Structure and Function Lecture Qs Part 1 Flashcards
collagen of cartilage
collagen 2
merkel cell stains
neuron specific enolase (NSE) chromogranin synaptophysin VIP CK20
neurosecretory granules in cytoplasm. tumor cells stain with neuron-specific enolase. which cell am i?
merkel cell
cross-linkage of involucrin into the stratum corneum results from the activity of which enzyme
epidermal transglutaminase
factor XIIIa and CD34 stain what type of cell? which stains DFs? which stains DFSP?
dendritic cells
13a in DF
CD34 in DFSP
glycosaminoglycans and proteoglycans make up what?
ground substance
proteoglycan = macromolecule with core protein (versican and perlecan) and attached GAGs (hyaluronic acid)
name two proteoglycans
versican and perlecan
describe the difference between oxytalin and elaunin microfibrils
oxytalin fibers run perpendicular and insert into BM from papillary dermis
elaunin fibers run parallel in reticular dermis and have low elastin content
what unique amino acids make up elastin
desmosine and isodesmosine
what stimulates versus inhibits collagen production
stimulating: ascorbic acid, TGF-beta, retinoic acid
inhibiting: IL-1, glucocorticoids, interferon alpha, TNF alpha, d-penicillamine, minoxidil
cross-linking of collagen molecules requires what cofactor
copper is required by catalyzed lysyl oxidase
collagen hydroxylation is dependent on what cofactor
vitamin c is required by prolyl and lysyl hydroxylase
the dermis is made up of which collagens? which are the ‘adult’ and ‘fetal’ collagens
collagens 1, 3, 5. type 1 (85%) adult type 3 (10%) fetal type 5 (5%)
name the different eyelid glands and what type they are (apocrine or sebaceous)
moll (apocrine)
meibomian (sebaceous, open into follicle)
zeiss (sebaceous, don’t open into follicle)
how does hair growth on the head differ from that on the body?
compared to scalp (2-6 yrs), most areas of body have SHORTER ANAGEN phase and loner telogen phase
name the three phases of hair growth and how long they last
anagen (3-5 years, active phase)
catagen (3 wks, involution phase)
telogen (3 months, resting phase)
what is the name for the area with the widest diameter of the hair bulb
line of auber
bulk of mitotic activity that gives rise to the hair and the IRS.
ORS occurs below this level
hair follicles develop during what weeks of gestation? where on the body first?
9-12 weeks
head, then cephalad –> caudal
ectodysplasin A and noggin are essential for development
apocrine glands: what type of secretion? contains? innervation?
decapitation
protein, carbs, lipids, ammonia, iron, sialomucin.
adrenergic
eccrine glands: what type of secretion? innervation?
merocrine
sympathetic cholinergic thru postganglionic C fiber production of acetylcholine
the epidermal appendages develop between weeks __ of gestation. in what order
weeks 18-24
hair, sebaceous, eccrine, apocrine
name the components of the lamina densa. there are 7
type 4 collagen laminin 5 (laminin 332, epiligrin) laminin 6 laminin 10 nidogen (entactin) fibulin perlecan
what components traverse the lamina lucida? there are 3
laminin 5 (laminin 332, epiligrin) anchoring filaments BPAg 2 (BP180, collagen 17)
anchoring fibrils are made of what collagen?
collagen 7
the keratin intermediate filaments in the basal layer are made up of what keratins
K5, K14
what collagen makes up the lamina densa
collagen 4
what virus is implicated in Merkel cell carcinoma
polyomavirus
what type of cell is the merkel cell? what is the stain to remember?
neuroendocrine cell with slow adapting type I mechanoreceptors
CK20
UV exposure increases or decreases Langerhans cell population?
decreases
where are langerhans cells derived? what is their main function? main marker?
mesoderm/bone marrow derived.
function in antigen presentation via MHC II, secrete IL-12
main marker is CD1a
what receptor/gene is the most important regulator of melanin production
MCR1 receptor (melanocortin 1) loss-of-function mutation in redheads
how do melanosomes in darker skin compare to those in lighter skin
darker skin melanosomes increased in size and number and are more singly dispersed. slow degradation
why do melanocytes have a surrounding clear halo in the basal layer?
lack tonofilaments, therefore cannot form desmosomal attachments with keratinocytes
each melanocyte interacts with approximately how many keratinocytes
36 keratinocytes = epidermal melanin unit
melanocytes are derived from
neural crest cells
name the desmosomal cadherins. there are 4
desmoglein
desmocollin
desmoplakin
plakoglobin
what are cadherins
Calcium dependent adhesion molecules
name the corresponding connexins to the following gap junctions: GJB2, GJB3 & 4, GJB6
GJB2: Connexin 26
GJB3 & 4: Connexin 31 and 30.3
GJB6: Connexin 30
what are gap junctions composed of and what do they do?
GJ are composed of connexons
connexon is formed from six connexin molecules
allow for electric and metabolic coupling among cells
what are the 6 desmosomal plaque proteins
desmoplakins 1 & 2 (mediate attachement of keratins to plaque)
desmocalmin (calcium regulation)
band 6 protein
plakoglobin (mediates attachement of keratin to plaque)
