Sweat pores. Coloured scanning electron micrograph (SEM) of sweat (light blue) produced by sweat pores on skin from a human hand. Sweat is released 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 areas shows the dead cells making up the surface layer of the skin, the stratum corneum. Magnification: x50 when printed 10cm wide.