Sweat gland in skin. Light micrograph of a section through the dermis of the skin showing a sweat gland. The gland is composed of a secretory portion (upper left) and several excretory ducts (bottom left to top right). The dermis contains numerous sweat glands, which discharge a watery secretion onto the surface of the skin in order to lower the body temperature. Surrounding the secretory portion are myoepithelial cells (solid purple lines). These contract to expel sweat from the secretory portion into the ducts. Trichrome blue stain. Magnification unknown.