Tegument (helminth)

The neodermis or the tegument is a "secondary body cover " in members of the Neodermata to which the tapeworms ( Cestoda ), the Hakensaugwürmer ( Monogenea ) and the trematodes ( Trematoda ) belong, as well as the scratch worms ( Acanthocephala ).

Neodermis the Neodermata

The neodermis is formed from cells of mesodermal origin and replaces the original epidermis. This is done by larval existing mesodermal tissues, which pushes through foothills below the epidermis and this replaces. The individual cells of the neodermis merge afterwards into a single tissue without cell boundaries, which is described as syncytia and the cell nuclei more inside the body, below the basal matrix are. The formation of the neodermis occurs in the development of a first parasitic Erstlarven in shape.

Tegument of the Acanthocephala

The tegument can be at the very large species up to two millimeters thick and will, as well as many other tissues of these animals, formed by a syncytium. The basis of this cell association in most species about 6 to 20 individual cells, the adjacent cell membranes dissolve and thus group specific form a fabric with many small or much less very large nuclei. The nuclei increase in size during development and are polyploid by constant mitosis, in many species they branch out and reach diameters of up to two millimeters. Especially for large styles disintegrate the cell nuclei without mitotic division into many small fragments. In the epidermis are also collagen fibers which extend to the outside of the body mainly parallel to the direction and in the lower layers to stabilize the ring and epidermis. The outermost region is denser than the inner, but does not form a tank. This layer is traversed by numerous invaginations that form a complex lacunar which serves the diet.

Documents

• Anatomy (eddy lots)