Animal tissue - varieties and their features
Animal tissue is a collection of cells thatare interconnected by an intercellular substance and are intended for a specific purpose. It is divided into many species, each of which has its own characteristics. Animal tissue under a microscope can look absolutely different, depending on the type and purpose. Let's take a closer look at the different species.
Animal tissue: 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.
Connective animal tissue
It is characterized by a large numberintercellular 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 mineral substances, mainly salts of phosphorus and calcium. Also, the connective type is a cartilaginous animal tissue. It is distinguished by the fact that its intercellular substance is elastic. It, in turn, is divided into such species 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 ears, medium-sized bronchi. Fibrous enter the structure of intervertebral discs - they are located at the junction of tendons and ligaments with hyaline cartilage.
To adherent and adipose tissue, inwhich stores nutrients. In addition, this includes blood and lymph. For the first of them, specific cells, called blood corpuscles, are characteristic. They come in three forms: erythrocytes, platelets and lymphocytes. The first are responsible for the transport of oxygen through the body, the second - for blood coagulability in skin lesions, and still others perform the immune function. Both of these connective tissues are special in that their intercellular substance is liquid. Lymph is involved in the process of metabolism, it is responsible for the return from the tissues back to the blood of a variety of chemical compounds, such as all kinds of toxins, salts, certain proteins. Connecting fibers are also loose, dense fibrous and reticular tissues. The latter differs in that it consists of collagen fibers. It acts as the basis for such internal organs as the spleen, bone marrow, lymph nodes, etc.
Epithelium
This type of tissue is characterized by the fact that cellslocated very tightly to each other. Epithelium basically performs a protective function: it consists of the skin, it can lash the organs both from the outside and from the inside. It can be of many types: cylindrical, cubic, single-layered, multilayered, ciliate, glandular, sensitive, flat. The first two are called because of the shape of the cells. The ciliated has small villi, it lays the cavity of the intestine. The following form of the epithelium consists of all glands that produce enzymes, hormones, etc. The sensitive acts as a receptor, it lays the nasal cavity. The flat epithelium is located inside the alveoli, vessels. Cubic is found in organs such as the kidneys, eyes, and the thyroid gland.
Nervous animal tissue
It consists of spindle-like cells - neurons. They have a complex structure, built of a bull, an axon (a long outgrowth), and dendrites (several short ones). With these formations the cells of the nervous tissue are connected to each other, signals are transmitted along them, as in wires. Between them there is a lot of intercellular substance that supports the neurons in the right position and feeds them.
Muscular tissues
They are divided into three types, each of whichhas its own characteristics. The first of these is smooth muscle tissue. It consists of long cells - fibers. This kind of muscle tissue lays such internal organs as the stomach, intestines, uterus, etc. They are able to contract, but the person (or animal) is unable to control and control these muscles by himself. The next species is striated tissue. It shrinks many times faster than the first, because it contains more actin and myosin proteins, thanks to which it happens.
