Integumentary Review

outermost protective shield composed of layers of epithelial cells

makes up bulk of the skin, strong & flexible, tough leathery layer of dense connective tissue

subcutaneous tissue just deep to the skin sharing some of the skins protective functions

most superficial layer; 20-30 layers of dead cells, essentially flat membranous sacs filled with keratin. Glycolipids in extracellular space.

epidermal layer absent in thin skin; 2-3 layers of clear, flat, dead, keratinocytes with indistinct boundaries.

typically one to 5 layers of flattened cells, organelles deteriorating ; cytoplasm full of lamellar granules (releasing lipids) and keratohyaline granules.

Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin.

deepest epidermal layer; one row actively mitotic stem cells; some newly formed cells becoming part of more superficial layers. See occasional melanocytes and dendritic cells. AKA - stratum germanitivum

located in epidermis, chief role is producing keratin, majority of edipermal cells

spider shaped epithelial cells that synthesize melanin, found in deepest layer of epidermis

arise from bone marrow to migrate to epidermis, ingest foreign substances and key activators of immune system, aka Langerhans cell

a sensory receptor for touch in the epidermis, present at epidermal junction shaped like a spiky hemisphere, and associated with a disc-like nerve ending.

fibrous protein that gives epidermis protective properties

cells junctions that are "like velcro" connecting cells and producing a tension-resisting network.

made in skin, polymer of tyrosine amino acids; forms a pigment shield on the sunny-side of keratinocytes that protects from UV radiation.