The organisms of all animals and plants on the planet are made of tissues. They are different, and each type of fabric has its own function.
What are fabrics made of?
The smallest structural part of the body is the cell. All types of tissues, both vegetable and animal, are composed of them.
Cell structure
This structure can exist as a separate organism. One cell represents such creatures as bacteria and protozoa eukaryotes. This component of a living organism consists of the following parts: the plasma membrane, the cytoplasm, represented by a colloidal solution, the nucleus and organelles - permanent structures, each of which performs certain functions. In the structure of an animal cell, there are such organelles: a cell center, ribosomes, lysosomes, mitochondria, the Golgi complex and the endoplasmic reticulum. Plant cells differ from them in that they contain vacuoles (at first, several, and as the cells age, they merge into one central one), as well as plastids: chromoplasts, leukoplasts, and chloroplasts.
The plasma membrane of an animal cell consists of three layers: two protein and lipid between them. This shell, in turn,surrounded by glycocalyx, which includes polysaccharides, glycolipids, glycoproteins. Organelles perform the following functions: cell center - distribution of chromosomes during division, ribosomes - protein synthesis, lysosomes - breakdown of substances with the help of enzymes, mitochondria - energy production, Golgi complex - accumulation and transformation of certain substances, endoplasmic reticulum (reticulum) - transport of chemical compounds. The number of some organelles in a cell depends on what type of tissue it is part of.
Structure of animal tissues
Animal tissue consists of cells united by an intercellular substance. Depending on the purpose of the fabric, it may have a different composition, be contained in a larger or smaller amount. Animal tissues exist in the following types:
- connective;
- epithelial;
- nervous;
- muscular.
Connective tissues
They are of the following types: dense and loose fibrous, cartilaginous, bone, blood and lymph, adipose, reticular tissue. All of them are united by the presence of a large amount of intercellular substance. Dense fibrous tissue consists mainly of fibers, loose fibrous tissue consists of an amorphous mass. Bone has a large amount of solid intercellular substance, consisting of inorganic chemical compounds. The intercellular substance of cartilage tissue consists of organic substances. Reticular tissue contains stem cells from which blood cells are formed. The blood and lymph contains a large number ofliquids. The structure of animal tissue of this type consists of specific cells, they are also called blood cells. Their types:
- erythrocytes;
- leukocytes;
- platelets.
Each of them performs its functions. Erythrocytes are presented in the form of round structures containing hemoglobin. They are responsible for transporting oxygen throughout the body. Leukocytes perform an immune function. Platelets are responsible for blood clotting when the skin is damaged.
Animal epithelial tissue
The epithelium is divided into several types:
- flat;
- cubic;
- cylindrical;
- ciliated;
- touch;
- glandular.
Squamous epithelium is represented by flattened cells that have the shape of polygons. This tissue is found in the cavity of the esophagus and mouth. Cubic epithelial tissue of animals lines the tubules of the kidneys, cylindrical - the stomach and intestines, ciliated - the respiratory tract, sensory - the nasal cavity. The glandular is a component of the glands. The cells of this particular tissue produce hormones, milk, etc.
Muscle tissue
They are also divided into several types:
- striped;
- smooth;
- hearty.
Muscular animal tissue of the first type is a component of the muscles of the musculoskeletal system. Muscles of internal organs are formed from the smooth one, for example, the intestines, stomach, uterus, etc. The cardiac differs in that its fibers are intertwined with each other - thisallows them to shrink faster.
Nervous tissue of animals
This type of tissue consists of spindle-shaped, stellate or spherical cells - neurons, and intercellular substance - mesoglea, which provides neurons with nutrients. Neurons are made up of a body, an axon, and dendrites, the processes by which cells are connected. They are needed to conduct the signal.
