17 terms

Stratum Germinativum, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum , Stratum Corneum

stratum germinativum
innermost epidermal layer; aslo called stratum basale. is relatively dry and water resistant, but not water proof.
epidermal ridges
formed by the stratum germinativum which extend into the dermis and are adjacent to dermal projections
dermal papillae
dermal projections; project into the epidermis(nipple shaped mound)
dermal papillae and epidermal ridges
are significant because the strength of the attachment is proportional to the surface area of the basal lamina.
basal cells
or germinative cells, dominate the stratum germinativum. They are stem cells whose divisions replace the more superficial keratinocytes that are lost of shed at the epithelial surface.
merkel cells
sensitive to touch, when compressed, they release chemicals that stimulate sensory nerve endings.
Stratum Spinosum
consists of 8 to 10 layers of keratinocytes bound together by desmosomes; means spiny layer, refers to the fact that the cells look like miniature pincushions in standard histological sections.
dendritic cells
they participate in the the immune response by stimulating a defense against microorganisms that manage to penetrate the superficial layers of the epidermis, and superficial skin cancers.
stratum granulosum
superficial to the stratum spinosum, also called grainy layer. Consist of three to five keratinocytes derived from teh stratum spinosum.
a tough fiberous protein, is the basic structural component of hair and nails in humans.
forms dense cytoplasmic granules that promote dehydration of the cell as well as aggregation and cross-linking of the keratin fibers.
Stratum lucidum
cover the stratum granulosum
stratum corneum
contains 15 to 30 layers of keratinized cells. Located at the exposed surface of thick and think skin
or cornification, is the formation of protective, superficial layers of cells filled with Keratin. The process occurs on all exposed skin surfaces except the anterior surfaces of the eyes.
insensible perspiration
water from interstitial fluids slowly penetrates the surface, to be evaporated into the surrounding air causing you to loose roughly 500 ml of water. Unable to feel the water loss.
sensible perspiration
produced by active sweat glands
excessively dry skin; consequence of severe burns