potential) occurs. If the synapse is formed by the axon of the inhibitory cell, then when the mediator acts on the postsynaptic membrane, hyperpolarization or IPSP occurs. Algebraic sum EPSP and IPSP on the nerve cell body manifests itself in the occurrence of APs in the axon hillock.
The rhythmic activity of motor neurons under normal conditions is 10 impulses per second, but can increase several times.
Carrying out stimulation.
AP propagates due to local ion currents arising between the excited and unexcited sections of the membrane. Since AP is generated without energy expenditure, the nerve has the lowest fatigue.
Neuron Unions.
There are different terms for associations of neurons.
Nerve center– a complex of neurons in one or different places of the central nervous system (for example, the respiratory center).
Neural circuits are sequentially connected neurons that perform a specific task (from this point of view, a reflex arc is also a neural circuit).
Neural networks are a broader concept, because In addition to serial circuits, there are parallel circuits of neurons, as well as connections between them. Neural networks are structures that perform complex tasks (for example, information processing tasks).
NERVOUS REGULATION
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A connecting neuron that lies between sensory (afferent) and motor (efferent) neurons. Located in the central nervous system. Also called an interneuron, and in older texts an association neuron.
Intercalary Adj.— 1. Intended for insertion, insertion.
Explanatory Dictionary by Efremova
Neuron M.— 1. Same as: neuron.
Explanatory Dictionary by Efremova
Insertable- (shn), insertion, insertion. Adj. to insert.
Ushakov's Explanatory Dictionary
Neuron- neuron, m. (Greek neuron - fiber, nerve) (anat.). Nerve cell.
Ushakov's Explanatory Dictionary
Neuron- -A; m. [from Greek. neuron - nerve] Special. A nerve cell with all the processes extending from it.
Kuznetsov's Explanatory Dictionary
Insertion Disc— (discus intercalatus, LNH) common name microscopic structures at the point of contact of adjacent myocardial muscle cells, ensuring their connection into muscle complexes and transmission......
Large medical dictionary
Motor Neuron— , a nerve cell that conducts information to EFFECTORS (usually muscles) from the CENTRAL NERVOUS SYSTEM (CNS), thus causing the appropriate response. Axons (processes,........
Neuron— (nerve cell), the main structural and functional unit of the NERVOUS SYSTEM, which carries out the rapid transmission of NERVE IMPULSES between various organs. Consists of........
Scientific and technical encyclopedic dictionary
Sensory Neuron- (sensitive neuron), a nerve cell that conducts information from RECEPTORS in any part of the body to the CENTRAL NERVOUS SYSTEM (CNS). Their nerve endings are in.......
Scientific and technical encyclopedic dictionary
Neuron— (neuronum, neurocytus, LNH; Greek neuron vein, nerve; synonym: nerve cell, neurocyte, neurocyte) a cell capable of perceiving irritation, becoming excited, producing.......
Large medical dictionary
Neuron Amacrine- (n. amacrinum, LNH) N., located in the inner granular layer of the retina and providing communication between the neurons of this layer.
Large medical dictionary
Neuron Associative— see Intercalary neuron.
Large medical dictionary
Neuron Afferent- (n. afferens, n. sensorium: synonym: N. receptor, N. sensory, N. sensitive) N., which carries out the perception and transmission of excitation from receptors to other N. central nervous system.
Large medical dictionary
Neuron Bipolar- (n. bipolare, LNH) N., having two processes - an axon and a dendrite.
Large medical dictionary
Neuron Vegetative- the general name of N., which are part of the ganglia, plexuses and nerves of the autonomic nervous system.
Large medical dictionary
Neuron Fusiform— (n. fusiforme, LNH) multipolar intercalary N. of elongated shape, found in the molecular plate of the cerebral cortex.
Large medical dictionary
Neuron Fusiform Horizontal- (n. fusiforme horizontale, LNH) multipolar N. of an elongated shape, found mainly between the layer of piriform neurons and the granular layer of the cerebellar cortex.
Large medical dictionary
Neuron Internal- (n. internum, LNH) N. internal departments anterior horn spinal cord, the axon of which passes through the white commissure to the opposite half of the spinal cord.
Large medical dictionary
Neuron Intercalary— (n. intercalatum; synonym: N. associative, N. intermediate) N. involved in the transmission of excitation from afferent N. to efferent.
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Neuron Input- a formal neuron that performs in a specific system of neurons ( neural network) input function, i.e., perceiving signals only from the environment external to a given system.
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Neuron Gigantopyramidal- (n. gigantopyramidale, LNH; synonym: Betsa cell, giant pyramidal cell) large pyramidal N. of the internal pyramidal plate of the cerebral cortex; axons of the N. g. form........
Large medical dictionary
Neuron Horizontal— (n. horizomale, LNH) 1) N. inner granular layer of the retina, the processes of which contact the central endings of photoreceptor cells, carrying out redistribution........
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Neuron Piriform- (n. piriforme, LNH; synonym Purkinje cell) efferent N. of the cerebellar cortex, located in its ganglion layer and having a pear-shaped shape.
Large medical dictionary
Neuron Motor— see Motor neuron.
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Neuron Long axon— (n. longiaxonicum, LNH; synonym for Dogel cell type I) multipolar vegetative N., the axon of which transmits impulses to smooth or cardiac muscle tissue.
Large medical dictionary
Neuron Stellate- (n. stellatum, LNH) intercalated N. star-shaped.
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Neuron Stellate Long-axon- (n. stellatum longiaxonicum, LNH) N. z., located in the granular layer of the cerebellar cortex, having an axon extending into the white matter.
Large medical dictionary
Neuron Stellate Short Axon- (n. stellatum breviaxonicum, LNH) N. z. granular layer of the cerebellar cortex, which has an axon going to the cerebellar glomeruli.
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Neuron Granular- (n. granulare, LNH) the general name of small N. round, angular and pyramidal in shape, located in the outer granular plate of the cerebral cortex, the dendrites of which rise......
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Neuron Granular Large— (granoneurocytus magnus, LNH) the general name of large N., located in the molecular layer of the cerebellar cortex, the dendrites of which spread in the molecular layer, and the axons go to the granular layer.......
Large medical dictionary
What are they for? Why are there so many of them? What is a sensory neuron? What function do intercalary and executive neurons perform? Let's take a closer look at these amazing cells.
Every second, many signals pass through our brain. The process does not stop even in sleep. The body needs to accept the world around us, perform movements, ensure the functioning of the heart, respiratory, digestive, genitourinary system etc. Two main groups of neurons are involved in organizing all this activity - sensory and motor.
When we touch cold or hot and feel the temperature of the object, this is the merit of the sensitive cells. They instantly transmit information received from the periphery of the body. This ensures reflex activity.
Neurons form our entire central nervous system. Their main tasks:
These unique cells are capable of instantly transmitting electrical impulses.
To ensure the process of life, the body must process a huge amount of information that comes to it from the outside world, and respond to any sign of changing environmental conditions. To make this process as efficient as possible, neurons are divided according to their functions into:
The receptors themselves are cells of the skin, muscles, internal organs, and joints specially designated for this function. Receptors can begin in the cells of the epidermis and mucous membrane. They are able to accurately capture the smallest changes, both outside the body and inside it. Such changes may be physical or chemical. Then they are instantly transformed into special bioelectric impulses and sent directly to sensory neurons. This is how the signal travels from the periphery to the center of the body, where the brain deciphers its meaning.
Impulses from the organ to the brain are carried out by all three groups of neurons - motor, sensory and intermediate. The human nervous system consists of these groups of cells. This structure allows you to respond to signals from the outside world. They provide reflex activity body.
If a person ceases to feel taste, smell, hearing and vision decrease, this may indicate disorders in the central nervous system. Depending on which sense organs are affected, a neurologist can determine in which part of the brain the problems have arisen.
1) Somatic. This is conscious control of the skeletal muscles.
2) Vegetative (autonomous). This is uncontrollable control internal organs. The operation of this system occurs even if a person is in a state of sleep.
Sensory neurons are most often unipolar. This means that they are equipped with only one bifurcating process. It leaves the cell body (soma) and simultaneously performs the functions of both an axon and a dendrite. The axon is the input, and the dendrite of the sensory neuron is the output. After excitation of sensitive sensory cells, a bioelectric signal passes along the axon and dendrite.
There are also bipolar nerve cells that have two processes, respectively. They can be found, for example, in the retina and structures of the inner ear.
The body of the sensitive cell is shaped like a spindle. 1, and more often 2 processes (central and peripheral) extend from the body.
Peripheral in its shape is very similar to a thick long stick. It reaches the surface of the mucous membrane or skin. This process looks like a dendrite nerve cells.
The second, opposite process extends from the opposite part of the cell body and is shaped like a thin thread covered with swellings (they are called varicosities). This is an analogue of the nerve process of a neuron. This process is directed to a specific part of the central nervous system and thus branches.
Sensitive cells are also called peripheral. Their peculiarity is that they are located directly behind the peripheral nervous system and the central nervous system, but without them the operation of these systems is unthinkable. For example, olfactory cells are located in the epithelium of the nasal mucosa.
The function of a sensitive neuron is to receive a signal from special receptors located on the periphery of the body and determine its characteristics. The impulses are perceived by the peripheral processes of sensory neurons, then they are transmitted to their body, and then along the central processes they follow directly to the central nervous system.
The dendrites of sensory neurons connect to various receptors, and their axons connect to other neurons (interneurons). For a nerve impulse, the simplest path is the following - it must pass through three neurons: sensory, intercalary, motor.
The most typical example of the passage of an impulse is when a neurologist knocks on a knee joint. In this case, a simple reflex is immediately triggered: the knee tendon, after a blow to it, sets in motion the muscle that is attached to it; Sensitive cells from the muscle transmit the signal through sensory neurons directly to the spinal cord. There, sensory neurons make contact with motor neurons, and they send impulses back to the muscle, causing it to contract, and the leg straightens.
By the way, in each section of the spinal cord (cervical, thoracic, lumbar, sacral, coccygeal) there is a pair of roots: sensory posterior, motor anterior. They form a single trunk. Each of these pairs controls its own specific part of the body and sends a centrifugal signal about what to do next, how to position a limb, torso, what to do to the gland, etc.
Sensory neurons take part in the work reflex arc. It consists of 5 elements:
Biology human body very thought out and perfect. Thanks to the activity of many sensory neurons, we can interact with this amazing world, react to it. Our body is very susceptible, the development of its receptors and sensitive nerve cells has reached the highest level. Thanks to such a thoughtful organization of the central nervous system, our senses can perceive and transmit the smallest shades of taste, smell, tactile sensations, sound, color.
We often believe that the main thing in our consciousness and body activity is the cortex and hemispheres of the brain. At the same time, we forget what enormous capabilities the spinal cord provides. It is the functioning of the spinal cord that ensures the receipt of signals from all receptors.
It is difficult to name the limit of these possibilities. Our body is very plastic. The more a person develops, the more possibilities placed at his disposal. This simple principle allows us to quickly adapt to changes in the world around us.
A neuron is specific, electrically excitable cell in the human nervous system and has unique features. Its functions are to process, store and transmit information. Neurons are characterized complex structure and narrow specialization. They are also divided into three types. This article describes in detail the interneuron and its role in the action of the central nervous system.
The human brain has approximately 65 billion neurons that constantly communicate with each other. These cells are divided into several types, each of which performs its own special functions.
The sensory neuron plays the role of a transmitter of information between the sense organs and central departments human nervous system. It perceives a variety of irritations, which it converts into nerve impulses, and then transmits the signal to the human brain.
Motor - sends impulses to various organs and tissues. This type is mainly involved in the control of spinal cord reflexes.
The interneuron is responsible for processing and switching impulses. The functions of this type of cell are to receive and process information from the sensory and motor neurons between which they are located. Moreover, interneurons (or intermediate) neurons occupy 90% of the human central nervous system, and are also found in large quantities in all areas of the brain and spinal cord.
An interneuron consists of a body, an axon and dendrites. Each part has its own specific functions and is responsible for a specific action. Its body contains all the components from which cellular structures are created. The important role of this part of the neuron is to generate nerve impulses and performing trophic function. The elongated process that carries the signal from the cell body is called an axon. It is divided into two types: myelinated and non-myelinated. At the end of the axon there are various synapses. The third component of neurons is dendrites. They are short shoots that branch into different sides. Their function is to deliver impulses to the neuron body, which ensures communication between various types neurons of the central nervous system.
What determines the area of influence of an interneuron? First of all, his own structure. Basically, cells of this type have axons whose synapses end on neurons of the same center, which ensures their unification. Some interneurons are activated by others, from other centers, and then deliver information to their neural center. Such actions increase the impact of the signal, which is repeated in parallel paths, thereby extending the storage period of information data in the center. As a result, the location where the signal was delivered increases the reliability of the influence on the executive structure. Other interneurons can receive activation from connections of motor “brothers” from their center. Then they become transmitters of information back to their center, thereby creating feedback connections. Thus, the interneuron plays an important role in the formation of special closed networks that extend the storage period of information in the nerve center.
Interneurons are divided into two types: excitatory and inhibitory. When the former are activated, the transfer of data from one neural group to another is facilitated. This task is performed by “slow” neurons, which have the ability to activate for a long time. They transmit signals for quite a long time. In parallel with these actions, intermediate neurons activate their “fast” “colleagues”. When the activity of “slow” neurons increases, the reaction time of “fast” ones decreases. At the same time, the latter somewhat slow down the work of the “slow” ones.
An inhibitory interneuron comes into an active state due to direct signals that enter or emanate from their center. This action occurs by feedback. Direct excitation of this type of interneurons is characteristic of the intermediate centers of the sensory pathways of the spinal cord. And in the motor centers of the cerebral cortex, interneurons are activated due to feedback.
In the functioning of the human spinal cord, an important role is played by the conduction pathways, which are located outside the bundles that perform the conduction function. It is along these paths that the impulses sent by the intercalary and sensory neurons move. Signals travel up and down these pathways, conveying various information to the corresponding parts of the brain. Interneurons of the spinal cord are located in the intermediate medial nucleus, which, in turn, is located in posterior horn. Interneurons are an important anterior part of the spinocerebellar tract. On back side The horns of the spinal cord contain fibers consisting of interneurons. They form the lateral spinothalamic tract, which performs a special function. It is a conductor, that is, it transmits signals about pain and temperature sensitivity, first in the diencephalon, and then in the cerebral cortex itself.
In the human nervous system, interneurons perform a special and extremely important function. They connect with each other various groups nerve cells transmit signals from the brain to the spinal cord. Although this type is the smallest in size. The shape of the interneurons resembles a star. The bulk of these elements are located in the gray matter of the brain, and their processes do not protrude beyond the human central nervous system.
