skin grows from bottom up. not necessarily a single layer
1. Stratum basale (germinitivum) - bottom layer, single layer. sits on basement membrane (stimulate to grow=rubbing, irritation calacus, thus moves up faster)
a. Deepest portion of epidermis and single layer.
b. Mitosis - only layer
2. Stratum spinosum (a little bit of division)
a. Limited cell division.
3. Stratum granulosum
a. Contains keratohyalin.
b. In superficial layers nucleus and other organelles degenerate and cell dies
4. Stratum lucidum
a. Thin, clear zone. Found only in palms and soles (thick part of skin)
5. Stratum corneum
a. Most superficial and consists of cornified (dead, hard, dry) cells