duct of eccrine sweat gland

Continuous with the secretory coil and running toward the skin surface, the duct of the eccrine sweat gland is built of simple tubular epithelium arranged in two cell layers, basal and luminal. Its principal function is not conduction alone but reabsorption: sodium and chloride ions are recovered from sweat as the fluid flows along the lumen, and most of that ion reabsorption occurs in the proximal part of the duct. The distal segment is comparatively straight and connects with the acrosyringium, the intraepidermal portion of the duct within the epidermis. The duct therefore modifies the composition of the fluid delivered by the secretory coil before it reaches the surface, which is why its two-layered epithelium is described in terms of transport rather than of secretion.