Animal eye fabrics are two main varieties: one is characteristic of many invertebrates, and the other - spinal, such as fish or people. The main difference between them is that the light-graded surface of sensitive increases in different way

Chapter 32. Features of metabolism in the nervous tissue The human brain is the most difficult of all known living structures. The nervous system and, first of all, the brain belongs to the most important role in coordinating behavioral, biochemical, physiological

Energy exchange in the nervous tissue with characteristic features of the energy exchange in brain tissue are: 1. High intensity in comparison with other tissues.2. High speed of oxygen consumption and blood glucose. Head Brain, Share

Lipid exchange in the nervous tissue The lipid composition of the brain is unique not only at a high concentration of common lipids, but also by content here for their individual fractions. Almost all brain lipids are represented by three main fractions: glycelifospholipids,

Chapter 33. Muscle tissue biochemistry Mobility is a characteristic feature of all forms of life - the discrepancy of chromosomes in the mitotic apparatus of cells, air-screw movements of bacteria flavors, bird wings, precise movements of the human hand, powerful work of the leg muscles. Everything

Muscle tissue proteins isolated three groups of proteins: 1. Myofibrillic proteins - 45%; 2. Sarcoplasmatic proteins - 35%; 3. Stromine proteins - 20%. The phibrillary proteins. For this group include: 1. Mozin; 2. Aktin; 3. Actomiosis; as well as the so-called regulatory proteins: 4. Tropomyozine; 5.

Chapter 34. Biochemistry of connective tissue The connecting tissue is about half of the dry mass of the body. All varieties of connective tissue, despite their morphological differences, were built under the general principles: 1. Contains little cells in comparison with other

The main types of animal tissues:
■ epithelial (cover);
■ connecting;
■ muscle;
■ nervous.

Epithelial fabric

Epithelial fabric, or epithelium- view of the coating fabric in animals forming the outer coverings of the body, glands, as well as the lining of the inner walls of the hollow organs of the body.

❖ Epithelial functions:

■ protection of underlying structures from mechanical damage, the effects of harmful substances and infections penetration;

■ participation in the metabolism (ensures suction and selection of substances);

■ participation in gas exchange (many groups of animals breathing through the entire surface of the body);

■ receptor (sensitive epithelium may contain cells with receptors that perceive external irritation, for example, odors);

■ secretory (for example, the mucus highlighted by glass-shaped cells of the cylindrical epithelium of the stomach protects it from the impact of the gastric juice).

The epithelium is formed, as a rule, from ecto- and enantoderma and has a high ability to restore. It forms one or more layers of cells lying on fine basal membrane , deprived of blood vessels. Cells firmly adjacent to each other, forming a solid reservoir; There is almost no intercellular substance. Epithelium power is carried out due to the connective tissue.

Basal membrane - layer of the intercellular substance (proteins and polysaccharides), located on the boundaries between different tissues.

Cell-shaped epithelial classification:

■ flat (consists of polygonal cells, forms a surface layer of skin and lifts the vessels of blood and lymphatic systems, pulmonary alveoli, body cavities);

■ cubic (consists of cubic cells; present in the renal tubules, the retina of the eye of vertebrates, the lumbering of the pancreas and salivary glands, is noted in the outer epithelines of invertebrates);

■ cylindrical , or columnar (its cells have an oblong shape and resemble columns or columns; this epithelium sweeps the intestinal tract of animals, forms the outer epithelium of many invertebrates);

■ ciliary , or ciliary (a type of cylindrical), on the surface of the columnal cells of which there are numerous cilia or single flagellas (wrecks the respiratory tract, eggs, cerebral ventricles, the spinal channel).

Classification of surface epithelium depending on the number of cell layers:

■ single-layer (its cells form only one layer); It is characteristic of invertebrates and lower chord. The vertebrates it sweeps the blood and lymphatic vessels, the heart cavity, the inner surface of the cornea of \u200b\u200bthe eye, etc. (flat epithelium), vascular brain plexus, kidney channels (cubic epithelium), gallbladder, kidney ducts (column epithelium);

■ multi-layered (its cells consist of several layers); It forms the outer surfaces of the skin, some mucous membranes (mouth cavity, a throat, some parts of the esophagus -stuffed and flat epithelium), ducts of salivary and Milky glands, vagina, sweat glands (cubic epithelium), etc.

Epidermis — outer layer skin directly in contact with environmental and consisting of living and dead, thickened, buried and constantly lunning cells, which are replaced by new due to regeneration - cellular division occurring in this tissue very quickly.

■ Human cells of the epidermis are updated every 7-10 days.

Leather - external cover of the body of ground vertebrates (reptiles, birds, mammals), which performs the function of maintaining the constancy of body temperature.

Box and shaped cells - single-cell glands having a characteristic form of a glass, scattered among the epithelial cells of some organs (for example, a mucus secreted by some glass-like cells is necessary for the ground organisms for breathing and drying protection).

Gland - Animal or human body that produces special substances - secrets (milk, sweat, digestive enzymes, etc.), which are involved in metabolism (examples: salivary, sweat, milk, sebaceous glands, inland secretion glands - thyroid, pancreas, etc. ).

Sensitive epithelium - epithelium containing cells that perceive external irritation ( example: The epithelium of the nasal cavity, which has receptors that perceive smells).

Irony epithelium - a special form of epithelial tissue in vertebrates, consisting of clusters of cells forming multicellular iron .

Types of secretory cells of ferrous epithelium:

■ ecocrine cellsForming ecocrine glands (liver, pancreas, glands of the stomach and intestines, salivary glands), distinguish the secret on the free surface of the epithelium through the output ducts of the glands;

■ endocrine cellsForming endocrine glands (thyroid gland, hypophies, adrenal glands, etc.), secrete secrets directly into the intercellular space, penetrated by blood vessels, from where they enter blood and lymph.

Connective tissue

Connecting fabric - the main support fabric of the body, connecting the remaining tissues and organs and forming the inner skeleton of many animals. The connecting fabric is formed from the mesoderm.

Connective tissues:

■ bones, cartilage, ligaments, tendons, dentin (located between the dental enamel and the pulp cavity of the tooth);

■ red bone marrow;

■ blood and lymphs, as well as tissue surrounding blood vessels and nerves in the fields of their entry or exit to one or another;

■ subcutaneous fatty tissue, etc.

❖ Connective fabric functions:
■ reference (main function),
■ Protective (phagocytosis),
■ exchange (transfer of substances by body),
■ Nutrient (trophic),
■ ROOM (red bone marrow),
■ Restorative (regeneration).

❖ Connective fabric features: different types of it have a different structure, but in all cases
■ The fabric has a complex structure;
■ It has a very high recovery ability;
■ It may include a variety of cells (fibroblasts, fibrocytes, fat, fat and pigment cells plasmocytes , lymphocytes, granular leukocytes, macrophages, etc.) located loose, at a considerable distance from each other;

■ well expressed continuous (amorphous) soft intercellular substance separating the cells one from another that may include fiber protein nature ( collagen., Elastic and reticular ), Various acids and sulfates and non-residential products of the vital cells of the cells. Collagen fibers - flexible, especially durable, unsengiving fibers formed from the collagen protein, whose molecular chains have a spiral structure and can be twisted and combined with each other; Easily resistant temperature denaturation.

Elastic fibers - fibers formed mainly protein elastin capable of stretching about 1.5 times (after which they are returned to the original state) and perform the reference function. Elastic fibers are intertwined with each other, forming networks and membranes.

Reticular fibers - These are thin, branched, corrosion-high, intertwined fibers, forming a small-scale network, in the cells of which cells are located. These fibers form the framework of the blood formation organs and the immune system, liver, pancreas and some other organs, surround the blood and lymphatic vessels, etc.

Fibroblasts - Main specialized fixed cells of connective tissue, synthesizing and secreting the main components of the intercellular substance, as well as substances from which collagen and elastic fibers are formed.

Fibrocytes - multiple spindle-shaped cells, in which, as fibroblasts turn into; Fibrocytes synthesize the intercellular substance is very weak, but form a three-dimensional network in which other cells are held.

Fat cells - These are cells, very rich in large (up to 2 μm) granules containing biologically active substances.

Reticular cells - Extended manproof cells, which, connecting with their processes, form a network. Under adverse conditions (infection, etc.), they are rounded and become capable of phagocytosis (capture and absorption of large particles).

Fat cells There are two types - white and brown. White fat cells have a spherical shape and almost completely filled with fat; They carry out the synthesis and intracellular accumulation of lipids as a spare substance. Brown fat cells contain drops of fat and a large amount of mitochondria.

Plasmocytes - cells, synthesizing proteins and located near small blood vessels in the organs of the immune system, in the mucous membrane of the digestive and respiratory systems. They produce antibodies And thereby playing an essential role in the protection of the body.

Classification of connective tissues Depending on the composition of cells, such as the properties of the intercellular substance and the associated functions in the body: loose fibrous connective tissue, dense fibrous, cartilage and bone connecting fabrics and blood.

Loose fibrous connecting fabric - very flexible and elastic tissue, consisting of rarely located cells of different types (many variable shape cells), intertwined reticular or collagen fibers and liquid intercellular substances, filling gaps between cells and fibers. Forms stroma - framework of organs and an outer shell of internal organs; It is placed in layers between the organs, connects the skin with the muscles and performs the protective, stocking and nourishing functions.

Dense fibrous connecting tissue consists mainly of beams of collagen fibers located tightly and parallel to each other or intertwined in different directions; free cells and amorphous substances are a bit. The main function of dense fibrous connective tissue is reference. This fabric forms bundles, tendons, periosteum, deep layers of skin (dermis) of animals and man, lifts from the inside the skull and vertebral channel, etc.

Cartilage fabric - This is an elastic fabric consisting of round or oval cells ( chondrocyte) lying in capsules (from one to four pieces in each capsule) and immersed in well developed, dense, but elastic main intercellular substance containing thin fibers. The cartilage tissue covers the articular surfaces of the bones, forms a cartilaginous part of the ribs, a nose, ear shell, larynx, trachea, bronchi and intervertebral discs (in the latter it plays the role of a shock absorber).

Functions of cartilage fabric - Mechanical and connective.

Depending on the amount of the intercellular substance and the type of prevailing fibers allocate hyaline, elastic and fibrous cartilage.

IN guialin Khryashche (It is the most common; shifts the artic heads and depressions of the joints) cells are arranged by groups, the main substance is well developed, collagen fibers prevail.

IN elastic chance (forms the elastic sink) elastic fibers prevail.

Fiber cartilage (located in intervertebral discs) contains little cells and the main intercellular substance; It is dominated by collagen fibers.

Bone It is formed from embryonic connective tissue or from cartilage and is distinguished by the fact that inorganic substances (calcium salts, etc.) are laid in its intercellular substance (calcium salts, etc.), giving fabrics hardness and fragility. It is characteristic of vertebrates and the person who has bones.

Main functions of bone tissue - reference and protective; This fabric also participates in the exchange of minerals and in blood formation (red bone marrow).

Types of bone cells: osteoblasts, osteocytes and osteoclasts (Participate in resorption of old osteocytes).

Osteoblasts - Polygonal processful young cells rich in elements of a grainy endoplasmic network, developed by the complex of Golgji and others. Osteoblasts synthesize the organic components of the intercellular substance (matrix).

Osteocytes - Mature, multi-process spindle-shaped cells with a large core and low organelle. Do not share; In the event of the need for structural changes in the bones, they are activated, differentiated and transformed into osteoblasts.

The structure of bone tissue.

Bone cells are combined with cellular processions. Tight main intercellular substance This tissue contains crystals of calcium salts of phosphoric and coal acids, ions of nitrates and carbonates, giving tissue hardness and fragility, as well as collagen fibers and protein-polysaccharide complexes that give tissue elasticity and elasticity (30% bone tissue consists of organic compounds and 70 % - from inorganic: calcium (bone tissue - depot of this element), phosphorus, magnesium, etc.). In bone tissue there are Gaverca channels -Trub cavities in which blood vessels and nerves pass.

Fully formed bone tissue consists of bone plateshaving different thickness. In a separate plate, collagen fibers are located in one direction, but in adjacent plates they are located at an angle to each other, which gives the bone additional strength.

Depending on the location of the bone plates distinguish compact and sponge bone substance .

IN compact substance Bone plates are located concentric circles near the Gavers channels, forming osteon. Between osteonov are located insert plates .

Spongy The substance consists of thin, crosses the bone plates and the crossbar forming a plurality of cells. The direction of the crossbar coincides with the lines of the main stresses, so they form vaulted structures.

All bones are covered with a dense connective tissue - perceivers providing food and rising bones in thickness.

Fat fabric Educated by fat cells (Read more above) and performs a trophic (nutrient), forming, stocking and thermostatic functions. Depending on the type of fat cells, it is divided into white (performs mainly stocking function) and buru (Its main function - heat production to maintain the temperature of the animal body during hibernation and temperature of newborn mammals).

Reticular connecting fabric - a type of connective tissue forming, in particular, red bone marrow - the main place of blood formation - and the lymph nodes .

Muscle

Muscle - a fabric that makes up the main mass of animal muscles and a person and performing a motor function. Characterized by ability to reduce (under the action of various stimuli) and subsequent length recovery; It is part of the musculoskeletal system, the walls of hollow internal organs, vessels.

❖ Muscle fabric features:
■ It consists of individual muscular fibers and has properties:
■ excitability (able to perceive irritation and respond to them);
■ society (Fibers can short and lengthen),
■ conduction (capable of excitation);
■ Separate muscle fibers, bundles and muscles are weaving with a cunning tissue, in which blood vessels and nerves pass. Muscle color depends on the number of protein present in them. mioglobin .

Muscular fiber formed with the finest contracting fibers - myofibrils, each of which is a regular filament system of proteins molecules mozin (thicker) and aktin (thinner). Muscle fiber is covered with an excitable plasma membrane, according to its electrical properties similar to the membrane of nerve cells.

Energy sources for muscular cuts: ATP (main), as well as creatine phosphate or arginine phosphate (with an energetic muscular reduction), carbohydrate stocks in the form of glycogen and fatty acid (with intensive muscular work).

Types of muscle tissue:

■ transverse (skeletal) ; forms skeletal muscles, muscles of mouth, language, pharynx, top of the esophagus, larynx, diaphragms, facial muscles;

■ cardual ; forms the main mass of the tissue of the heart;

■ smooth ; In the lower animals, forms almost the whole mass of their muscles, the vertebrates are part of the walls of vessels and hollow internal organs.

Skeletal (transverse) muscles - Muscles attached to the skeleton bones and ensuring the movement of the body and limbs). Consist of beams formed by a set of long (1-40 mm or more) multi-core muscle fibers with a diameter of 0.01-0.1 mm, having transverse aperture (which is determined by regular MIO-fibrils regularly relative to each other).

Features of the transverse muscle tissue:

■ It is innervated by spinal nerves (through the central nervous system),

■ Capable to rapid and strong abbreviations,

■ But in it quickly develops fatigue, and a lot of energy is worried for its work.

Heart muscle Forms the bulk of the tissue of the heart and consists of transversely allocated myofibrils, but differs from the skeletal muscle structure: it is not parallel with a parallel bunch, but branched, and the adjacent fibers are connected to each other to the end, as a result of which all the fibers of the heart muscle form a single network . Each fiber of the heart muscle is concluded in a separate membrane, and there are many special slot contacts (brilliant strips) between the fibers connected by its ends, allowing nerve pulses to come from one fiber to another.

Features of cardiac muscular fabric:
■ its cells contain a large number of mitochondria;
■ She has automate : able to generate contractual impulses without the participation of the central nervous system;
■ is reduced involuntary and quickly;
■ has low fatigue;
■ Reduction or relaxation of the heart muscle on one site quickly spreads throughout muscular weight, providing the simultaneity of the process;

Smooth muscular fabric - A variety of muscle tissue, characterized by a slow reduction and slow relaxation and formed by cells of the spindle-shaped form (sometimes branched) with a length of about 0.1 mm, with one nucleus in the center, in the cytoplasm of which are isolated myofibrils. In the smooth muscular tissue there are all three types of contractile proteins - Aktin, Miosin and Tropomyozin. Smooth muscles are devoid of transverse allocations, as they have no ordered arrangement of the filaments of actin and myozin.

Features of smooth muscle tissue:
■ It is innervated in vegetative nervous system;
■ Reduced involuntary, slowly (reduction time - from a few seconds to several minutes), with a small force;
■ can remain in abbreviated state long;
■ Slowly tires.

At the lower (invertebrate) animals, the smooth muscular fabric forms the whole mass of their muscles (the exception is the motor muscles of arthropods, some mollusks, etc.). The vertebrate smooth muscles form muscle layers of internal organs (digestive tract, blood vessels, respiratory tract, uterus, bladder, etc.). Smooth muscles is innervated by a vegetative nervous system.

Nervous fabric

Nervous fabric - animal and human tissue, consisting of nerve cells - neurons (the main functional elements of the tissue) - and the cells between them neuroglia (auxiliary cells performing nutrient, reference and protective function). Nervous fabric forms nervous nodes, nerves, head and spinal cord.

❖ Basic properties of nervous tissue:
■ excitability (she is able to perceive irritation and respond to them);
■ conductivity (Care of excitement).

Functions of nervous tissue - receptor and conductive: perception, processing, storage and transmission of information coming from both the environment and inside the body.

❖ Neuron is a nervous cell, the main structural and functional unit of nervous tissue; It is formed from Etoderma.

The structure of the neuron. Neuron consists of body star or belt-shaped shape with one core, several short branching processes - dendritis - and one long process - axon . The body of the neuron and his processes permeates a thick network of thin threads - neurofibrilli; In his body there are also accumulations of a special substance, rich RNA. Among themselves various neurons are associated with intercellular contacts - synapses .

Bodies of neurons form nerve nodes - ganglia - And nervous centers gray substance Head and spinal cord, neurons processes form nerve fibers, nerves and white substance brain.

The main function of neurona - Getting, processing and transmitting excitation (ie, information encoded in the form of electrical or chemical signals) to other neurons or cells of other tissues. Neuron is able to skip the excitation only in one direction - from the dendrite to the body of the cell.

■ Neurons have secretory activity: can allocate mediators and hormones .

❖ Classification of neurons depending on their functions:

■ sensitive, or afferent, neurons transmit excitation caused by external irritation, from the peripheral bodies of the body to nervous centers;

■ motors, or efferent, neurons transmit motor or secretory impulses from nerve centers to body organs;

■ insert, or mixed, neurons communicate between sensitive and motor neurons; They process information received from sense of sensitive nerves, switch the excitation pulse to the desired motor neuron and transmit relevant information to the highest parts of the nervous system.

Classification of neurons By number of processes: unipolar (Ganglia invertebrates), bipolar , pseudoNIPolar and multipolar .

Dendriti. - Short, strongly branched neurons processes that ensure perception and carrying out nerve pulses to the body of neuron. Do not have a myelin shell and synaptic bubbles.

Akson - A long-thinning neuron's long-term neuron proceedings, along which the excitation is transmitted from this neuron to other neurons or cells of other tissues. Axons can be combined into thin beams, and those in turn - in a thicker bundle, baked by a sheath. - nerve.

Sinaps.- Specialized contact between nervous cells or nerve cells and cells of innervated tissues and organs through which the nervous impulse is transmitted. Formed by two membranes with a narrow slit between them. One membrane belongs to the nervous cell, sending a signal, the other membrane is a cell receiving a signal. The transfer of the nervous pulse occurs with chemical substances - mediators synthesized in the transmitting nervous cell when an electrical signal is received.

Mediator - Physiologically active substance (acetylcholine, norepinephrine, etc.), synthesized in neurons accumulated in special bubbles of synapses and ensuring excitation transmission through synaps from one neuron to another or on the cell of another tissue. It is released by exocytosis from the end of the axon of an excited (transmitting) nervous cell, changes the permeability of the plasma membrane of the receiving nervous cell and causes the appearance of the excitation potential on it.

Glianal cells (neuroglia) - Nervous tissue cells that are not capable of excitation in the form of nervous pulses that serve to transfer substances from blood to nerve cells and back (nutritional function) forming myeline shells, as well as performing support, protective, secretory and other functions. Frame from Mesoderm. Can share.

Ganglion - A group of nerve cells (neurons), carrying out the processing and integration of nerve impulses.

Blood, fabric liquid and lymph and their features of a person

Blood - one of the types of connective tissue; circulates in a circulatory system; consists of a liquid medium - plasma (55-60% of the volume) - and cells weighted in it - forming elements blood ( erythrocytes, leukocytes, thrombocytees ).

■ Composition and amount of blood in different organisms are different. In humans, blood is about 8% of the total body weight (with a mass of 80 kg, blood volume is about 6.5 liters).

■ Most of the blood existing in the body circulates in the body, its remaining part is in the depot (lungs, liver, etc.) and replenishes the blood flow during intensive muscular work and during blood loss.

■ Blood is the basis for the formation of other liquids of the inner environment of the body (intercellular fluid and lymph).

❖ Basic blood functions:

■ respiratory (the transfer of oxygen from the respiratory organs to other organs and tissues of the body and the transfer of carbon dioxide from tissues to the respiratory organs);

■ nutrient (nutrient transfer from the digestive system to tissues);

■ excretory (transfer of substance metabolic products from tissues to the allocation organs);

■ Protective (capture and digestion of alien for the body of particles and microorganisms, the formation of antibodies, the ability to coagulate when bleeding);

■ regulatory (transfer of hormones from the internal secretion gland to tissues);

■ thermostat (by regulating blood current through leather capillaries; based on high heat capacity and thermal conductivity of blood);

■ Homeostatic (participates in maintaining the constancy of the inner environment of the body).

Plasma - a pale yellow liquid, consisting of water and dissolved and weighted substances (in the plasma of a person about 90% water, 9% proteins and 0.87% mineral salts, etc.); Carries out transfer various substances and cells in the body. In particular, it transfers about 90% carbon dioxide in the form of carbonate compounds.

Basic plasma components:
■ Proteins fibrinogen and Protrombin necessary to ensure normal blood coagulation;
■ Belsk albumen gives blood viscosity and connects the calcium present in it;
■ α — globulin Ties thyroxine and bilirubin;
■ β — globulin Binds iron, cholesterol and vitamins A, D and K;
■ γ — globulins (called antibodies) Bind the antigens and play an important role in the immunological reactions of the body. Plasma suffers about 90% carbon dioxide in the form of carbonate compounds.

Serum - This is a plasma without fibrinogen (not coagulated).

❖ Erythrocytes - Red blood cells for vertebrates and some invertebrate animals (needle-boring) containing hemoglobin and enzyme carboangendrase and participating in the transport of oxygen and carbon dioxide according to the body and maintain blood pH level by hemoglobin buffer; Determine the color of the blood.

The number of erythrocytes in one cubic millimeter of blood in a person is about 4.5 million (in women) and 5 million (in men) and depends on the age and health of health; In total, the blood of a person has an average of 23 trillion, erythrocytes.

❖ Features of the structure of red blood cells:
■ in humans they have the shape of two-screwed disks with a diameter of about 7-8 microns (slightly less than the diameter of the narrowest capillaries);
■ their cells do not have the kernel '
■ The membrane of cells is elastic and easily deformed;
■ Cells contain hemoglobin - specific protein associated with an iron atom.

Education of red blood cells: Erythrocytes are formed in the red bone of the plane bones of the sternum, skulls, ribs, vertebrae, clavicle and blades, heads of long tubular bones; The embryo has not yet formed bones, the erythrocytes are formed in the liver and spleen. The rate of formation and destruction of red blood cells in the body is usually the same and constant (in humans - about 115 million cells per minute), but under conditions of low oxygen content, the rate of formation of erythrocytes increases (the mechanism for adapting mammals to a reduced oxygen content in highlands is founded.

Erythrocyte destruction: Erythrocytes are destroyed in the liver or spleen; Their protein components are cleaved by amino acids, and the incoming hem iron is held by the liver, it is stored in it in the composition of ferritin protein and can be used in the formation of new erythrocytes and with cytochrome synthesis. The rest of the hemoglobin is cleaved with the formation of bilirubin and biliveridine pigments, which together with bile are discovered in the intestine and give coloring the mass masses.

Hemoglobin - respiratory pigment contained in the blood of some animals and man; It is a complex of complex proteins and heme (non-protein component of hemoglobin), which includes iron. The main function is the transfer of oxygen by the body. In areas with a high concentration of 2 (for example, in the lungs in terrestrial animals or in fish gowns), hemoglobin binds to oxygen (turning into oxymemoglobin) and gives it in areas with low concentration of 2 (in tissues).

Carboangeeza - an enzyme providing carbon dioxide in a circular system.

Anemia (or anemia) - The condition of the body, in which the number of erythrocytes in the blood is reduced or the content of hemoglobin in them is reduced, which leads to oxygen deficiency and, as a result, to reduce the intensity of ATP synthesis.

Leukocytes, or white blood cells- colorless blood cells capable of exciting (phagocytosis) and digesting foreign proteins, particles and pathogenic microorganisms, as well as the formation of antibodies. Play an important role in the protection of the body from diseases, ensure the development of immunity.

❖ Features of the structure of leukocytes:
■ in size exceeding red blood cells;
■ Do not have a permanent form;
■ cells have a kernel;
■ are capable of division;
■ Capable to independent amoboid movement.

Leukocytes are formed in red bone marrow, thymus, lymph nodes, spleen; The duration of their life is several days (in some types of leukocytes - several years); Credited in the spleen, foci of inflammation.

Leukocytes can pass through small holes in the walls of the capillaries; Detected both in blood and in the intercellular fabric space. In 1 mm 3 of the blood of a person there are approximately 8,000 leukocytes, but this number varies greatly depending on the state of the body.

❖ The main types of human leukocytes: grainy (granulocytes) and invalid (agranulocytes).

❖ Granular leukocytes, or granulocytesThe red bone marrow is formed and contain characteristic granules (grains) and kernels in the cytoplasm, divided into shares that are associated with each other in pairwise or three thin jumpers. The main function of granulocytes is the struggle in the body penetrated by alien microorganisms.

A sign, distinguishing the blood of a woman from the blood of a man: In the blood granulocytes of women from one of the kernel, an outflow having a shape of a drumstand is departed.

■ Granulocyte forms (Depending on the staining of the granules of the cytoplasm with certain dyes): neutrophils, eosinophils, basophiles (all called microphams).

Neutrophila Capture and digesting bacteria; they constitute about 70% of the total number of leukocytes; Their granules are painted main (blue) and sour (red) dyes in purple color.

Eosinophila Effectively absorb complexes antigen - antibody b; They usually make up about 1.5% of all leukocytes, but with allergic conditions, their amount increases sharply; When processing with sour dye eosin, their granules are painted in red.

Basophiles produce heparin (blood coagulation system inhibitor) and histamine (hormone, regulating the tone of smooth muscles and the release of gastric juice); About 0.5% of all leukocytes are accounted for; The main dyes (type of methylene blue) their granules are painted in blue.

❖ Invalid leukocytes, or agranulocytes, contain a large rounded or oval core, which can occupy almost the entire cell, and the endless cytoplasm.

■ Agranulocyte forms: monocytes. and lymphocytes .

Monocytes (macrophages) - The largest leukocytes that can migrate through the walls of the capillaries into the foci of inflammation in the tissues, where they actively phagocyt bacteria and other large particles. Normally, their number in human blood is about 3-11% of the total number of leukocytes and increases in certain diseases.

Lymphocytes - the smallest of leukocytes (a little larger erythrocytes); have a rounded form and contain very little cytoplasm; Able to produce antibodies in response to entering the body of a foreign protein, participate in the development of immunity. Are formed in lymph nodes, red bone marrow, spleen; account for about 24% of the total number of leukocytes; May live more than ten years.

Leukemia - The disease in which the uncontrolled formation of pathologically changed leukocytes begins in the red bone marrow, the content of which in 1 mm 3 of blood can reach 500 thousand and more.

❖ Plates (blood plates) - these are uniform elements of blood, which are cells or fragments of non-control cells and containing substances involved in blood coagulation . They are formed in a red bone marrow from large cells - megakaryocytes. In 1 mm 3 blood is approximately 250 thousand platelets. Credited in the spleen.

Features of the platelet structure:
■ the dimensions are approximately the same as in the erythrocytes;
■ have a rounded, oval or irregular form;
■ Cells do not have the kernel;
■ Surrounded by membranes.

❖ Blood coagulation is a chain process of stopping bleeding by enzymatic formation of fibrin thrombos, in which all blood cells (especially platelets) are involved, some plasma proteins, Ca 2+ ions, wall of the vessel and the surrounding vessel fabric.

❖ Blood coagulation steps:

■ When tissue break, vessel walls, etc. are destroyed thrombocytes, Eased enzyme thromboplastin which initiates blood coagulation process;

■ Under the influence of Ca 2+ ions, vitamin C and some components of blood plasma, thromboplastin turns an inactive enzyme (protein) prothrombin in active thrombin;

■ Thrombin with the participation of Ca 2+ ions initiates the conversion of fibrinogen into the finest threads of the insoluble protein of fibrin;

■ Fibrin forming spongy mass, in the pores of which shape blood elements (erythrocytes, leukocytes, etc.) are stuck (erythrocytes, leukocytes, etc.), forming blood clot - thrombus. Trombus tightly clogs the hole in the vessel, stopping the bleeding.

❖ Blood features of some animal groups

■ in blood ring worms Hemoglobin is present in dissolved form, in addition, colorless amoeboid cells performing protective function circulate in it.

■ W. clavistonogich blood ( hemolyimfa ) Colonless, does not contain hemoglobin, has colorless amoeboid leukocytes and serves to transport nutrients and metabolic products to be excreted. In the blood of crabs, lobsters and some mollusks instead of hemoglobin there is a blue-green pigment hemocianincontaining copper instead of iron.

■ Fish, amphibians, reptiles and birds There are erythrocytes in the blood that contain hemoglobin and (in contrast to human erythrocytes) have a kernel.

❖ Fabric (intercellular) liquid - one of the components of the internal environment of the body; It is surrounded by all the cells of the body, according to the composition is similar to the plasma, but almost contains proteins.

It is formed as a result of leakage of blood plasma through the walls of the capillaries. Provides cells with nutrients, oxygen, hormones, etc. and removes the end products of cell metabolism.

A significant part of the tissue fluid is returned back to the bloodstray by diffusion, or directly into the venous ends of the capillary network, or (most) into closed from one end lymphatic capillaries, forming lymph.

❖ Lymph - one of the types of connective tissue; Colorless or milk-white liquid in the organism of vertebrate animals, close in composition to the blood plasma, but with a smaller (3-4 times) amount of proteins and a large amount of lymphocytes, circulating in lymphatic vessels and formed from tissue fluid.

■ Performs transport (transport proteins, water and fabric salts to blood) and protective functions.

■ The volume of lymph in the human body is 1-2 liters.

Hemolyimfa - colorless or weakly colored liquid circulating in vessels or intercellular cavities of many invertebrate animals with an impaired blood circuit system (arthropod, mollusks, etc.). It often contains respiratory pigments (hemocyanin, hemoglobin), cell elements (amethocytes, excretory cells, less often erythrocytes) and (in a number of insects: ladybugs, some grasshoppers, etc.) potent poisons that cause their failure to predators. Provides transport of gases, nutrients, products.

Hemocianin - Copper-containing respiratory pigment of blue, contained in the hemolymph of some invertebrate animals and providing oxygen transfer.

The combination of cells and the intercellular substance similar by origin, structure and performed functions are called cloth. In the human body allocate 4 main groups of tissues: Epithelial, coupling, muscular, nervous.

Epithelial fabric (Epithelium) forms a layer of cells, of which the cover of the body and the mucous membranes of all internal organs and cavities of the body and some glands are consisting. Through the epithelial fabric, the metabolism between the organism and the environment. In the epithelial tissue, the cells are very close to each other, the intercellular substance is not enough.

Thus, an obstacle is created for penetration of microbes, harmful substances and reliable protection of the fabrics lying under the epithelium. Due to the fact that the epithelium is constantly subjected to a variety of external influences, its cells die in large quantities and are replaced by new ones. Cell change due to the ability of epithelial cells and rapidly.

There are several types of epithelium - skin, intestinal, respiratory.

The derivative of the skin epithelium includes nails and hair. Intestinal epithelium monosight. It forms and glands. This is, for example, pancreas, liver, salivary, sweat glands, etc. The enzymes separated by the glands split the nutrients. Nutrient cleavage products are absorbed by intestinal epithelium and fall into blood vessels. The respiratory tract is lined with fiscal epithelium. His cells have a facing dust of mobile cilia. With their help, solid particles with air are removed from the organism.

Connective tissue. The feature of the connective tissue is the strong development of the intercellular substance.

The main functions of the connective tissue are nutritious and reference. The connective tissue includes blood, lymph, cartilage, bone, adipose tissue. Blood and lymph consist of a liquid intercellular substance and floating blood cells in it. These fabrics provide communication between organisms, carrying various gases and substances. The fibrous and connecting tissue consists of cells associated with each other in the form of fibers. Fibers can lie tightly and loose. Fibrous connecting fabric is available in all organs. On loosely, well-fat fabric. It is rich in cells that are filled with fat.

IN cartilage fabric Cells are large, the intercellular substance is elastic, dense, contains elastic and other fibers. The cartilage tissue is much in the joints, between the bodies of the vertebrae.

Bone It consists of bone plates inside which the cells lie. Cells are connected to each other with numerous subtle processes. Bone tissue is characterized by hardness.

Muscle. This fabric is formed by muscle. In their cytoplasm there are the finest threads capable of reduction. Eliminate smooth and cross-striped muscle tissue.

The cross-striped fabric is called because its fibers have a cross-term allocated, representing alternation of light and dark areas. Smooth muscular fabric is part of the walls of the internal organs (stomach, guts, bladder, blood vessels). The transverse-striped muscle tissue is divided into skeletal and heart. Skeletal muscle tissue consists of fibers of an elongated form reaching a length of 10-12 cm. Heart muscular fabric, as well as skeletal, has a cross-term allocated. However, unlike skeletal muscle, there are special sections here, where muscle fibers are tightly closed. Due to this structure, the reduction of one fiber is rapidly transmitted to the neighboring. This ensures the simultaneity of the reduction of large sections of the heart muscle. Absolition of muscles is of great importance. The reduction of skeletal muscles ensures the movement of the body in the space and the movement of some parts relative to the other. Due to the smooth muscles, there is a reduction in the internal organs and the change in the diameter of blood vessels.

Nervous fabric. The structural unit of the nervous tissue is the nervous cell - neuron.

Neuron consists of body and processes. The body of the neuron can be different shapes - oval, star, polygonal. Neuron has one core, usually in the center of the cell. Most neurons have short, thick, highly branched processes and long (up to 1.5 m), and thin, and branching only at the very end of the process. Long nerve cell processes form nerve fibers. The main properties of the neuron is the ability to be excited and the ability to carry out this excitation by nerve fibers. In the nervous tissue, these properties are especially well expressed, although characteristic of the muscles and glands are also characteristic. The excitation aroused over neuron and can be transmitted to the other neurons or muscle associated with it, causing its abbreviation. The value of the nervous tissue forming the nervous system is huge. Nervous fabric is not only part of the organism as part of it, but also provides combining functions of all other parts of the body.

The body of many living organisms consists of tissues. Exceptions are all unicellular, as well as some multicellular, for example, which include algae, as well as lichens. In this article we will look at the types of fabrics. Biology studies this topic, namely its section - histology. The name of this industry comes from the Greek words "fabric" and "knowledge." There are very many types of fabrics. Biology studies vegetable, and animals. They have significant differences. Biology is studied for quite a long time. For the first time they were described by even ancient scientists as Aristotle and Avicenna. Fabrics, types of fabrics Biology continues to study and further - in the XIX century they investigated such well-known scientists as Moldenhauer, Mirbel, Garthig and others. With their participation, new types of cell aggregates were opened, their functions were studied.

Types of fabrics - biology

First of all, it should be noted that the fabrics that are characteristic of plants are not characteristic of animals. Therefore, the types of fabrics biology can divide into two large groups: vegetable and animals. Both unite a large number of varieties. We are next and consider them.

Types of animal fabrics

Let's start with what closer to us. Since we treat the kingdom of animals, our body consists precisely from tissues whose varieties will now be described. Types of animal fabrics can be combined into four large groups: epithelial, muscular, coupling and nervous. The first three are divided into many varieties. Only the last group is represented only by one type. Next, consider all types of fabrics, the structure and functions that they are characteristic, in order.

Nervous fabric

Since it happens only one variety, let's start with her. Cells of this tissue are called neurons. Each of them consists of body, axon and dendrites. The latter is the processes for which electric impulse Transmitted from the cell to the cell. Akson at Neuron is one - this is a long process, dendrites are several, they are smaller than the first. In the body of the cell is the kernel. In addition, in the cytoplasm there are so-called Nissle Taurus - an analogue of the endoplasmic reticulum, mitochondria, which produce energy, as well as neurotubule, which are involved in the pulse from one cell to another.

Depending on its functions, neurons are divided into several types. The first type is sensory, or afferent. They spend the impulse from the senses to the brain. The second type of neurons is associative, or switchable. They analyze the information that came from the senses, and produce a response impulse. These types of neurons are in the head and spinal cord. Last variety - motor, or afferent. They carry out impulse from associative neurons to the authorities. Also in the nervous tissue there is an intercellular substance. It performs very important functions, namely, it provides a fixed arrangement of neurons in space, participates in the removal of unnecessary substances from the cell.

Epithelial

These are such types of fabrics whose cells are firmly adjacent to each other. They can have a variety of shape, but always located close. Everything different kinds Tissues of this group are similar to and in the fact that there are few intercellular substances. It is mainly represented in the form of a fluid, in some cases it may not be. These are the types of body fabrics that provide its protection, and also perform a secretory function.

This group combines several varieties. It is flat, cylindrical, cubic, touch, seating and ironed epithelium. From the name of everyone you can understand, from the cells of which form they consist. Different types of epithelial tissues are different and their location in the body. So, the flat lins the cavity of the upper organs of the digestive tract - the oral cavity and esophagus. Cylindrical epithelium is in the stomach and intestines. Cubic can be found in the renal tubules. The sensor lifts the nasal cavity, there are special villi on it, providing perception of smells. Cells of the family epithelium, as clear from its name, have cytoplasmic cilia. This type of fabric sweeps the respiratory tracts that are below the nasal cavity. Cilia, which have each cell, perform a cleaning function - to some extent filtered the air, which passes through the organs covered with this type of epithelium. And the last variety of this group of tissues is a glanded epithelium. Its cells perform a secretory function. They are in the glands, as well as in the cavity of some organs, such as the stomach. Cells of this type of epithelium produce hormones, gastric juice, milk, skin fat and many other substances.

Muscular fabrics

This group is divided into three types. The muscle is smooth, cross-striped and heartfelt. All muscle tissues are similar to the fact that consist of long cells - fibers, they contain a very large amount of mitochondria, since they need a lot of energy to carry out movements. Will out the cavity of the internal organs. With the reduction of such muscles, we cannot control themselves, since they are innervated by the autonomous nervous system.

Cross-striped muscle tissue cells are characterized in that they contain more mitochondria than in the first. This is explained by the fact that they need more energy. The transverse and striped muscles can decline much faster than smooth. It consists of skeletal muscles. They are innervated by the somatic nervous system, so we can consciously control them. Muscular heart fabric combines some of the first two characteristics. It is also able to actively and quickly shrink, as a cross-striped, but is innervated by the autonomous nervous system, as well as smooth.

Connecting types of fabrics and their functions

All tissues of this group are characterized by a large number of intercellular substance. In some cases, it acts in a liquid aggregate state, in some - in liquid, sometimes - in the form of an amorphous mass. This group belongs to seven types. It is dense and loose fibrous, bone, cartilage, reticular, fat, blood. In the first variety the fibers are dominated. It is located around the internal organs. Its functions are to give them elasticity and their protection. In loose fiber tissue, the amorphous mass prevails over the fibers themselves. It completely fills the gaps between the internal organs, while the dense fibrous forms only peculiar shells around the latter. She also plays a protective role.

Bone and form a skeleton. It performs the reference function in the body and partly protective. In the cells and intercellular substance of bone tissue, it is mainly the phosphates and calcium compounds. The exchange of these substances between the skeleton and blood regulates such hormones as calcitonin and paratyrotropin. The first maintains the normal state of the bones, participating in the conversion of phosphorus and calcium ions in organic compounds, inserted in the skeleton. And the second, on the contrary, with the lack of these ions in the blood, it provokes to obtain them from the tissues of the skeleton.

Blood contains a lot of liquid intercellular substance, it is called plasma. Her cells are pretty dear. They are divided into three types: platelets, erythrocytes and leukocytes. The first are responsible for blood coagulation. During this process, a small thrombus is formed, which prevents further blood loss. Erythrocytes are responsible for the transport of oxygen in the body and providing them with all tissues and organs. They may contain agglutinogens that exist two species - A and V. In blood plasma, the content of alpha or beta agluutinins is possible. They are antibodies to agleteine. For these substances, the blood type is determined. The first group on red blood cells does not observe agglutinogen, and there are two species in the plasma at once. The second group has agglutinogen a and agluutinine beta. Third - B and Alpha. In plasma, there are no agluutinins in the plasma, but on the erythrocytes there are agglutinogens and A, and V. If A is found with alpha or in a beta, the so-called agglutination reaction occurs, as a result of which red blood cells die and thrombus are dying. This can occur if the blood is in opposed by the group. Given that only erythrocytes are used when overflowing (plasma is filled at one of the stages of processing donor blood), then only the blood of its group can be overflowed with the first group, from the second - the first and second group, from the third - the first and third group, From the fourth - any group.

Also on erythrocytes can be antigens D, which determines the Rh factor if they are present, the latter is positive, if there is no negative. Lymphocytes are responsible for immunity. They are divided into two main groups: in lymphocytes and T-lymphocytes. The first are produced in the bone marrow, the second - in the thymus (iron located behind the sternum). T-lymphocytes are divided into T-inductors, T-helpers and T-suppressors. The reticular connecting tissue consists of a large amount of intertoral substance and stem cells. Of these, blood cells are formed. This fabric is the basis of the bone marrow and other blood formation organs. There is also cells of which contain lipids. It performs a spare, heat insulating and sometimes protective function.

How are plants arranged?

These organisms, as well as animals, consist of sets of cells and an intercellular substance. Types of plant fabrics We describe further. All of them are divided into several large groups. These are educational, coating, conductive, mechanical and basic. Types of plant tissues are numerous, since each group owns several.

Educational

These include the top, side, insert and wound. Their main function is to ensure the growth of the plant. They consist of small cells that are actively divided, and then differentiated, forming any other type of fabrics. The tops are on the tips of the stems and the roots, the side - inside the stem, under cover, insert - in the bases of intersals, wounds - at the place of damage.

Pokrovny

They are characterized by thick cell walls consisting of cellulose. They play a protective role. There are three types: epiderma, crust, cork. The first covers all parts of the plant. It can have a protective wane, also there are hairs, stomach, cuticle, pores. The crust is characterized by the fact that it has no pores, in all other characteristics it is similar to the epiderm. The plug is dead coating fabrics that form a bark of trees.

Conductive

These fabrics are two varieties: Xylem and Floem. Their functions are transport of dissolved substances from the root to other organs and vice versa. Xylem is formed from vessels formed by dead cells with solid shells, no transverse membranes. They transport liquid up.

Floem - Synotoid tubes - living cells in which no cores. Transverse membranes have large pores. With this type of vegetable tissue, substances dissolved in water are transported down.

Mechanical

They also have two types: and sclerenhim. The main task is to ensure the strength of all organs. Colleghima is represented by alive cells with widespread shells that are tightly adjacent to each other. Sclersenchima consists of elongated dead cells with solid shells.

Maintenance

As it is clear from their name, they constitute the basis of all organs of the plant. They are assimilated and spare. The first are in the leaves and the green part of the stem. There are chloroplasts in their cells that are responsible for photosynthesis. Organic substances accumulate in the basin fabric, in most cases it is starch.