Human fingerprint. The smaller circles within the epidermal ridges are sweat gland ducts. No two fingerprints, even from identical twins, are said to be exactly alike. SEM X35 | Richard Kessel photo, visuals unlimited
Skin, lateral cut A section through human skin. The skin layers, from top to bottom, are the stratum corneum, composed of flattened, dead skin cells that form the surface of the skin. The dead cells from this layer are continuously being shed and replaced by cells from the living epidermal layer below (red). The lowest layer seen here is the dermis. In the middle, a sweat gland can be seen.