Basal Laminas and Epithelia

The basal lamina, a thin meshwork of extracellular matrix (ECM) molecules, separates most epithelia and other organized groups of cells from adjacent connective tissue. Together, the basal lamina and collagenous reticular lamina form a structure called the basement membrane. 

The basal lamina (basement membrane). This is a dense complex of macromolecules, forming a sheet that underlies epithelia and surrounds muscle cells. 

Figure 1.10 Columnar and stratified epithelia. Epithelial b ssues are underlain by a basement membrane which is a composite structure composed of an amorphous basal lamina, secreted by the epithelial cells, and a more fibrous reticular lamina derived from connective tissue.

In summary, there is strong evidence from observations of axon behaviour that factors located on epithelia and/or basal laminae can guide axons. Experimental studies have shown that the role of the basal lamina may be redundant when it is associated with an epithelium. 

In common with all epithelial interfaces (see Section 1.3.2), the epithelium of the oral cavity is supported by a basement membrane, which separates the epithelium from the underlying connective tissue layer (the lamina propria) (Figure 7.1). Oral epithelium is broadly similar to stratified squamous epithelia found elsewhere in the body, for example the skin (see Section 8.2.1), in that cells are produced by mitosis in the basal layer of the epithelium and these proliferating cells push existing cells towards the surface. The phases of this dynamic process are represented in four morphological layers ... 

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