Sweat pore. Coloured scanning electron micrograph (SEM) of a sweat pore (centre) on a human hand. Sweat is released through holes like this onto the surface of the skin from glands below the surface. The sweat evaporates, and this cools the body by carrying away heat. The surrounding area shows the dead cells making up the surface layer of the skin, the stratum corneum. Magnification: x500 when printed 10cm wide.