integument part 2 Flashcards
corneum
dead cells with hard protein envelope surrounded by lipids
lucidum
dead cells that have keratinohyalin
-only in thick skin
granulosum
-formation of the keratinohyalin and hard protein envelope
-llamelar bodies release lipids
-cells die and nucleus break down
-water barrier formed by lamellar bodies
-non dividing cells are filled with granules of keratin
spinosum
keratinocyte are separates
basal
site of mitosis
-have desmosomes and a basement membrane
langerhans cells
in the prickle cell layer
-macrophages
merkel cell
in the basal cell layer
dermis
connective tissue
water barrie
under karatinized cells above keratohyalin granules
keratinocytes
90% of the epidermal cells
-make keratin
keratin
fibrous protein that waterproofs skin
melanocytes
8% of the epidermal cells that make melanin
-protect karatinocyte dna from sun
-have dendrites , nucleus, rough er, golgi, mitochondrion, melanosome and granules
langerhans
come from red bone marrow that migrate to epidermis
-immune response
-dendritic phagocytic
merkel cells
least amount of these in the epidermis, deepest layer (basale)
-touch sensation
-sensory nerve endings
corneum
dead anucleated cells
-thickened cell membrane and cytoplasm filled w keratin
-20-30 layers
stratum spinosum
also has desmosomes (membrane linked by filaments)
stratum lucidum
palms and soles of feet and lips (thick skin) and fingertips
-clear flat dead cells with keratin 3-5 layers
flaggrin
protein that cross links keratin
dark skin
more melanosomes
receptors in the dermis
-free nerve endings, merkel disks, krause, meissner, pacini, ruffini
ruffini
heat
pacini
pressure
meissner
touch
krause
cold
free nerve
pain
-innervate basal
apoptosis
phagocytosis of cell death
corneocytes
terminally differentiated
integument
cutaneous membrane
-16% of body weight
-.5-4mm thick (thick= heel) (thin= eyelid)
keratinization
-replacing viable cells int he stratum basale with keratin protein as the cells move from the deep to the surface
-this is why friction makes a callus (build up of karatinocytes)
dandruff
excess fo karatinized cells
thin skin
all body but the palms, and soles
-hair
thick skin
-hairless (palms and soles)
eumelanin
brown to black
pheomelanin
yellow to red
nevi
birthmark
-chronic lesions
melanoma
cancer of melanocytes
defect on enzyme that makes malanin
albinism
dermis
connective tissue with collagen and elastic fibers
two regions of the dermis
papillary region and reticular region
papillary region
-below the epidermis
-has areolar connective tissue (thin collagen, elastic, dermal papillae)
reticular region
dense irregular connective tissue with collagen and elastic fibers, adipose, hair and nerve and oil/ sweat glands
what region for stretch makrs (striae)
reticular region
dermis functions
prevent dehydration and temp stability but cant heal very well
superficial receptors
merkel, free nerve and meissner/ hair root plexus
deep
pacinian corpuscle
deep wound
dermis wound and into subcutaneous layer
-lose function and develop scar tissue
superficial rule
return to normal function
