Epidermal Cells

The epidermal cells are attached to the basal lamina by hemidesmosomes, which anchor the cell membrane to collagen fibers in the basal lamina. Near their base, the cells are attached to each other by desmosomes; near their apical end, they are attached to each other by a narrow, impermeable zone (the adhering zonule), effectively separating the cuticular compartment from the lateral space between cells. Below the zonule are bands of septate desmosomes, which may be adhesive, and gap junctions through which the cells can communicate chemically with each other by interchange of low molecular weight compounds.

The cuticular materials (chitin and proteins) are secreted from the apical surface of the epidermal cells into the subcuticular space, or deposition zone, where they are assembled into an intact cuticle. The apical surface is folded into shorter or longer microvilli, depending on the stage of the molting cycle and the secretory activity of the cells.

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