Tuesday, November 6, 2012

Epidermis

The epidermis is the exterior layer of squamous, overlapping, epithelial cells which constitute tha skin. The epidermis has no blood vessels and consists of five sub-layers of cells: 1) stratum basale, which is the deepest layer that is constantly producing new cells which move upward, replacing the older dead epithelial cell on the surface; 2) stratum spinosum, which is composed of prickle cells; 3) stratum granulosum, composed of granular cells containing lamellar granules; 4) stratum lucidum, which is a translucid dead cell layer; 5) stratum corneum, which consists of flat dead cells, filled with keratin, that form the outer skin layer.