Animal tissue is a collection of cells that are connected by an intercellular substance and are intended for a specific purpose. It is divided into many types, each of which has its own characteristics. Animal tissue under a microscope can look completely different, depending on the type and purpose. Let's take a closer look at the different types.
Tissue of the animal body: varieties and features
There are four main types: connective, epithelial, nervous and muscular. Each of them is divided into several types, depending on the location and some distinctive features.
Animal connective tissue
It is characterized by a large amount of intercellular substance - it can be both liquid and solid. The first type of this type of tissue is bone. The intercellular substance in this case is solid. It consists of minerals, mainly phosphorus and calcium s alts. Also cartilaginous animal tissue belongs to the connective type. It differs in that its intercellular substance is elastic. She inin turn, it is subdivided into such types as hyaline, elastic and fibrous cartilage. The most common in the body is the first type, it is part of the trachea, bronchi, larynx, large bronchi. Elastic cartilages form the ears, medium-sized bronchi. Fibrous are part of the structure of the intervertebral discs - they are located at the junction of tendons and ligaments with hyaline cartilage.
Connective tissue also includes adipose tissue, in which nutrients are stored. In addition, this includes blood and lymph. The first of these is characterized by specific cells called blood cells. They are of three types: erythrocytes, platelets and lymphocytes. The former are responsible for the transport of oxygen throughout the body, the latter for blood clotting in case of damage to the skin, and the third perform an immune function. Both of these connective tissues are special in that their intercellular substance is fluid. Lymph is involved in the metabolic process, it is responsible for returning various chemical compounds from tissues back to the blood, such as all kinds of toxins, s alts, and some proteins. Loose fibrous, dense fibrous and reticular tissues are also connective. The latter differs in that it consists of collagen fibers. It acts as the basis for internal organs such as the spleen, bone marrow, lymph nodes, etc.
Epithelium
This type of tissue is characterized by the fact that the cells are very close to each other. epithelium inmainly performs a protective function: it consists of the skin, it can line the organs both from the outside and from the inside. It is of many types: cylindrical, cubic, single-layered, multi-layered, ciliated, glandular, sensitive, flat. The first two are named so because of the shape of the cells. The ciliary has small villi; it lines the intestinal cavity. All the glands that produce enzymes, hormones, etc. consist of the following type of epithelium. The sensitive one acts as a receptor, it lines the nasal cavity. The squamous epithelium is located inside the alveoli, blood vessels. Cubic is found in organs such as the kidneys, eyes, thyroid gland.
Nervous animal tissue
It consists of spindle-like cells - neurons. They have a complex structure, built from a body, an axon (a long outgrowth) and dendrites (several short ones). These formations of the cells of the nervous tissue are interconnected, along them, like wires, signals are transmitted. Between them there is a lot of intercellular substance that keeps the neurons in the right position and nourishes them.
Muscle tissue
They are divided into three types, each of which has its own characteristics. The first of these is smooth muscle tissue. It consists of long cells - fibers. This type of muscle tissue lines such internal organs as the stomach, intestines, uterus, etc. They are able to contract, but the person (or animal) himself is unable to control and manage these muscles on his own. The next view is striatedthe cloth. It contracts many times faster than the first, as it contains more actin and myosin proteins, due to which this happens.
Striated muscle tissue makes up skeletal muscle, which the body can control at will. The last type - cardiac tissue - differs in that it contracts faster than smooth tissue, has more actin and myosin, but is not subject to conscious control by a person (or animal), that is, it combines some features of the two types described above. All three types of muscle tissue are made up of long cells, also called fibers, which usually contain a large number of mitochondria (energy-producing organelles).
