The epidermal-dermal junction.
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.
D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D002448:Cell Adhesion; D002449:Cell Aggregation; D002454:Cell Differentiation; D002462:Cell Membrane / Q000648:ultrastructure; D002465:Cell Movement; D002642:Chick Embryo; D003094:Collagen; D003896:Desmosomes / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008544:Melanocytes / Q000648:ultrastructure; D008564:Membrane Potentials; D010392:Pemphigus / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D012867:Skin / Q000033:anatomy & histology* / Q000166:cytology / Q000648:ultrastructure; D012879:Skin Physiological Phenomena
D007136:Immunoglobulins; D011947:Receptors, Antigen, B-Cell; D003094:Collagen