Integumtary System: Epidermis Flashcards
Define the Epidermis:
Most superficial layer of skin
Tissue Type: Stratified squamous epithelium
varies in thickness,
Avascular- NO blood vessels
Constantly renewing itself
Define the Stratum Corneum layer:
Most superficial layer of the epidermis
Several Layers of horny cells
Contains: flattened dead skin cells + keratin
Constantly shedding of Apical(top) layers as basal cells divide
Define Keratinocytes:
Skin cells that produce keratin
Define Keratin:
Protein in skin for strength + prevents dehydration
in hair + nails
Define the Stratum Lucidum:
“Translucent”
Clear, transparent
Contains: dead karatinocytes + keratin
Only in thick skin on palms + soles of feet
Define the Stratum Granulosum:
“Graveyard”
Contains: Dying keratinocytes + keratin
Cells die in this layer
Define the Stratum Spinosum:
Contains: Living keratinocytes
Appears “Spiny” due to bundles of keratin proteins
Define the Stratum Basale:
Bottom Layer
Contains: Single-raw mitotically active stem cells
Melanocytes- specialized cells that make melanin
Define a Stem Cell:
Specialized cell that cna divide continuously into keratinocytes
Define Melanin:
Brown, black pigment that protects skin against UV radiation of sun
Amount of melanin present in skin determines for skin tone