Animal tissue - varieties and their features

Animal tissue is a collection of cells that are interconnected by an intercellular substance and are designed 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 differently, 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 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 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 subdivided 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 connective also applies fatty tissue in which nutrients are stored . 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 former are responsible for the transport of oxygen through the body, the latter 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, some proteins. Connective are also loose fibrous, 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 the cells are located very tightly to each other. Epithelium basically performs a protective function: the skin consists of it, it can cover the organs both from the outside and from the inside. It can be of many kinds: cylindrical, cubic, single-layered, multilayered, ciliate, glandular, sensitive, flat. The first two are named because of the shape of the cells. The ciliated has small villi, it lays the cavity of the intestine. The following type of epithelium consists of all glands that produce enzymes, hormones, etc. Sensitive serves as a receptor, it lining 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, which supports the neurons in the right position and feeds them.

Muscular tissues

They are divided into three types, each of which has its own characteristics. The first of these is a 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 fabric. It shrinks many times faster than the first, since it contains more proteins of actin and myosin, thanks to which it happens. Cross-striated muscle tissue is skeletal musculature, which the body can control at its discretion. The last type - heart tissue - differs in that it contracts faster than smooth, has more actin and myosin, but does not lend itself to conscious control by the person (or animal), that is, it combines some of the features of the two types described above. All three types of muscle tissue consist of long cells, which are also called fibers, they usually contain a large number of mitochondria (organelles that produce energy).