Integumentary system

The integument (Latin integumentum " top", " envelope ", " outer skin " ) refers to the relation to the remaining tissue differentiated outer body shell in all tissues animals. The term does not imply any anatomical, but a functional approach.

Functions

The basic function of an integument must fulfill two functions providing conflicting requirements. On one hand, there must be a protection of the organism against external influences such as mechanical stress and unhealthful chemical environment offer ( homeostasis), on the other hand, it must contact of the organism with the outside world to make sure. Many groups of organisms have to converge to each other a stable mechanical outer shell developed are incorporated into the sense organs and glands with different functions. For many groups of organisms and the gas exchange (respiration) via the integument takes place. The arthropods have to special organs, the trachea developed that represent invaginations of the integument inside the body.

In addition to these basic functions of the integument has in many groups of organisms a variety of special functions. Color pattern and other special developments of the skin of vertebrates serve eg as a signal for social communication ( eg, gender invention and discovery ). In many species the integument for protection from enemies is armor- reinforced ( in vertebrates: Osteoderm ), it can form attachments to such venom glands, thorns and spines. Dandruff, hair and feathers with their many functions are also special training of the integument.

Only in recent years are better known further functions of the integument, such as in the hormone system and the immune system.

Anatomy

Anatomically there are integuments depending on group of organisms from a variety of tissue types of very different shape, origin and complexity. The simplest form is a shell of a single, differentiated cell location. This is usually referred to as epidermis. An epidermis is a special case of a deck tissue or epithelium. You already occurs in the original tissue animals with only two cotyledons ( Diploblasten ) such as the cnidarians on. The integument is here out of the outer germ-layer or ectoderm. In numerous anatomically complex organisms such as vertebrates and the mesoderm at the Integumentbildung is involved.

The integument of vertebrates, including humans, is called skin. It consists of connective tissue components ( dermis) and the top layer (epidermis ) and skin appendages. An important component of the structural protein keratin fibers are. The integument of arthropods forms a secluded from the epidermis to the outside, very complex structure exoskeleton. In addition to numerous proteins is the nitrogen-containing polysaccharide chitin one of the main components.