The bodies of multicellular animals are made up of different types cells that perform different functions in the body. Each cell type contains not just one cell, but many similar ones. Thus, we usually talk about types of fabrics (in in this case animals) rather than cell types.
Tissue is made up not only of cells, but also of the substance between these cells. This substance is secreted by tissue cells and is called intercellular. Tissues differ from each other including the amount of intercellular substance. In some animal tissues there is a lot of it, in others the cells are tightly adjacent to each other and there is almost no intercellular substance.
Thus, textile is a collection of cells that have a similar structure and function, as well as secreted by these cells intercellular substance .
There are four main types of animal tissue: integumentary, connective, muscle and nervous. Each type of fabric has its own subtypes. Therefore, they say, for example, not about connective tissue, but about connective tissues.
Integumentary tissues
Integumentary tissues are called differently epithelial.
Integumentary tissues line not only the surfaces of the body, but also the cavities internal organs. So the stomach, intestines, oral cavity, bladder etc. line the inside with integumentary tissues.
There is almost no intercellular substance in epithelial tissues. Their cells adhere tightly to each other and form from one to several layers.
The main functions of the epithelium are protection, secretion production, gas exchange, absorption, and excretion.
is expressed in the protection of the deeper tissues of the animal from damage, temperature changes, and harmful microorganisms. This function is performed by the skin.
epithelium is characteristic of the intestine. Here nutrients are absorbed into the blood using the intestinal villi.
of the animal's integumentary tissue is observed in the stomach, where its cells secrete mucus. There are also various glands in the skin.
carried out by the epithelium of the lungs; in some animals the skin also takes part in gas exchange.
performs the epithelium of the excretory organs.
Connective tissues
Unlike integumentary tissues, connective tissue contains a lot of intercellular substance, which contains relatively few cells.
Connective tissues form bones, cartilage, tendons, ligaments, fatty tissue, and blood. They perform supporting, protective, connecting and other functions.
Blood is classified as connective tissue, as it connects various organs and organ systems. This is how blood carries oxygen from the lungs to all cells of the body, and carbon dioxide back. From digestive system blood delivers nutrients to cells. Harmful substances transported to the excretory system.
Muscle tissue
Main function muscle tissue- This is to ensure the movement of the animal. This occurs due to the alternate contraction and relaxation of the cells that make up muscle tissue. These processes are controlled by nervous tissue.
Muscle cells have an elongated shape.
There are two main types of muscle tissue: striated And smooth. The first forms the skeletal muscles of the animal. Smooth muscles are part of the internal organs. Smooth muscle cells are elongated, but shorter than those of striated muscle tissue, in which the cells are long with many nuclei.
Nervous tissue
Nervous tissue consists of special cells - neurons. These cells have a body and processes, thus the cell has a stellate shape. There are two types of shoots: short and long. The processes transmit irritations from various organs bodies in the spinal cord and brain (which consist of nervous tissue). Here the information is processed, after which excitation is transmitted from the nervous tissue to the organs, which is the body’s reaction to irritation.
The function of nervous tissue is to coordinate the work of various organs of a complex organism, control it, and respond to influences environment and etc.
Groups of cells have different purposes: some serve as support for the body, others provide nutrition, and others transport substances in the body. They have their own names according to the “work” they do.
Fabrics
A tissue is a group of cells that have a common origin. similar structure and performing a specific function in a living organism.
In some tissues, cells are located very close to each other, in others there are gaps between them - intercellular spaces (intercellular spaces).
Plant integumentary tissues
Integumentary tissues are located on the surface of all plant organs. They protect plants from adverse external influences: drying out, mechanical damage, penetration of pathogenic microorganisms into internal tissues.
Let us consider the structure of integumentary tissue using the example of leaf skin. The skin cells are alive. Most of them are large, tightly adjacent to each other, and transparent. Transparency allows sunlight to penetrate into the leaf. Other skin cells are smaller and green, as they contain chloroplasts. These cells are arranged in pairs and are called guard cells. If they move away from each other, a gap appears between them; if they move closer (closed), the gap disappears. The gap that appears between the guard cells is called stomatal, and the entire formation is guard cells with a stomatal gap - stomata.
In plants that live in dry places, the skin is covered with wax and other substances that enhance the plant’s protection from water evaporation. The skin cells of many plants form hairs. They can for a long time remain alive or quickly die and fill with air, forming a woolly or felt cover on the plant. This cover reflects part sun rays and reduces leaf heating.
Young shoots of trees and shrubs are covered with skin. Older ones have no skin. its cells die and slough off. But even before this happens, a multi-layered covering tissue, a cork, forms under the skin. The cork cells are dead, filled with air, and tightly adjacent to each other. With age, the thickness of the cork layer increases.
There are lentils in the cork. They are loosely interconnected cells. Gases pass freely through the intercellular spaces of lentils, so they, like the stomata in the lentils, ensure gas exchange of the integumentary tissues.
Cork on tree trunks and branches serves as a kind of case that more reliably protects the internal tissues of plants from adverse influences external environment than a single-layer skin. In most trees, the cork is replaced with age by a crust (bark), consisting of many layers of dead cells. A thick crust even more reliably protects tree trunks from mechanical damage (animal gnawing, forest fires, sudden temperature changes).
Animal integumentary tissues
Multicellular animals, like plants, have integumentary coverings epithelial tissue(epithelium). They cover the body of animals from the outside and line the inside of all hollow organs (vessels, Airways, stomach, intestines). The outer epithelial cells are arranged in one or more layers and fit tightly together. They have a flat, elongated or cylindrical shape. The intercellular substance is poorly developed or absent.
The integumentary tissues of animals perform the same function as those of plants: they protect the body from mechanical damage, contribute to the survival of unfavorable conditions, and participate in gas exchange.
In addition, there is glandular epithelium, the cells of which are part of the glands. They perform secretory function secrete special substances (secret): saliva, digestive juices, sweat, milk. The integument of complex animals, such as animals, has multilayered epithelium. It forms the top layer of the skin. As a result of external influences, epithelial cells constantly die and are replaced by new ones.
Sweat and sebaceous glands develop from the outer epithelial cells.
Let's look at the structure plant cell under a microscope.
Oblong cells are visible, tightly adjacent to one another. Each cell has a dense transparent shell, in which in some places there are thinner areas - pores. Under the shell there is a living, colorless, viscous substance - cytoplasm. The cytoplasm moves slowly. The movement of the cytoplasm promotes movement within cells nutrients and air. When strongly heated and frozen, the cytoplasm is destroyed, and then the cell dies. In the cytoplasm there is a small dense body - core, in which one can distinguish nucleolus. By using electron microscope it was found that the nucleus has a very complex structure.
In almost all cells, especially in old ones, cavities are clearly visible - vacuoles (from the Latin word "vacuum" - empty). They're filled cell sap. Cell sap is water with sugars and other organic and inorganic substances dissolved in it.
In the cytoplasm of a plant cell there are numerous small bodies - plastids. At high magnification, the plastids are clearly visible. In cells different organs The number of plants varies. The color of certain parts of plants depends on the color of the plastids and the coloring substances contained in the cell sap. Green plastids are called chloroplasts.
All plant organs are made up of cells. Therefore, the plant has cellular structure
, and each cell is a microscopic component of the plant. The cells are adjacent to one another and connected by a special intercellular substance, which is located between the membranes of neighboring cells. If all the intercellular substance is destroyed, the cells are separated.
Often, living growing cells of all plant organs become somewhat rounded. At the same time, their shells move away from each other in places; in these areas the intercellular substance is destroyed. arise intercellular spaces filled with air. The network of intercellular spaces is connected to the air surrounding the plant through special intercellular spaces located on the surface of the organs.
Each living cell breathes, eats and grows over a period of time. Substances necessary for nutrition, respiration and growth of the cell enter it from other cells and from intercellular spaces, and the entire plant receives them from the air and soil. Almost all substances necessary for cell life pass through the cell membrane in the form of solutions.
CELL DIVISION
Cell division is preceded by division of its nucleus. Before cell division, the nucleus enlarges and usually cylindrical bodies - chromosomes (from Greek words"chromo" - color, "soma" - body). They transmit hereditary traits from cell to cell. 
Before division, the number of chromosomes doubles. All living contents of the cell are also evenly distributed between new cells. So, cell division begins with division of the nucleus and each of the resulting cells contains the same number of chromosomes as the nucleus of the original cell.
Young cells, unlike old ones that are unable to divide, contain many small vacuoles. The nucleus of a young cell is located in the center. An old cell usually has one large vasole, and the cytoplasm, in which 
The nucleus is located adjacent to the cell membrane. Young, newly formed cells enlarge and divide again. So, as a result of cell division and growth, all plant organs grow.
TISSUE CELLS
A group of cells that have a similar structure and perform the same functions is called cloth. Plant organs are composed of different tissues.
A tissue whose cells are constantly dividing is called educational.
Integumentary fabrics protect plants from adverse environmental influences.
Responsible for transporting substances to all plant organs conductive textile.
In cells storing tissues store nutrients.
Photosynthesis occurs in the green cells of the tissue of leaves and young stems. Such fabrics are called photosynthetic.
Mechanical tissue gives strength to plant organs.
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The most important part of the leaf is the leaf blade. The outside of the leaf blade is covered with skin (epidermis). There are no chloroplasts in the skin cells, so it easily transmits light to the main tissues of the leaf. The skin cells adhere tightly to each other and reliably protect the internal tissues of the leaf.
The top of the skin may be covered with a layer of wax or waxy substance, which also carries protective function. They prevent the penetration of pathogenic microorganisms into the leaves, protect the leaf from overheating and excessive evaporation of water. The same role is played by hairs, which are outgrowths of skin cells and sometimes densely cover the leaf. For leaves located horizontally, the skin of the upper and lower sides is slightly different in structure. Among the cells of the integumentary tissue on the underside of the leaf blade are located stomata.
There must be atttttttttttttt
Stoma
- slit hole in the skin (epidermis), surrounded by two guard cells. Serves for gas exchange and transpiration. In the light, with sufficient moisture, the stomata are open, in the dark or with a lack of water, they are closed.
Rice. A-closed, B-open. 1 - guard cells of the stomata, 2 - stomatal slit, 3 - chloroplasts, 4 - adjacent cells of the leaf skin (main epidermis), 5 - thickened cell wall, 6 - thin cell wall.
Mechanism of operation stomata is due to the following structural features of the guard cells: they contain chloroplasts, while the remaining cells of the epidermis do not contain them; guard cells have a thickened wall on the side of the stomatal fissure. In the light, the process of photosynthesis occurs only in the guard cells; the resulting sugars increase the concentration of cell sap, which, due to the laws of osmosis, causes the flow of water into these cells. Turgor pressure increases, and the cells begin to swell, increasing in volume. But this is prevented by the cell wall, especially its thick side facing the stomatal fissure. As a result, the guard cells stretch towards the main epidermis, where the walls are thinner and the thick ones follow the entire cell - the stomata opens. At night, when photosynthesis does not occur, the guard cells return to their place and close - the stomata closes. It was noted that when stomata open, potassium ions move into the guard cells, which also determine an increase in turgor pressure and cell volume
Evaporation in hot weather helps cool the leaves, move water and substances dissolved in it throughout the plant, but if the soil is not sufficiently moistened, it leads to wilting or even death of the plant. There is evaporation of water through the cuticle on the surface of the plant ( cuticular) And stomatal(through stomata).
Under the skin there is chlorophyll-bearing parenchyma ( chlorenchyma ). This tissue forms the pulp of the leaf. This is where the process of photosynthesis occurs. Under upper epidermis located columnar chlorenchyma(textile). Its cells are elongated, tightly adjacent to each other, and contain many chloroplasts. Typically, chloroplasts are oriented in such a way as to maximize energy use sunlight. The layer of columnar tissue is optimally illuminated, and the process of photosynthesis occurs intensively in it.
Plants grown in bright light conditions usually have two or three layers of columnar tissue called leaves.
In plants grown in the shade, with a lack of light, columnar cells form only one thin layer in the upper part of the leaf - they are called shadow cells.
Under the columnar chlorenchyma (tissue) is spongy chlorenchyma(tissue), the cells of which are round or oblong, contain fewer chloroplasts and are loosely located, since large intercellular spaces filled with air develop between the cells. Spongy tissue is adjacent to the lower epidermis. The process of photosynthesis in spongy tissue is not as intense as in columnar tissue, but the processes of transpiration and gas exchange are active here. The air passes through the stomata, enters the intercellular spaces and travels through them to all leaf tissues. Water in a gaseous state, oxygen and carbon dioxide, formed during photosynthesis and respiration, are collected in the intercellular spaces, and from them are released through the stomata. Thus, both types of assimilative tissue are interconnected into a single complex system.
In the center of the leaf there is a large conductive bundle, and on the side there are smaller bunches. In the upper part of the conducting bundle there are sieve tubes and companion cells. Adjacent to them below are elements of water-conducting fabric - vessels And tracheids. The conducting bundle of the sheet also contains mechanical fabric, which is located either in the form of a closed ring, or in separate sections at the top and bottom. The mechanical fabric strengthens the conductive bundles and gives the sheet mechanical strength.
On the surface of the sheet, conducting bundles clearly appear in the form veins.
The nature of the arrangement of veins in a leaf (venation) is an important systematic feature.
Leaf venation is:
ü arc(lily of the valley leaf);
ü parallel(cereal leaf).
Arc and parallel venation are characteristic of monocotyledonous plants.
Dicotyledonous plants are characterized by reticulate venation:
ü palmate, when all the veins converge at one point at the base of the leaf blade (Tatar maple);
ü feathery, when the central vein is pronounced (leaf of bird cherry, birch).
| Leaf fabric | Structure | Function |
| cover tissue | The upper skin is formed by tightly pressed transparent cells (4) of irregular shape. Often covered cuticle or hairs | Facing the sun, protection from external influences and evaporation |
| The lower skin usually has stomata. The stomata are formed by two guard cells (2), the walls of which are thickened on one side, with a stomatal fissure (1) located between them. Guard cells have chloroplasts (3). | Located on the underside of the sheet. Protection, breathing and evaporation | |
| Main fabric: columnar | Tightly lying cylindrical cells with chloroplasts | Located on the upper side of the sheet. Serves for photosynthesis |
| spongy | Round cells with intercellular spaces forming air cavities contain less chlorophyll | Located closer to the underside of the leaf. Photosynthesis + water and gas exchange |
| Mechanical | Leaf vein (fiber) | Elasticity and strength |
| Conductive | Leaf vein: - vessels | Flow of water and minerals from the root |
| - sieve tubes | Water flow and organic matter to the stem and root |
Ø C2. What type of leaf is shown in the picture? Which parts of the sheet are indicated in the figure by numbers 1 and 2 and what functions do they perform? 1) a simple leaf with reticulate veins and stipules; 2) 1-leaf blade, performs the functions of photosynthesis, gas exchange, transpiration, and in some plants - vegetative propagation; 3) 2 - veins provide transport of substances and support of the leaf.
