Basal laminas composition

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.

This chapter describes the organization of the major proteins that form a basal lamina which connects an epithelium to its underlying stroma (Sect. 1). The organization and major protein composition of oral and gingival epithelium and the junctional epithelial dental attachment at the base of a gingival sulcus are described (Sect. 2). 

Basal cells that stop dividing also stop secreting a basal lamina and lose their attachment. They are squeezed by adjacent, dividing basal cells into the body of the junctional epithelium and are expelled into the base of a sulcus. The few tight junctions in the body of the junctional epithelium are consistent with its permeability to interstitial fluid. The rapidly dividing cells of both internal and external basal layers express K5 and K14 like all stratified epithelial basal cells, but the interior cells express K4 and K13, not K1 and K10 (Fig. 5.11). The composition of the internal basal lamina is described in Fig. 5.7b. 

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