Neuron. The structure of the nerve cell

Neuron is the structural and functional unit of the nervous tissue. This is a specialized cell, which, along with general physiological properties (excitability, conductivity), also has a number of specific properties:

- Perceive information- translate the information of the stimulus into the biological language of the cell.

- Process information- i.e. carry out information analysis, synthesis - connection of various parts of information after analysis to obtain a new quality.

- encode information- convert information into a form convenient for storage in the brain.

- Form a team a control signal that spreads to other cells, neurons, muscle cells.

- Transfer of information neuron to other structures.

Neurons are able to communicate with other cells and have an informational impact on them (the place of contacts is the synapse).

All of its activities are carried out by the neuron count of 3 physiological properties (in addition to excitability and conductivity):

reception;

electrogenesis;

Neurosecretion.

AT general plan , all neurons have a body - a soma and processes - dendrites and axons.

They are conditionally divided by structure and functions into the following groups:

By body shape: polygonal, pyramidal, round, oval.

By the number and nature of the processes:

Unipolar- having one branch

Pseudounipolar- one process departs from the body, which then divides into 2 branches.

Bipolar- 2 processes, one dendritic, the other axon.

Multipolar- have 1 axon and many dendrites.

According to the mediator released by the neuron in the synapse: cholinergic, adrenergic, serotonergic, peptidergic, etc.

By function:

afferent, or sensitive - serve to perceive signals from the external and internal environment and transmit them to the central nervous system.

Insertion, or interneurons, intermediate - provide processing, storage and transmission of information to efferent neurons. Most of them are in the CNS.

Efferent or motor - form control signals, and transmit them to peripheral neurons and executive organs.

According to the physiological role: excitatory and inhibitory.

General neuron functions The central nervous system is the reception, coding, storage of information and the production of a neurotransmitter. Neurons, with the help of numerous synapses, receive signals in the form of postsynaptic potentials. Then they process this information and form a certain response. Consequently, they also perform an integrative, i.e. unifying function.

Communication between neurons, as can be seen, is carried out through the gap between the ends of the axon of one neuron and the dendrites of another. If they lie in sufficient proximity, i.e., the gap is small, then a synaptic node, or a synapse, connecting these two neurons, can form in this place.

Synapse similar to the resistance electrical circuit. If this resistance is high, then the connection between neurons is weak and the excitation of one neuron does not cause the excitation of another. If the “resistance” of the synapse is small, then there is a strong connection and the neuron is easily excited from the axon of another neuron connected to it.
The excitation of the neuron occurs according to the principle of "all or nothing". This means that a neuron can either be excited, and a nerve impulse goes from the cell along the axon to the synaptic nodes and then to other neurons, or it is not excited.

2. Humoral regulation. Functions, mechanisms of interaction of humoral substances with target cells. The place and role of the endocrine glands in the regulation of function.

Humoral regulation- one of the evolutionary early mechanisms of regulation of vital processes in the body, carried out through the liquid media of the body (blood, lymph, tissue fluid, oral cavity) with the help of hormones secreted by cells, organs, tissues. In highly developed animals, including humans, humoral regulation is subordinate to nervous regulation and, together with it, constitutes a single system of neurohumoral regulation. Metabolic products act not only directly on the effector organs, but also on the endings of sensory nerves (chemoreceptors) and nerve centers, causing certain reactions by humoral or reflex means. Humoral transmission of nerve impulses chemicals, mediators, is carried out in the central and peripheral nervous system. Along with hormones, products of intermediate metabolism play an important role in humoral regulation.

Biological activity liquid media the body is determined by the ratio of the content of catecholamines (adrenaline and norepinephrine, their precursors and decay products), acetylcholine, histamine, serotonin and other biogenic amines, some polypeptides and amino acids, the state of enzyme systems, the presence of activators and inhibitors, the content of ions, trace elements, etc.

Depending on the structure of the hormone, there are two types of interaction. If the hormone molecule lipophilic(for example, steroid hormones), then it can penetrate the lipid layer of the outer membrane of target cells. If the molecule is large or polar, then its penetration into the cell is impossible. Therefore, for lipophilic hormones, receptors are located inside target cells, and for hydrophilic The receptors are located in the outer membrane.

To get a cellular response the hormonal signal in the case of hydrophilic molecules is affected by an intracellular signal transduction mechanism. This happens with the participation of substances, which are called second intermediaries. Hormone molecules are very diverse in shape, but "second messengers" are not. The reliability of signal transmission provides a very high affinity of the hormone for its receptor protein.

Intermediaries- these are cyclic nucleotides (cAMP and cGMP), inositol triphosphate, calcium-binding protein - calmodulin, calcium ions, enzymes involved in the synthesis of cyclic nucleotides, as well as protein kinases - protein phosphorylation enzymes. All these substances are involved in the regulation of the activity of individual enzyme systems in target cells.

Exist two main ways of transmitting a signal to cells - targets from signaling molecules with a membrane mechanism of action: adenylate cyclase (or guanylate cyclase) systems; and phosphoinositide mechanism.

Cyclase system - it is a system consisting of adenosine cyclophosphate, adenylate cyclase and phosphodiesterase contained in the cell, which regulates the permeability of cell membranes, is involved in the regulation of many metabolic processes of a living cell, and mediates the action of certain hormones. That is, the role of the cyclase system is that they are the second mediators in the mechanism of action of hormones.

System "adenylate cyclase - cAMP". The membrane enzyme adenylate cyclase can be in two forms - activated and inactivated. Adenylate cyclase is activated under the influence of a hormone-receptor complex, the formation of which leads to the binding of guanyl nucleotide (GTP) to a specific regulatory stimulating protein (GS protein), after which the GS protein causes magnesium to attach to adenylate cyclase and activate it. This is how the hormones glucagon, thyrotropin, parathyrin, vasopressin, gonadotropin, etc., which activate adenylate cyclase, act. Some hormones, on the contrary, suppress adenylate cyclase (somatostatin, angiotensin-P, etc.)

Under the influence of adenylate cyclase cAMP is synthesized from ATP, causing the activation of protein kinases in the cytoplasm of the cell, which ensure the phosphorylation of numerous intracellular proteins. This changes the permeability of the membranes, i.e. causes metabolic and, accordingly, functional shifts typical for the hormone. The intracellular effects of cAMP are also manifested in the influence on the processes of proliferation, differentiation, and on the availability of membrane receptor proteins to hormone molecules.

Guanylate cyclase-cGMP system. Activation of membrane guanylate cyclase occurs not under the direct influence of the hormone-receptor complex, but indirectly through ionized calcium and oxidant systems of membranes. This is how atrial natriuretic hormone, an atriopeptide, a tissue hormone of the vascular wall, realizes its effects. In most tissues, the biochemical and physiological effects of cAMP and cGMP are opposite. Examples are the stimulation of heart contractions under the influence of cAMP and their inhibition by cGMP, the stimulation of contractions of intestinal smooth muscles by cGMP and the suppression of cAMP.

In addition to the adenylate cyclase or guanylate cyclase systems, there is also a mechanism for information transfer inside the target cell with the participation of calcium ions and inositol triphosphate.

Inositol triphosphate - this substance, which is a derivative of a complex lipid - inositol phosphatide. It is formed as a result of the action of a special enzyme - phospholipase "C", which is activated as a result of conformational changes in the intracellular domain of the membrane receptor protein. This enzyme hydrolyzes the phosphoester bond in the phosphatidyl-inositol-4,5-bisphosphate molecule, resulting in the formation of diacylglycerol and inositol triphosphate.

It is known that education diacylglycerol and inositol triphosphate leads to an increase in the concentration of ionized calcium inside the cell. This leads to the activation of many calcium-dependent proteins inside the cell, including the activation of various protein kinases. And here, as in the case of activation of the adenylate cyclase system, one of the stages of signal transmission inside the cell is protein phosphorylation, which leads to a physiological response of the cell to the action of the hormone.

In work phosphoinositide mechanism signaling in the target cell involves a special calcium-binding protein - calmodulin. This is a low molecular weight protein (17 kDa), 30% consisting of negatively charged amino acids (Glu, Asp) and therefore capable of actively binding Ca + 2. One calmodulin molecule has 4 calcium-binding sites. After interaction with Ca + 2, conformational changes in the calmodulin molecule occur and the Ca + 2-calmodulin complex becomes able to regulate the activity (allosterically inhibit or activate) many enzymes - adenylate cyclase, phosphodiesterase, Ca + 2, Mg + 2-ATPase and various protein kinases.

in different cells under the influence of the Ca + 2-calmodulin complex on isoenzymes of the same enzyme (for example, on adenylate cyclase of different types), in some cases, activation is observed, and in others, inhibition of the cAMP formation reaction. Such different effects occur because the allosteric centers of isoenzymes can include different amino acid radicals and their response to the action of the Ca + 2-calmodulin complex will be different.

Thus, in the role "second intermediaries" for signaling from hormones in target cells can be: cyclic nucleotides (c-AMP and c-GMP); Ca ions; complex "Sa-calmodulin"; diacylglycerol; inositol triphosphate.

The mechanisms for transmitting information from hormones inside target cells with the help of these mediators have common features : one of the steps in signal transduction is protein phosphorylation; termination of activation occurs as a result of special mechanisms initiated by the participants in the processes themselves - there are mechanisms of negative feedback.

Hormones are the main humoral regulators of the physiological functions of the body, and their properties, biosynthesis processes and mechanisms of action are now well known. Hormones are highly specific substances with respect to target cells and have a very high biological activity.

Endocrine glands - specialized organs that do not have excretory ducts and secrete into the blood, cerebral fluid, lymph through the intercellular gaps.

The physiological role of the endocrine glands associated with their influence on the mechanisms of regulation and integration, adaptation, maintaining the constancy of the internal environment of the body.

- (from the Greek neuron nerve) a nerve cell consisting of a body and processes extending from it with relatively short dendrites and a long axon; the main structural and functional unit of the nervous system (see diagram). Neurons conduct nerve impulses... Big Encyclopedic Dictionary

Afferent neuron- (sensitive, sensory) - a neuron that receives signals from receptors of the external and internal environment, transmits impulses to other neurons (associative, efferent) C.N.S ... Glossary of terms for the physiology of farm animals

BUT; m. [from Greek. neuron nerve] Spec. Nerve cell with all processes extending from it. * * * neuron (from the Greek néuron nerve), a nerve cell consisting of a body and processes extending from it with relatively short dendrites and a long axon; ... ... encyclopedic Dictionary

This term has other meanings, see Neuron (meanings). Not to be confused with neutron. Pyramidal neuron of the mouse cerebral cortex, expressive green fluorescent protein (GFP) Neuron (from ... Wikipedia

- (n. afferens, n. sensorium: synonym: N. receptor, N. sensory, N. sensitive) N., which perceives and transmits excitation from receptors to other N. of the central nervous system ... Big Medical Dictionary

- (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 located in the sense organs. see also MOTOR NEURON, NEURON, FEELINGS, NERVE ... Scientific and technical encyclopedic dictionary

A complex network of structures that permeates the entire body and ensures self-regulation of its vital activity due to the ability to respond to external and internal influences (stimuli). The main functions of the nervous system are receiving, storing and ... ... Collier Encyclopedia

Not to be confused with neutron. Pyramidal neuron cells in the mouse cerebral cortex A neuron (nerve cell) is a structural and functional unit of the nervous system. This cell has a complex structure, and is highly specialized in structure ... ... Wikipedia

Not to be confused with neutron. Pyramidal neuron cells in the mouse cerebral cortex A neuron (nerve cell) is a structural and functional unit of the nervous system. This cell has a complex structure, and is highly specialized in structure ... ... Wikipedia

This cell has a complex structure, is highly specialized and contains a nucleus, a cell body and processes in structure. There are over one hundred billion neurons in the human body.

Review

The complexity and diversity of the functions of the nervous system are determined by the interaction between neurons, which, in turn, are a set of different signals transmitted as part of the interaction of neurons with other neurons or muscles and glands. Signals are emitted and propagated by ions that generate electric charge, which moves along the neuron.

Structure

The neuron consists of a body with a diameter of 3 to 130 microns, containing a nucleus (with a large number of nuclear pores) and organelles (including a highly developed rough ER with active ribosomes, the Golgi apparatus), as well as processes. There are two types of processes: dendrites and. The neuron has a developed and complex cytoskeleton that penetrates into its processes. The cytoskeleton maintains the shape of the cell, its threads serve as "rails" for the transport of organelles and substances packed in membrane vesicles (for example, neurotransmitters). The cytoskeleton of a neuron consists of fibrils of different diameters: Microtubules (D = 20-30 nm) - consist of the protein tubulin and stretch from the neuron along the axon, up to the nerve endings. Neurofilaments (D = 10 nm) - together with microtubules provide intracellular transport of substances. Microfilaments (D = 5 nm) - consist of actin and myosin proteins, are especially pronounced in growing nerve processes and in. In the body of the neuron, a developed synthetic apparatus is revealed, the granular ER of the neuron stains basophilically and is known as the "tigroid". The tigroid penetrates into the initial sections of the dendrites, but is located at a noticeable distance from the beginning of the axon, which serves as a histological sign of the axon.

A distinction is made between anterograde (away from the body) and retrograde (towards the body) axon transport.

Dendrites and axon

An axon is usually a long process adapted to conduct from the body of a neuron. Dendrites are, as a rule, short and highly branched processes that serve as the main site for the formation of excitatory and inhibitory synapses that affect the neuron (different neurons have a different ratio of the length of the axon and dendrites). A neuron may have several dendrites and usually only one axon. One neuron can have connections with many (up to 20 thousand) other neurons.

Dendrites divide dichotomously, while axons give rise to collaterals. The branch nodes usually contain mitochondria.

Dendrites do not have a myelin sheath, but axons can. The place of generation of excitation in most neurons is the axon hillock - a formation at the place where the axon leaves the body. In all neurons, this zone is called the trigger zone.

Synapse(Greek σύναψις, from συνάπτειν - hug, embrace, shake hands) - the place of contact between two neurons or between a neuron and the effector cell receiving the signal. Serves for transmission between two cells, and during synaptic transmission, the amplitude and frequency of the signal can be regulated. Some synapses cause neuron depolarization, others hyperpolarization; the former are excitatory, the latter are inhibitory. Usually, to excite a neuron, stimulation from several excitatory synapses is necessary.

The term was introduced in 1897 by the English physiologist Charles Sherrington.

Classification

Structural classification

Based on the number and arrangement of dendrites and axons, neurons are divided into non-axonal, unipolar neurons, pseudo-unipolar neurons, bipolar neurons, and multipolar (many dendritic trunks, usually efferent) neurons.

Axonless neurons- small cells, grouped close in the intervertebral ganglia, having no anatomical signs of division of processes into dendrites and axons. All processes in a cell are very similar. The functional purpose of axonless neurons is poorly understood.

Unipolar neurons- neurons with one process, are present, for example, in the sensory nucleus of the trigeminal nerve in.

bipolar neurons- neurons with one axon and one dendrite, located in specialized sensory organs - the retina, olfactory epithelium and bulb, auditory and vestibular ganglia.

Multipolar neurons- Neurons with one axon and several dendrites. This type of nerve cells predominates in.

Pseudo-unipolar neurons- are unique in their kind. One process departs from the body, which immediately divides in a T-shape. This entire single tract is covered with a myelin sheath and structurally represents an axon, although along one of the branches, excitation goes not from, but to the body of the neuron. Structurally, dendrites are ramifications at the end of this (peripheral) process. The trigger zone is the beginning of this branching (that is, it is located outside the cell body). Such neurons are found in the spinal ganglia.

Functional classification

By position in the reflex arc, afferent neurons (sensitive neurons), efferent neurons (some of them are called motor neurons, sometimes this is not a very accurate name applies to the entire group of efferents) and interneurons (intercalary neurons) are distinguished.

Afferent neurons(sensitive, sensory or receptor). To neurons of this type include primary cells and pseudo-unipolar cells, in which dendrites have free endings.

Efferent neurons(effector, motor or motor). Neurons of this type include final neurons - ultimatum and penultimate - not ultimatum.

Associative neurons(intercalary or interneurons) - a group of neurons communicates between efferent and afferent, they are divided into intrusion, commissural and projection.

secretory neurons- neurons that secrete highly active substances (neurohormones). They have a well-developed Golgi complex, the axon ends in axovasal synapses.

Morphological classification

The morphological structure of neurons is diverse. In this regard, when classifying neurons, several principles are used:

• take into account the size and shape of the body of the neuron;
• the number and nature of branching processes;
• the length of the neuron and the presence of specialized membranes.

According to the shape of the cell, neurons can be spherical, granular, stellate, pyramidal, pear-shaped, fusiform, irregular, etc. The size of the neuron body varies from 5 microns in small granular cells to 120-150 microns in giant pyramidal neurons. The length of a human neuron ranges from 150 microns to 120 cm.

According to the number of processes, the following morphological types of neurons are distinguished:

• unipolar (with one process) neurocytes present, for example, in the sensory nucleus of the trigeminal nerve in;
• pseudo-unipolar cells clustered nearby in the intervertebral ganglia;
• bipolar neurons (have one axon and one dendrite) located in specialized sensory organs - the retina, olfactory epithelium and bulb, auditory and vestibular ganglia;
• multipolar neurons (have one axon and several dendrites), predominant in the CNS.

Development and growth of a neuron

The neuron develops from a small progenitor cell that stops dividing even before it releases its processes. (However, the issue of neuronal division is currently debatable) As a rule, the axon begins to grow first, and dendrites form later. A thickening appears at the end of the developing process of the nerve cell irregular shape, which, apparently, paves the way through the surrounding tissue. This thickening is called the growth cone of the nerve cell. It consists of a flattened part of the process of the nerve cell with many thin spines. The microspinules are 0.1 to 0.2 µm thick and can be up to 50 µm in length; the wide and flat area of ​​the growth cone is about 5 µm wide and long, although its shape may vary. The spaces between the microspines of the growth cone are covered with a folded membrane. Microspines are in constant motion - some are drawn into the growth cone, others elongate, deviate in different directions, touch the substrate and can stick to it.

The growth cone is filled with small, sometimes interconnected, irregularly shaped membranous vesicles. Directly under the folded areas of the membrane and in the spines is a dense mass of entangled actin filaments. The growth cone also contains mitochondria, microtubules, and neurofilaments found in the body of the neuron.

Probably, microtubules and neurofilaments are elongated mainly due to the addition of newly synthesized subunits at the base of the neuron process. They move at a speed of about a millimeter per day, which corresponds to the speed of slow axon transport in a mature neuron. Since the average rate of advance of the growth cone is approximately the same, it is possible that neither assembly nor destruction of microtubules and neurofilaments occurs at the far end of the neuron process during the growth of the neuron process. New membrane material is added, apparently, at the end. The growth cone is an area of ​​rapid exocytosis and endocytosis, as evidenced by the many vesicles present here. Small membrane vesicles are transported along the process of the neuron from the cell body to the growth cone with a stream of fast axon transport. Membrane material is apparently synthesized in the body of the neuron, transported to the growth cone in the form of vesicles, and incorporated here into the plasma membrane by exocytosis, thus lengthening the outgrowth of the nerve cell.

The growth of axons and dendrites is usually preceded by a phase of neuronal migration, when immature neurons settle and find a permanent place for themselves.

1) central- dorsal and
2) peripheral- nerves and ganglions.

• Nerves are bundles of nerve fibers surrounded by a connective tissue sheath.
• Nerve nodes are clusters of neuron bodies outside the CNS, such as the solar plexus.

The nervous system is divided into two parts

1) somatic- controls skeletal muscles, obeys consciousness.
2) vegetative (autonomous)- manages internal organs, does not obey consciousness. Consists of two parts:

• sympathetic: controls organs during times of stress and exercise
• increases heart rate, blood pressure and blood glucose levels
• activates the nervous system and sensory organs
• dilates the bronchi and pupil
• slows down the digestive system.
• parasympathetic the system works at rest, brings the work of the organs back to normal (opposite functions).

reflex arc

This is the path along which the nerve impulse passes during implementation. Consists of 5 parts
1) Receptor- a sensitive formation capable of responding to a certain type of stimulus; converts irritation into a nerve impulse.
2) By sensitive neuron the nerve impulse goes from the receptor to the central nervous system (spinal cord or brain).
3) Interneuron located in the brain, transmits a signal from a sensitive neuron to an executive one.
4) By executive (motor) neuron nerve impulse goes from the brain to the working organ.
5) Working (executive) body- muscle (contracts), gland (secrets), etc.

Analyzer

This is a system of neurons that perceive irritation, conduct nerve impulses and provide information processing. Consists of 3 departments:
1) peripheral- these are receptors, for example, cones and rods in the retina of the eye
2) conductive are the nerves and pathways of the brain
3) central located in the cortex - here the final analysis of information takes place.

Choose the one most correct option. The department of the auditory analyzer, which transmits nerve impulses to the human brain, is formed
1) auditory nerves
2) receptors located in the cochlea
3) eardrum
4) auditory ossicles

Answer

Choose three correct answers from six and write down the numbers under which they are indicated. What examples illustrate the excitation of the sympathetic nervous system?
1) increased heart rate
2) increased intestinal motility
3) lowering blood pressure
4) dilation of the pupils of the eyes
5) increase in blood sugar
6) narrowing of the bronchi and bronchioles

Answer

Choose three correct answers from six and write down the numbers under which they are indicated. What effect does the parasympathetic nervous system have on the human body?
1) increases the heart rate
2) activates salivation
3) stimulates the production of adrenaline
4) enhances the formation of bile
5) increases intestinal peristalsis
6) mobilizes the functions of organs under stress

Answer

Choose one, the most correct option. Nerve impulses from receptors to the central nervous system conduct
1) sensitive neurons
2) motor neurons
3) sensory and motor neurons
4) intercalary and motor neurons

Answer

Choose three correct answers from six and write down the numbers under which they are indicated. Receptors are nerve endings in the human body that
1) perceive information from the external environment
2) perceive impulses from the internal environment
3) perceive excitation transmitted to them through motor neurons
4) are located in the executive body
5) convert perceived stimuli into nerve impulses
6) realize the body's response to irritation from the external and internal environment

Answer

Choose one, the most correct option. Peripheral part of the visual analyzer
1) optic nerve
2) visual receptors
3) pupil and lens
4) visual cortex

Answer

Choose one, the most correct option. Reflexes that cannot be enhanced or inhibited by the will of a person are carried out through the nervous system
1) central
2) vegetative
3) somatic
4) peripheral

Answer

1. Establish a correspondence between the feature of regulation and the department of the nervous system that implements it: 1) somatic, 2) vegetative
A) regulates the work of skeletal muscles
B) regulates metabolic processes
B) provides voluntary movements
D) is carried out autonomously, regardless of the desire of a person
D) controls the activity of smooth muscles

Answer

2. Establish a correspondence between the function of the human peripheral nervous system and the department that performs this function: 1) somatic, 2) vegetative
A) directs commands to skeletal muscles
B) innervates the smooth muscles of the internal organs
B) provides movement of the body in space
D) regulates the work of the heart
D) enhances the work of the digestive glands

Answer

3. Establish a correspondence between the characteristics and the department of the human nervous system: 1) somatic, 2) vegetative. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) directs commands to skeletal muscles
B) changes the activity of various glands
C) forms only a three-neuron reflex arc
D) changes the heart rate
D) causes voluntary body movements
E) regulates smooth muscle contraction

Answer

4. Establish a correspondence between the properties of the nervous system and its types: 1) somatic, 2) vegetative. Write down the numbers 1 and 2 in right order.
A) innervates the skin and skeletal muscles
B) innervates all internal organs
C) actions are not subject to consciousness (autonomous)
D) actions are controlled by consciousness (arbitrary)
D) helps to maintain the connection of the body with the external environment
E) regulates metabolic processes, body growth

Answer

5. Establish a correspondence between the types of the nervous system and their characteristics: 1) vegetative, 2) somatic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) regulates the work of internal organs
B) regulates the work of skeletal muscles
C) reflexes are carried out quickly and obey the human mind
D) reflexes are slow and do not obey human consciousness
D) the highest organ of this system is the hypothalamus
E) the highest center of this system is the cerebral cortex

Answer

6n. Establish a correspondence between the characteristic and the department of the human nervous system to which it belongs: 1) somatic, 2) vegetative. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) regulates the diameter of blood vessels
B) has a reflex arc motor pathway, consisting of two neurons
B) provides a variety of body movements
D) works arbitrarily
D) supports the activity of internal organs

Answer

Establish a correspondence between the organs and types of the nervous system that control their activity: 1) somatic, 2) vegetative. Write the numbers 1 and 2 in the correct order.
A) bladder
B) liver
B) biceps
D) intercostal muscles
D) intestines
E) oculomotor muscles

Answer

Choose three options. Hearing analyzer includes
1) auditory ossicles
2) receptor cells
3) auditory tube
4) sensory nerve
5) semicircular canals
6) cortex of the temporal lobe

Answer

Choose one, the most correct option. Nerve impulses are transmitted to the brain through neurons
1) motor
2) insert
3) sensitive
4) executive

Answer

Choose three consequences of irritation of the sympathetic department of the central nervous system:
1) increased and increased heart contractions
2) slowing down and weakening of heart contractions
3) slowing down the formation of gastric juice
4) increased intensity of activity of the stomach glands
5) weakening of the wave-like contractions of the intestinal walls
6) strengthening of undulating contractions of the intestinal walls

Answer

1. Establish a correspondence between the function of organs and the department of the autonomic nervous system that performs it: 1) sympathetic, 2) parasympathetic
A) increased secretion of digestive juices
B) slow heart rate
B) increased ventilation of the lungs
D) pupil dilation
D) increased undulating bowel movements

Answer

2. Establish a correspondence between the function of organs and the department of the autonomic nervous system that performs it: 1) sympathetic, 2) parasympathetic
A) raises the heart rate
B) reduces the frequency of breathing
C) stimulates the secretion of digestive juices
D) stimulates the release of adrenaline into the blood
D) increases ventilation of the lungs

Answer

3. Establish a correspondence between the function of the autonomic nervous system and its department: 1) sympathetic, 2) parasympathetic
A) raises blood pressure
B) enhances the separation of digestive juices
B) lowers the heart rate
D) reduces intestinal peristalsis
D) increases blood flow in the muscles

Answer

4. Establish a correspondence between the functions and divisions of the autonomic nervous system: 1) sympathetic, 2) parasympathetic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) dilates the arteries
B) speeds up the heartbeat
C) enhances intestinal peristalsis and stimulates the digestive glands
D) constricts the bronchi and bronchioles, reduces ventilation of the lungs
D) dilated pupils

Answer

Choose one, the most correct option. What are nerves made up of?
1) an accumulation of nerve cells in the brain
2) clusters of nerve cells outside the central nervous system
3) nerve fibers with a connective tissue sheath
4) white matter located in the central nervous system

Answer

Choose three anatomical structures that are the initial link of human analyzers
1) eyelids with eyelashes
2) rods and cones of the retina
3) auricle
4) cells of the vestibular apparatus
5) lens of the eye
6) taste buds of the tongue

Answer

Choose one, the most correct option. A system of neurons that perceive stimuli, conduct nerve impulses and provide information processing is called
1) nerve fiber

3) nerve
4) analyzer

Answer

Choose one, the most correct option. What is the name of the system of neurons that perceive stimuli, conduct nerve impulses and provide information processing
1) nerve fiber
2) central nervous system
3) nerve
4) analyzer

Answer

Choose three options. The visual analyzer includes
1) the white of the eye
2) retinal receptors
3) vitreous body
4) sensory nerve
5) cortex of the occipital lobe
6) lens

Answer

Choose one, the most correct option. The peripheral part of the human auditory analyzer is formed by
1) ear canal and eardrum
2) bones of the middle ear
3) auditory nerves
4) sensitive snail cells

Answer

With excitation of the sympathetic nervous system, in contrast to excitation of the parasympathetic nervous system
1) arteries dilate
2) blood pressure rises
3) intestinal motility increases
4) the pupil narrows
5) increases the amount of sugar in the blood
6) heart contractions become more frequent

Answer

1. Set the sequence of parts of the reflex arc when a nerve impulse passes through it. Write down the corresponding sequence of numbers.
1) sensitive neuron
2) working body
3) intercalary neuron
4) department of the cerebral cortex
5) receptor
6) motor neuron

Answer

2. Establish the sequence of links in the reflex arc of the sweating reflex. Write down the corresponding sequence of numbers.
1) occurrence in the receptors of nerve impulses
2) sweating
3) excitation of motor neurons
4) irritation of skin receptors that perceive heat
5) transmission of nerve impulses to the sweat glands
6) transmission of nerve impulses along sensory neurons in the central nervous system

Answer

3. Establish the sequence of nerve impulse conduction in the reflex arc, which provides one of the mechanisms of thermoregulation in the human body. Write down the corresponding sequence of numbers.
1) transmission of a nerve impulse along a sensitive neuron to the central nervous system
2) transmission of a nerve impulse to motor neurons
3) excitation of skin thermoreceptors with a decrease in temperature
4) transmission of a nerve impulse to intercalary neurons
5) decrease in the lumen of the blood vessels of the skin

Answer

Choose three options. Interneurons in the human nervous system transmit nerve impulses
1) from a motor neuron to the brain
2) from the working body to the spinal cord
3) from the spinal cord to the brain
4) from sensitive neurons to working organs
5) from sensory neurons to motor neurons
6) from the brain to motor neurons

Answer

Arrange in the correct order the elements of the human knee reflex reflex arc. Write down the numbers in the answer in the order corresponding to the letters.
1) Motor neuron
2) Sensitive neuron
3) Back brain
4) Tendon receptors
5) Quadriceps femoris

Answer

Choose three functions of the sympathetic nervous system. Write down the numbers under which they are indicated.
1) enhances ventilation of the lungs
2) reduces heart rate
3) lowers blood pressure
4) inhibits the secretion of digestive juices
5) enhances intestinal motility
6) dilates pupils

Answer

Choose one, the most correct option. Sensory neurons in the three-neuron reflex arc are connected to
1) processes of intercalary neurons
2) bodies of intercalary neurons
3) motor neurons
4) executive neurons

Answer

Establish a correspondence between the functions and types of neurons: 1) sensitive, 2) intercalary, 3) motor. Write down the numbers 1, 2, 3 in the order corresponding to the letters.
A) transmission of nerve impulses from the sense organs to the brain
B) transmission of nerve impulses from internal organs to the brain
B) transmission of nerve impulses to muscles
D) transmission of nerve impulses to the glands
D) transmission of nerve impulses from one neuron to another

Answer

Choose three correct answers from six and write down the numbers under which they are indicated. What organs are controlled by the autonomic nervous system?
1) organs of the digestive tract
2) gonads
3) limb muscles
4) heart and blood vessels
5) intercostal muscles
6) chewing muscles

Answer

Choose three correct answers from six and write down the numbers under which they are indicated. The central nervous system is
1) sensory nerves
2) spinal cord
3) motor nerves
4) cerebellum
5) bridge
6) nerve nodes

Answer

Analyze the Neurons table. For each cell labeled with a letter, select the appropriate term from the list provided. © D.V. Pozdnyakov, 2009-2019