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Medical Term:

basal lamina


Definition: an amorphous extracellular layer applied to the basal surface of epithelium and also investing muscle cells, fat cells, and Schwann cells; thought to be a selective filter and to serve both structural and morphogenetic functions. Its principal component is a layer (consisting mostly of type IV collagen) called the lamina densa, which has a dense appearance under the electron microscope. On either side of the lamina densa are two less dense layers, called the lamina rarae.

Synonym(s): lamina densa

See Also: basement membrane, lamina densa