Skin Flashcards
2 layers of skin and 3rd (false) layer
- epidermis - stratified squam.
- dermis - dense irreg. CT
- hypoderm. - loose CT with adipose
2 types of skin
- thick - thick epi, no hair, palms and soles
2. thin - everywhere else
5 layers of epidermis
- stratum basale
- stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
Feat. of basale
- at basement membrane
- anchored by hemidesmosomes
- layer of proliferation
Feat. of spinosum
- many desmosome connections
- begin to dev. squamous shape
Feat. of granulosum
- cells have squamous shape
- fill with keratohyaline and lammelar granules
- mix to start forming keratin
- creates water barrier and superior cells are cut off from diffusion
feat of lucidum
- inconsistent band
feat. of corneum
- layer of dead, keratin filled cells
4 cell types of epidermis
- keratinocytes
- melanocytes
- langerhans
- merkle
feat of keratinocytes
- most numerous
- accumulate keratin and melanin
- synthesize vit D precursor
feat of melanocytes
- occupy basal layer
- 5-10% of cells
- synthesize menanin to go to keratinocytes
feat of langerhans
- 5% of cells pop
- antigen presenting
feat of merkle cells
- located in stratum basale
- play role in mechoreception
2 layers of dermis
- papillary - loose connective tissue
2. reticular - denser connective tissue
feat of papillary layer
- dermal ridges and papillae increase contact
- blood supply to nourish epidermis
feat of reticular layer
- coarser bundle of conn. fibers
- regional orientation creates langer’s lines - incisions
feat. of blood supply of skin
- epidermis is avascular
- subcutaneaous vessels > reticular layer
- cutaneous vessels to subpaillary > papillary layer
- arteriovenous shunts open to move blood away from surface
where are skin appendages derived from
epidermis
4 appendages of the skin
- hair follicles
- sebaceous glands
- eccrine sweat glands
- apocrine sweat glands
feat of hair follicles
- thin skin only
- tubal invaginations of epidermis
- keratinized cells that are generated at stem or base
feat. sebaceous glands
- cells connected to hair follicle by short duct
- cells at periphery divide
feat. of eccrine sweat glands
- found throughout
- coiled tube glands that extend into hypodermis
- ducts penetrate epidermis
- release watery sweat
feat of appocrine sweat glands
- only in armpits and groins
- oilier substance
