091614 epidermis Flashcards
layers of epidermis from superficial to deep
stratum corneum
stratum granulosum
stratum spinosum
stratum basale
basal stem cells in the epidermis give rise to keratinocytes how?
divide to form one daughter cell and a transient amplifying cell
transient amplif cell will divide a few more times before it moves up into the stratum spinosum
what layer makes up most of the epidermis
spinous layer
what does the stratum spinosum do?
makes keratin
hemidesmosome
connection btwn basal cell and ECM
has keratin intermediate filaments on intracellular side
what is the importance of the keratin intermediate filaments in the epidermis
they allow for formation of a network through all the keratinocytes
keratin structure
one type I acidic keratin combines with a type II basic keratin to form a heterodimer
heterodimers combine to form tetramers
tetramers are combined to form protofilaments, which then combine to form intermediate filaments
true or false: keratin types vary in different locations in the body
true
what kinds of granules are the stratum granulosum
keratohyalin granules (filaggrin, involucrin, loricrin)
lamellar granules or Odland bodies (ceramides, cholesterol, fatty acids, hydrolytic enzymes)
corneocytes lack what?
nucleus and organelles
how are corneocytes held together
corneodesmosomes
which sites have no stratum corneum
oral, genital, ocular mucosa
which sites have thin cornified layer
face
genitalia
how does stratum corneum shed?
by hydrolytic enzymes that were in the lamellar granules of stratum granulosum
bricks and mortar
corneocytes have this structure
the bricks are the cornified enveloped of proteins
the mortar is the surrounding lipid envelope
pemphigus vulgaris
acquired autoimmune bullous (blisters) disease auto antibodies to desmosomal proteins (desmoglein 1 and 3)
intraepidermal blistering
clinical features of pemphigus vulgaris
flaccid, easily ruptured bullae
oral and mucosal lesions
positive NIkolsky’s sign (fragile epidermis so by rubbing, can expand the erosion)
treatment for pemphigus vulgaris
prednisone
azathioprine
mycophenolate mofetil
rituximab
ichthyosis vulgaris
autosomal dominant genetic condition
mutations in profillaggrin gene (defective filaggrin protein)
1 in 250 ppl affected
clinical features of icthyosis vulgaris
fish scales especially on shins
dry skin
hyperlinear palms
associations of ichthyosis vulgaris
atopic dermatitis
allergic rhinitis
food allergies
asthma
UV-A penetrates what layer of the skin
what does it cause?
dermis
causes tanning and wrinkles
which types of UV light can cause cancer?
both UVA and UVB
MED
minimal erythemia dose, which is the minimum amt of UVB that causes skin redness at 24 hours
