The Epidermal-Dermal Junction

Abstract

Ultrastructurally, the epidermal-dermal junction is composed of four component areas:(1) the basal cell plasma membrane with its specialized attachment devices or hemidesmosomes, (2) an electron-lucent area, the lamina lucida, (3) the basal lamina, and (4) the sub-basal lamina fibrous components, including anchoring fibrils, dermal microfibril bundles, and collagen fibers. The light microscopic "basement membrane" comprises only the sub-basal lamina fibrous zone. Other cell types, including melanocytes and Merkel cells, are also found at the epidermal-dermal junction. Structures at the junction derive their origin from the epidermis and dermis: the basal lamina is primarily of epidermal origin, the anchoring fibrils of dermal origin. The junction serves the following functions: (1) epidermal-dermal adherence, (2) mechanical support for the epidermis, and (3) a barrier to the exchange of cells and of some large molecules across the junction.

Quantitative studies of hemidesmosomes during progressive DMBA carcinogenesis in hamster cheek-pouch mucosa

“…The ultrastructural characteristics of hemidesmosomes in normal hamster cheek-pouch epithelium are similar to those reported in other epithelia (Farquhar & Palade, 1963, 1965Susi et al, 1967;Frithiof, 1969;Flickinger, 1970;Geisenheimer & Han, 1971 The most important function of hemidesmosomes appears to be to maintain the attachment of the epithelium to the underlying tissues (Briggaman & Wheeler, 1975). The results of the present investigation and those of McNutt imply that the attachment of epithelium to the connective 30 tissue is impaired during experimental carcinogenesis and in basal-cell carcinomas.…”

“…In the region of the hemidesmosomes a localized thickening was found in the lamina lucida, which was invariably much closer to the plasma membrane than to the lamina densa. This thickening, which has been called the sub-basal dense plaque (Briggaman & Wheeler, 1975), the peripheral density (Stern, 1965) and the Haftplat or H line (Komura & Ofuji, 1972), is visible only on perpendicular or near-perpendicular sections of hemidesmosomes. The lamina densa opposite the hemidesmosomes often appeared to be of increased electron density and thickness.…”

“…Lying beneath the epithelium is a connective tissue of varying composition, and uniting the two at the epithelial-connective tissue junction is a well organized region specialized for the functional adaptation of attachment between tissues of different embryological origins (Briggaman & Wheeler, 1975). Two important components are the basal lamina, with its lamina lucida, lamina densa and associated fibrillar and filamentous elements, and the hemidesmosomes.…”

High-affinity binding of the NC1 domain of collagen VII to laminin 5 and collagen IV

“…One of the distinct morphological features of skin is that it is composed of two principal layers, namely the epidermis and dermis, separated by the basement membrane, a structure that serves as an attachment zone on which structural macromolecules produced by epidermal and dermal cells interact, thereby contributing to the formation of the complex dermal-epidermal junction [33].…”

Clinical features and diagnosis of epidermolysis bullosa acquisita

“…However, cleavage can appear in sublamina densa or lamina lucida zone [113]. Localization of blister in the lamina lucida has been explained by the lamina lucida being the locus minoris resistentiae and thus, most vulnerable to proteolytic enzymes released during the inflammatory reaction at the BMZ [114][115][116]. Thus, transmission electron microscopy cannot be used in differentiating EBA from inherited epidermolysis bullosa and other pemphigoid disorders.…”