Metaplasia

Under metaplasia is defined as a transformation of a differentiated tissue ( epithelial or mesenchymal ) or cell type to another. Metaplasia is partially reversible; if the irritation persists. This is a qualitative change of body cells that initially attracts no change in cell number by itself.

Basically, the metaplasia can occur in all tissues, has been in the practice of medicine but especially for the epithelia of particular importance.

An irreversible cell transformation is called anaplasia; Higher transition of differentiated cells in less differentiated cells.

Causes

Under normal circumstances, are all components of a tissue in a balance between renewal and consumption of their cells ( cell death ) and their intercellular substances.

Metaplasia is a special form of cellular adaptation to the environment. By continuing mechanical, chemical or inflammatory stimuli often used in conjunction with the change in the environment or the cellular milieu, it comes to replacement of surface epithelium by another, usually inferior epithelium; or to a change, usually inferior cell performance.

A direct metaplasia ( transdifferentiation ) is not possible, but on the basis of the stem cells ( basal or reserve cells ) of the epithelium is formed another, different differentiated cell.

Species

We distinguish between different forms: squamous metaplasia, Glandular metaplasia, intestinal metaplasia, Gastric metaplasia.

• Myeloid metaplasia

Under pathological conditions (such as in leukemia ), the spleen begin production of granulocytes and erythrocytes again, which takes place during embryonic development in it. This process is known as myeloid metaplasia.

• Barrett 's esophagus

Is referred to as Barrett's esophagus, a conversion of metaplastic epithelium of the esophagus.