Cells make up all tissues, tissues make up organs, organs, systems and systems make up organisms. Cells are of different types that make up different tissues. Each of them has different characteristics, but the epithelium and connective tissues usually mix with each other. To distinguish the differences between the two, detailed explanations and descriptions are provided below.
Epithelial tissue
Common sense tells us that epithelial cells make up epithelial tissues. They are located in one or more layers. These include the inner and outer lining of body cavities such as skin, lungs, kidneys, mucous membranes, and so on. These cells are very close to each other and have a very small matrix among them. Tight junctions are located between the cells, which regulate the passage of substances. These tissues do not have blood vessels or capillaries, but they get their nutrients from the lower thin sheet of connective tissue known as the basement membrane.
∙ Types of epithelial tissue
Connective tissue
Connective tissues are composed of fibers that form a network and a semi-fluid intracellular matrix. This is where the blood vessels and nerves are embedded. It is responsible for the distribution of nutrients and oxygen to all tissues. It forms the skeleton, nerves, fat, blood, and muscle. It functions not only to support and protect, but also to bind other tissues that facilitate communication and transport. Besides adipose tissue, one type of connective tissue is responsible for providing heat to the body. Connective tissues are a vital and significant component of almost all organs in the body.
∙ Types of connective tissue
Epithelial and connective tissue
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Specifications | ||
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function |
Forms the outer and inner surfaces of organs. This tissue acts as a barrier that regulates substances that enter and exit surfaces. |
Connective tissues bind, protect, and support other tissues and organs. |
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Location |
Cells are located in one or more layers. |
The cells in the connective tissue are dispersed in the matrix. |
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Components |
It consists of epithelial cells and a small amount of intracellular matrix. |
It consists of cells and a large amount of intracellular matrix. |
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Blood capillaries |
The blood capillaries do not surround the tissue and they get their nutrients from the basement membrane. |
The connective tissues are surrounded by blood capillaries from which they receive their nutrients. |
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Location in relation to the foundation membrane |
Epithelial tissues are located above the basement membranes. |
The connective tissue is located below the basement membrane. |
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development |
Epithelial tissues develop from ectoderm, mesoderm and endoderm |
Connective tissues develop from the mesoderm. |
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Where can you find these fabrics? |
Skin, mucous membranes, glands, organs such as lungs, kidneys, |
Adipose, bone, ligaments, tendons, nerves, cartilage, muscles |
Epithelial tissue and connective tissue differ in different ways, but both work in conjunction with each other and among other tissue types. It's incredible that the body is made up of them, making all systems at their best. Examining the human body has made us realize how amazing it is, and we must support it by taking care of our well-being and staying healthy.
Question 1. What tissue does the skin, the walls of the mouth, ear and nasal cartilage consist of?
The skin, the walls of the oral cavity are composed of epithelial tissue, and the ear and nasal cartilages are composed of connective tissue.
Questions after the paragraph
Question 1. What is called a cloth?
Groups of cells and intercellular substance that have a similar structure and origin and perform common functions are called tissues.
Question 2. What kind of fabrics do you know? Draw up and fill in the Fabric Variety chart.
In the body of animals and humans, four main groups of tissues are distinguished: epithelial, connective, muscle and nervous. In muscles, for example, muscle tissue predominates, but along with it there are connective and nervous tissue. The tissue can consist of both the same and different cells.
Question 3. How are connective tissues different from epithelial ones?
The connective tissue contains cells capable of fighting microorganisms, and in case of damage to the main tissue of any organ, this tissue is able to replace the lost elements. So, the scars formed after wounds consist of connective tissue. True, it cannot perform the functions of the tissue that the connective tissue has replaced.
Question 4. What types of epithelial and connective tissue do you know?
Types of epithelial tissue: squamous epithelium, cubic epithelium, ciliated epithelium, columnar epithelium.
Connective tissues include supporting tissues - cartilaginous and bone; liquid tissues - blood and lymph, loose fibrous tissue that fills the space between organs, accompanying blood vessels and nerves; adipose tissue; dense fibrous tissue that is part of the tendons and ligaments.
Question 5. What properties do muscle tissue cells have - smooth, skeletal, cardiac?
The general properties of all muscle tissues are excitability and contractility. Muscle tissue contracts in response to irritation. Thanks to the reduction, all human movements and the work of his internal organs are carried out.
Question 6. What are the functions of neuroglial cells?
Neuroglial cells perform in relation to them serving functions: protective and supporting, nutritious and electrically insulating.
Question 7. What is the structure and properties of neurons?
A neuron consists of a body and processes. The body of a neuron contains the nucleus and the main cellular organelles. Neuron processes differ in structure, shape and function.
Question 8. Compare dendrites and axons. What are their similarities and what are the fundamental differences?
A dendrite is a process that transmits excitation to the body of a neuron. Most often, a neuron has several short branched dendrites. However, there are neurons that have only one long dendrite.
An axon is a long process that transfers information from the body of a neuron to the next neuron or to a working organ. Each neuron has only one axon. The axon branches only at the end, forming short branches - terminal and.
Question 9. What is a synapse? Tell us about how it works.
The points of contact between individual neurons or between neurons and the cells they control are called synapses.
In the extended end of the axon, in special vesicles - vesicles, there is a biologically active substance from the group of neurotransmitters. When the nerve impulse propagating along the axon reaches its end, the bubbles approach the membrane, are embedded in it, and the neurotransmitter molecules are thrown into the synaptic cleft. These chemicals act on the membrane of another cell and in this way transmit information to the next neuron or cell of the controlled organ. The neurotransmitter can activate the next cell, causing excitement in it. However, there are neurotransmitters that lead to the suppression of the next neuron. This process is called inhibition.
Excitation and inhibition are the most important processes in the nervous system. It is due to the balance of these two opposite processes at each moment of time that nerve impulses can arise only in a strictly defined group of nerve cells. Our attention, the ability to concentrate on a certain activity is possible thanks to neurons that cut off excess information. If it were not for them, our nervous system would overload very quickly and would not be able to work normally.
Tasks
1. Look for scars on the skin of yourself or someone you know. Determine what kind of fabric they are made of. Explain why they do not tan and are different in texture from healthy skin areas.
Scars are made up of connective tissue. These cells lack the melanin pigment, so these areas of the skin do not tan in the sun.
2. Look under a microscope at samples of epithelial and connective tissue. Using Figures 16 and 17, tell us about their structure.
The epithelial cell has a thick membrane (a small amount of intercellular substance). The connective tissue has a high ability to regenerate, (the main function is performed by the intercellular substance.
3. In Figure 20, locate the neuron body, nucleus, dendrites, and axon. Determine in which direction the nerve impulses will go along the processes if the cell is excited.
If the cell is excited, then the nerve impulse always moves from the cell body along the axon to the synapses.
4. It is known that the thoracic and abdominal cavities are separated by the diaphragm involved in breathing. Does it consist of smooth or striated muscles? Hold your breath, take an arbitrary breath in and out and answer this question.
The diaphragm is made up of muscle tissue. It is composed of smooth muscles.
5. There are many classifications of neurons. Some of them are already known to you. Using additional sources of information, suggest other classifications than those presented in the textbook.
Classification of neurons by the number of processes:
1. Multipolar neurons - neurons with multiple processes
2. Bipolar neurons - have 2 processes
3. Unipolar
a) Pseudo-unipolar (they have 1 process, although initially they are laid as double-processes, but the bases of the processes are very close and it seems like 1 process)
b) True unipolar - 1 process
Epithelial tissue- the outer surface of human skin, as well as the lining surface of the mucous membranes of internal organs, gastrointestinal tract, lungs, most glands.
The epithelium is devoid of blood vessels, so nutrition is provided by the adjacent connective tissues, which are nourished from the bloodstream.
Functions of epithelial tissue
Main function skin epithelial tissue - protective, that is, limiting the impact of external factors on internal organs. Epithelial tissue has a multilayer structure, so keratinized (dead) cells are quickly replaced by new ones. It is known that epithelial tissue has increased regenerative properties, which is why human skin is rapidly renewed.
There is also intestinal epithelial tissue with a single layer structure, which has absorptive properties, due to which digestion occurs. In addition, the intestinal epithelium tends to release chemicals, in particular sulfuric acid.
Human epithelial tissue covers almost all organs from the cornea of the eye to the respiratory and genitourinary system. Some types of epithelial tissue are involved in protein and gas metabolism.
The structure of epithelial tissue
The cells of the unilamellar epithelium are located on the basement membrane and form one layer with it. The cells of the stratified epithelium are formed from several layers and only the lowest layer is the basement membrane.
According to the shape of the structure, epithelial tissue is: cubic, flat, cylindrical, ciliated, transitional, glandular, etc.
Glandular epithelial tissue possesses secretory functions, that is, the ability to allocate a secret. The glandular epithelium is located in the intestine, it makes up the sweat and salivary glands, endocrine glands, etc.
The role of epithelial tissue in the human body
The epithelium plays a barrier role, protecting internal tissues, and also aids in the absorption of nutrients. When hot food is consumed, part of the intestinal epithelium dies off and is completely restored overnight.
Connective tissue
Connective tissue- building matter that unites and fills the entire body.
Connective tissue is present in nature in several states at once: liquid, gel, solid and fibrous.
Accordingly, a distinction is made between blood and lymph, fat and cartilage, bones, ligaments and tendons, as well as various intermediate body fluids. The peculiarity of the connective tissue is that there is much more intercellular substance in it than the cells themselves.
Types of connective tissue
— Cartilaginous, there are three types:
a) Hyaline cartilage;
b) Elastic;
c) Fibrous.
— Bone(consists of forming cells - osteoblast, and destructive ones - osteoclast);
— Fibrous, in turn happens:
a) Loose (creates a scaffold for organs);
b) Formulated dense (forms tendons and ligaments);
c) Unformed dense (the perichondrium and periosteum are built from it).
— Trophic(blood and lymph);
— Specialized:
a) Reticular (tonsils, bone marrow, lymph nodes, kidneys and liver are formed from it);
b) Fat (subcutaneous energy reservoir, heat regulator);
c) Pigment (iris of the eye, nipple halo, circumference of the anus);
d) Intermediate (synovial, cerebrospinal and other auxiliary fluids).
Connective tissue functions
These structural features allow the connective tissue to perform various functions:
- Mechanical(supporting) function is performed by bone and cartilage tissue, as well as fibrous connective tissue of tendons;
- Protective the function is performed by adipose tissue;
- Transport the function is performed by liquid connective tissues: blood and lymph.
Blood provides the transport of oxygen and carbon dioxide, nutrients, metabolic products. Thus, the connective tissue connects the parts of the body to each other.
Connective tissue structure
Most of the connective tissue is the intercellular matrix of collagen and non-collagen proteins.
Besides him - naturally cells, as well as a number of fibrous structures. The most important cells can be called fibroblasts that produce substances of the intercellular fluid (elastin, collagen, etc.).
Basophils (immune function), macrophages (destroyers of pathogens) and melanocytes (responsible for pigmentation) are also important in the structure.
Man is a biological being, the internal structure of which has features that would be useful and cognitive to understand. For example, inside and out, we are covered with different fabrics. And these tissues differ in structure and function, for example, epithelial tissue from connective tissue.
Epithelial tissue (or epithelium) lines the internal organs of our body, cavities and the outer layer (epidermis). Connective tissue is not so important in itself, but rather in conjunction with other building elements, it is present almost everywhere. The epithelium forms surfaces and walls, and connective tissues perform supporting and protective functions. It is interesting that it is the connective tissue that exists in four forms at once: solid (skeleton), liquid (blood), gel-like (cartilaginous formations) and fibrous (ligaments). The connective tissue has a highly saturated intercellular substance, while the epithelial tissue contains almost no intercellular substance.
Epithelial cells are mostly cellular, not elongated, dense. Connective tissue cells are elastic, elongated. As a result of embryonic development, connective tissue is formed from the mesoderm (middle layer, germ layer), and the epithelium from the ectoderm or endoderm (outer or inner layer).
Conclusions site
- Epithelial tissue and connective tissue perform different functions: the first is lining, the second is supporting.
- Connective tissue in the body has a greater variety of forms.
- Connective tissue and epithelium differ in different content of intercellular substance.
- Basically, the epithelial cells are cellular, and the connective cells are elongated.
- The epithelium and connective tissue are formed at different stages of embryogenesis (embryonic development).
Biology lesson in grade 8 Lesson number 6
Lesson topic: Basic human tissues. Epithelial and connective tissue.
The purpose of the lesson: to give a general idea of the variety of tissues in the human body and their functions;
Lesson Objectives:
Educational: to reveal the concept of the tissues of a multicellular animal organism and the classification of tissues.
At the level of the periodontal ligament, there may be some structural changes due to various trauma or forces that can be applied in the occlusal areas. One of these changes may be a ligament rupture, which accompanies hemorrhage, necrosis, destruction or resorption of blood vessels and bone resorption. Thus, in this situation, the tooth significantly loses from the attachment that holds it in the alveoli, and becomes weak. The repair process can take place quickly due to the specific properties of collagen.
Vascularization of the periodontal ligament
The cells that the periodontal ligament adheres to are: fibroblasts, osteoblasts, osteoclasts, cementoblasts, Malassi cell debris, macrophages, cells associated with vascular and neural structures. Blood lightening Provided by the upper and lower alveolar arteries, which flow into the alveolar bone, taking the form of the interalveolar arteries.
Developing: develop the ability to compare the structural features of tissues in connection with the functions performed.
Educational: to foster the spirit of competition, quick thinking, the ability to conduct analysis, to carry out aesthetic education.
Equipment: drawings "Human cell",
Teaching method: verbal, explanatory and illustrative.
Innervation of the periodontal ligament
Functions performed by the periodontal ligament
The structure of the alveolar processes. The actual alveolar bone, also called hard lamellae or crushed stone, is the bony portion of the attachment of the ligament fibers and coincides with the facial bone. The alveolar abutment bone includes both the cancellous and the cortical plate and represents the outer body and the limit of the alveolar process.With age, the loss of teeth leads to the formation of narrow jaws, which leads to a reduction in processes, which ultimately leads to a loss of bone mass. Alveolar processes are extremely sensitive to the transmission of sensations of pressure and tension, which by their nature stimulate the process of bone formation.
Predicted result: students will study the tissues of the human body.
Lesson type: revealing the content of the topic.
Lesson type: combined.
Lesson plan:
1. Organization of the class.
2. Checking homework.
4. Homework.
5. Viewing a fragment of a video
During the classes:
Fasciitis bone. It occurs in the dental follicle and is the point of attachment of fiber bundles in the periodontal ligament. The name of the fascicular bone is associated with Shar-Pei fibers and numerous perforations that lead to the formation of vascular and nerve elements, therefore it is called a crypt-like plate.
Spongy bone Located between the cortical plate and the fascicular bone. It occupies the middle of the alveolar processes and is trabecular in nature. Cortical plate It is located on the surface of the alveolar processes and extends from the alveolar ridge to the lower limits of the alveoli. It is finely fibrillated thin bone, consisting of longitudinal lamellas, Havers canals, which together form Haversian systems of thickness, which vary considerably.
1. Organization of the class:
I come in. Hello. Checking attendance. I report the topic of the lesson and the plan of work for the lesson.
2. Checking homework:
Retelling of the theme “Cell organelles. The chemical composition of the cell "and independent work (Notebook with tasks for individual work, grade 8, part 1, page 6)
3. Learning new material.
Vulcanization of alveolar processes
Functions of alveolar processes
Signs that can occur at the periodontal level. Changes in the contours of the gums, which can occur in the form of: recession, true or false periodontal pockets, fracture lesions. They are caused by swelling and swelling of the mucous membranes of the gums, or a decrease in resin volume.Volume changes in the gingival mucosa. A decrease in volume, which can be physiological or pathological. Physiological due to the aging process, and pathological due to dystrophic forms of periodontopathy. The increase in volume is associated with gingival hyperplasia and hypertrophy.
In the body of humans and animals, individual cells or groups of cells, adapting to the performance of various functions, differentiate, i.e. change their forms and structure accordingly, remaining at the same time interconnected and subordinate to a single integral organism. This process of continuous development of cells leads to the emergence of many different types of cells that make up human tissue.
You know that the human body, like all living organisms, consists of cells. The cells are not randomly arranged. They are connected by the intercellular substance, grouped and form tissues. Tissue is a collection of cells that are identical in origin, structure and functions. Tissues are divided into 4 groups: epithelial, connective, muscular and nervous.
Epithelial tissue (from the Greek epi - surface), or epithelium, forms the top layer of the skin (only a few cells thick), mucous membranes of internal organs (stomach, intestines, excretory organs, nasal cavity), as well as some glands. The cells of the epithelial tissue are closely adjacent to each other. Thus, it performs a protective role and protects the body from the ingress of harmful substances and microbes into it. Cell shapes are various: flat, tetrahedral, cylindrical, etc. The structure of the epithelium can be single-layer and multi-layer. So, the outer layer of the skin is multi-layered. When it peels off, the upper cells die off and are replaced by internal ones, the next.
Depending on the function performed, the epithelium (Fig. 3) is divided into the following groups:
glandular epithelium - cells secrete milk, tears, saliva, sulfur;
the ciliated epithelium of the respiratory tract retains dust and other foreign bodies with the help of mobile cilia. Hence its other name - ciliated;
the stratified integumentary epithelium covers the surface of the skin and the oral cavity, lines the esophagus from the inside; single-layer tetrahedral (cubic) - lining the renal tubules from the inside; cylindrical - lining the inside of the stomach and intestines;
the sensitive epithelium perceives excitement. For example, the olfactory epithelium of the nasal cavity is very sensitive to odors.
Functions of epithelial tissue:
1) protects the tissues underneath;
2) regulates the constancy of the internal environment of the body;
3) participates in the metabolism at the initial and final stages;
4) regulates metabolism, etc.
Connective tissue. Connective tissue is formed by blood, lymph, bones, fat, cartilage, tendons, ligaments. By structure, connective tissue is subdivided into dense fiber, cartilaginous, bone, loose fiber, blood and lymph (Fig. 4).
Dense-fibrous tissue - cells are located close to each other, there is a lot of intercellular substance, a lot of fibers. It is located in the skin, in the walls of blood vessels, ligaments and tendons.
Cartilage tissue - spherical cells, arranged in bundles. There is a lot of cartilage tissue in the joints, between the vertebral bodies. The epiglottis, pharynx and auricle are also made of cartilage.
Bone. It contains calcium salts and protein. Bone connective tissue cells are alive, surrounded by blood vessels and nerves. The structural unit of bone tissue is osteon. It consists of a system of bone plates in the form of cylinders inserted into each other. Between them are bone cells - osteocytes, and in the center - nerves and blood vessels. Skeletal bones are composed entirely of this tissue.
Loose-fiber fabric. Fibers are intertwined with each other, cells are located close to each other. Surrounds blood vessels and nerves, fills the space between organs. Bonds skin to muscles. It forms a loose tissue under the skin - subcutaneous fatty tissue.
Blood and lymph are fluid connective tissue.
Connective tissue functions:
1) gives strength to fabrics (dense fiber fabric);
2) forms the basis of the tendons and skin (dense tissue);
3) performs a supporting function (cartilage and bone tissue);
4) provides transportation of nutrients and oxygen (blood, lymph) throughout the body.
4. Watch the video clip
Disc "Human Anatomy"
5. Homework
(retelling § 7)
6. Lesson summary and grading.
What conclusion did you draw at the end of our lesson?
Tissues are a collection of cells and non-cellular structures (non-cellular substances) that are similar in origin, structure and functions. There are four main groups of tissues: epithelial, muscle, connective and nervous.
... Epithelial tissues cover the body from the outside and line the hollow organs and walls of body cavities from the inside. A special type of epithelial tissue - glandular epithelium - forms most of the glands (thyroid, sweat, liver, etc.).
... Epithelial tissues have the following features: - their cells are closely adjacent to each other, forming a layer; - there is very little intercellular substance; - cells have the ability to recover (regenerate).
... Epithelial cells in shape can be flat, cylindrical, cubic. According to the number of layers of the epithelium, there are single-layer and multi-layer.
… Examples of epithelium: a monolayer flat epithelium lines the chest and abdominal cavities of the body; multi-layered flat forms the outer layer of the skin (epidermis); monolayer cylindrical lines most of the intestinal tract; multilayer cylindrical - the cavity of the upper respiratory tract); monolayer cubic forms the tubules of the nephrons of the kidneys. Functions of epithelial tissues; borderline, protective, secretory, suction.
CONNECTING TISSUE PROPERLY CONNECTING SKELETAL Fibrous Cartilaginous 1. loose 1. hyaline cartilage 2. dense 2. elastic cartilage 3. formed 3. fibrous cartilage 4. unformed With special properties Bone 1. reticular 1. coarse fibrous 2. fatty 2. lamellar: 3. mucous compact substance 4.pigmented spongy substance
… Connective tissues (tissues of the internal environment) unite groups of tissues of mesodermal origin, very different in structure and function. Types of connective tissue: bone, cartilaginous, subcutaneous fatty tissue, ligaments, tendons, blood, lymph, etc.
... Connective tissues A common characteristic feature of the structure of these tissues is a loose arrangement of cells, separated from each other by a well-defined intercellular substance, which is formed by various proteins of a protein nature (collagen, elastic) and the main amorphous substance.
... Blood is a kind of connective tissue, in which the intercellular substance is liquid (plasma), due to which one of the main functions of blood is transport (carries gases, nutrients, hormones, end products of the vital activity of cells, etc.).
... The intercellular substance of loose fibrous connective tissue located in the layers between organs, as well as connecting the skin with muscles, consists of an amorphous substance and elastic fibers freely located in different directions. Due to this structure of the intercellular substance, the skin is mobile. This tissue has a supporting, protective and nourishing function.
... Muscle tissues determine all types of motor processes inside the body, as well as the movement of the body and its parts in space.
... This is due to the special properties of muscle cells - excitability and contractility. All cells of muscle tissue contain the finest contractile filaments - myofibrils, formed by linear protein molecules - actin and myosin. When sliding them relative to each other, the length of the muscle cells changes.
... Transversely striated (skeletal) muscle tissue is built from many multinucleated fiber-like cells 1-12 cm long. All skeletal muscles, muscles of the tongue, walls of the oral cavity, pharynx, larynx, upper part of the esophagus, mimic, diaphragm are built from it. Figure 1. Fibers of striated muscle tissue: a) the appearance of the fibers; b) cross section of fibers
... Peculiarities of striated muscle tissue: speed and volition (ie, dependence of contraction on the will, desire of a person), consumption of large amounts of energy and oxygen, rapid fatigability. Figure 1. Fibers of striated muscle tissue: a) the appearance of the fibers; b) cross section of fibers
... The heart tissue consists of transversely striated mononuclear muscle cells, but has different properties. The cells are not arranged in a parallel bundle, like skeletal cells, but branch, forming a single network. Thanks to the many cell contacts, the incoming nerve impulse is transmitted from one cell to another, providing simultaneous contraction and then relaxation of the heart muscle, which allows it to perform a pumping function.
... Cells of smooth muscle tissue do not have cross striation, they are fusiform, mononuclear, their length is about 0.1 mm. This type of tissue is involved in the formation of the walls of the tubular internal organs and blood vessels (digestive tract, uterus, bladder, blood and lymph vessels).
... Nerve tissue, from which the brain and spinal cord, nerve nodes and plexuses, peripheral nerves are built, performs the functions of perception, processing, storage and transmission of information coming both from the environment and from the organs of the organism itself. The activity of the nervous system ensures the body's reactions to various stimuli, regulation and coordination of the work of all its organs.
... Neuron - consists of a body and processes of two types. The body of a neuron is represented by the nucleus and the surrounding cytoplasm. It is the metabolic center of the nerve cell; when it is destroyed, it dies. The bodies of neurons are located mainly in the brain and spinal cord, that is, in the central nervous system (CNS), where their clusters form the gray matter of the brain. Clusters of nerve cell bodies outside the central nervous system form nerve nodes, or ganglia.
Figure 2. Different shapes of neurons. a - a nerve cell with one process; b - a nerve cell with two processes; c - a nerve cell with a large number of processes. 1 - cell body; 2, 3 - processes. Figure 3. Diagram of the structure of the neuron and nerve fiber 1 - the body of the neuron; 2 - dendrites; 3 - axon; 4 - axon collaterals; 5 - myelin sheath of the nerve fiber; 6 - terminal branching of the nerve fiber. The arrows show the direction of propagation of nerve impulses (according to Polyakov).
… The main properties of nerve cells are excitability and conductivity. Excitability is the ability of the nervous tissue to enter a state of excitement in response to irritation.
... conduction is the ability to transmit excitation in the form of a nerve impulse to another cell (nervous, muscular, glandular). Thanks to these properties of the nervous tissue, perception, conduct and formation of the body's response to the action of external and internal stimuli are carried out.
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