Sweat gland. Coloured scanning electron micrograph (SEM) of a section through a sweat gland pore opening onto the surface of human skin. Sweat pores bring sweat from a sweat gland to the skin surface. The sweat evaporates, removing heat and playing a vital role in cooling the body and preventing it from overheating. Skin cells can be seen flaking off the skin around the pore opening. Sweat pores vary in shape and size over the body. Magnification: x670 when printed 10 centimetres wide.