Quick Facts
The basement membrane is a thin sheet of amorphous extracellular material upon which the basal surfaces of epithelial cells rest; other cells associated with basement membranes are muscle cells, Schwann cells, and fat cells. The membrane is interposed between the cellular elements and the underlying connective tissue. It usually comprises two layers, the basal lamina and the reticular lamina, and is composed of Type IV collagen (which is unique to basement membranes), laminin, fibronectin, and heparan sulfate proteoglycans (Dorland, 2011).
Related parts of the anatomy
Structure
The basement membrane is a layer within the vessel wall on which the endothelium lies, dividing the endothelium from the connective tissue in the vessel wall. The basement membrane is made up of two layers, the basal lamina and the reticular lamina. These two laminae are comprised of different matrices. The basal lamina is a matrix of collagen formed by the endothelial cells. The reticular lamina is deep to the basal lamina and composed of reticular fibers produced by fibroblasts.
Anatomical Relations
The basement membrane separates the endothelium from the connective tissue in the vessel walls.
Function
The basement membrane contributes to physical support of the vessel, holding the endothelium to connective tissue. This membrane also functions as a defense against harmful cells infiltrating the deeper tissue levels (Liotta et al., 1980). It also plays a role in angiogenesis through the release of peptide fragments.
List of Clinical Correlates
- Alport syndrome
- Formation of tumors (Figg and Folkman, 2008)
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Figg, W. D. and Folkman, J. (2008) Angiogenesis: An Integrative Approach from Science to Medicine. Springer US.
Liotta, L. A., Tryggvason, K., Garbisa, S., Hart, I., Foltz, C. M. and Shafie, S. (1980) 'Metastatic potential correlates with enzymatic degradation of basement membrane collagen', Nature, 284(5751), pp. 67-8.
