Skin Flashcards
What system is the skin part of?
Integumentary system
What is the superficial layer of the skin called?
Epidermis
What is the deeper layer of skin called?
Dermis
What are the 2 major classes of skin?
Hirsute and Glabrous
What are the qualities of Hirsute skin?
Thin, hairy, covers greater part of the body
What are the qualities of Glabrous skin?
Thick, hairless, covers the surfaces of palms, soles and flexor surfaces of the digits
What are the 5 layers of the epidermis? (most superficial to lowest)
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
What is the functions of the stratum corneum?
Provides a mechanical and protective layer against abrasion, light, heat and chemicals
How many layers of Keratinocytes does the stratum corneum have?
25-30 (dry and dead, filled with keratin)
What do keratinocytes in the stratum corneum do?
Help prevent microbes and dehydration of deeper tissues
What do Lamellar granules in the stratum corneum do?
Help to make the skin water repellent
Where is the stratum lucidum found?
Thick skin of palms, digits and soles of feet
What does the stratum corneum look like?
Smooth, almost translucent
What are the keratinocytes in the stratum lucidum like?
Dead and flattened - packed with eleidin
What is Eleidin, how is it produced and what does it do?
A clear protein, produced from Keratohyalin, provides a barrier to water
What do Keratinocytes do?
Produce the protein keratin, which helps protect the skin and underlying tissue from heat, microbes, chemicals, produce lamellar granules which release a waterproof sealant
What does the stratum granulosum represent?
The transition between the deeper, metabolically active strata and the dead cells of the more superficial strata
How many layers does the stratum granulosum contain and what kind of cells are they?
3-5 layers of flat dying cells that show nuclear degeneration
How are lamellar granules water repellent?
They release lipid that repels water
What granules does the stratum granulosum contain?
Lamellar granules and dark-staining keratohyalin granules
How do Keratohyalin granules make keratin?
Convert tonofilaments into keratin
What is the appearance of the stratum granulosum and why?
2 proteins (lamellar and keratohyalin granules) make up the keratinocyte mass in the stratum granulosum and give it a grainy appearance
What is the function of the stratum spinosum?
provides strength and flexibility to the skin
How many layers of keratinocytes does the stratum spinosum contain and why?
8-10 layers - formed because of cell division in the stratum Basale (layer below)