Epithelhülle

Epithelhülle, also known as an epithelial sheath, is a term used in biology and medicine to describe a layer of epithelial cells that surrounds or encloses another structure. This can refer to various anatomical contexts. In the field of neuroscience, it commonly describes the epithelial sheath that surrounds nerve fibers, particularly the myelin sheath in peripheral nerves. This sheath is derived from Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system, which are specialized glial cells that form the myelin.

In other contexts, epithelhülle can refer to the epithelial lining of glands or ducts. For example, the salivary glands are surrounded by a connective tissue capsule, but their secretory portions and ducts are lined with epithelial cells, which could be considered an epithelhülle in a broader sense. Similarly, the epithelial layer lining the urinary tract or the digestive tract could be described as an epithelhülle for the underlying tissues. The specific function of an epithelhülle depends on its location and the type of epithelial cells involved, but it generally serves to protect, compartmentalize, or facilitate the function of the structure it encloses. It plays a role in insulation, nutrient transport, and barrier formation.