Structure and Function Lecture Qs Part 1

Question 1

collagen of cartilage

Answer 1

collagen 2

Question 2

merkel cell stains

Answer 2

neuron specific enolase (NSE)
chromogranin
synaptophysin
VIP
CK20

Question 3

neurosecretory granules in cytoplasm. tumor cells stain with neuron-specific enolase. which cell am i?

Answer 3

merkel cell

Question 4

cross-linkage of involucrin into the stratum corneum results from the activity of which enzyme

Answer 4

epidermal transglutaminase

Question 5

factor XIIIa and CD34 stain what type of cell? which stains DFs? which stains DFSP?

Answer 5

dendritic cells
13a in DF
CD34 in DFSP

Question 6

glycosaminoglycans and proteoglycans make up what?

Answer 6

ground substance

proteoglycan = macromolecule with core protein (versican and perlecan) and attached GAGs (hyaluronic acid)

Question 7

name two proteoglycans

Answer 7

versican and perlecan

Question 8

describe the difference between oxytalin and elaunin microfibrils

Answer 8

oxytalin fibers run perpendicular and insert into BM from papillary dermis
elaunin fibers run parallel in reticular dermis and have low elastin content

Question 9

what unique amino acids make up elastin

Answer 9

desmosine and isodesmosine

Question 10

what stimulates versus inhibits collagen production

Answer 10

stimulating: ascorbic acid, TGF-beta, retinoic acid
inhibiting: IL-1, glucocorticoids, interferon alpha, TNF alpha, d-penicillamine, minoxidil

Question 11

cross-linking of collagen molecules requires what cofactor

Answer 11

copper is required by catalyzed lysyl oxidase

Question 12

collagen hydroxylation is dependent on what cofactor

Answer 12

vitamin c is required by prolyl and lysyl hydroxylase

Question 13

the dermis is made up of which collagens? which are the ‘adult’ and ‘fetal’ collagens

Answer 13

collagens 1, 3, 5.
type 1 (85%) adult
type 3 (10%) fetal
type 5 (5%)

Question 14

name the different eyelid glands and what type they are (apocrine or sebaceous)

Answer 14

moll (apocrine)
meibomian (sebaceous, open into follicle)
zeiss (sebaceous, don’t open into follicle)

Question 15

how does hair growth on the head differ from that on the body?

Answer 15

compared to scalp (2-6 yrs), most areas of body have SHORTER ANAGEN phase and loner telogen phase

Question 16

name the three phases of hair growth and how long they last

Answer 16

anagen (3-5 years, active phase)
catagen (3 wks, involution phase)
telogen (3 months, resting phase)

Question 17

what is the name for the area with the widest diameter of the hair bulb

Answer 17

line of auber
bulk of mitotic activity that gives rise to the hair and the IRS.
ORS occurs below this level

Question 18

hair follicles develop during what weeks of gestation? where on the body first?

Answer 18

9-12 weeks
head, then cephalad –> caudal
ectodysplasin A and noggin are essential for development

Question 19

apocrine glands: what type of secretion? contains? innervation?

Answer 19

decapitation
protein, carbs, lipids, ammonia, iron, sialomucin.
adrenergic

Question 20

eccrine glands: what type of secretion? innervation?

Answer 20

merocrine

sympathetic cholinergic thru postganglionic C fiber production of acetylcholine

Question 21

the epidermal appendages develop between weeks __ of gestation. in what order

Answer 21

weeks 18-24

hair, sebaceous, eccrine, apocrine

Question 22

name the components of the lamina densa. there are 7

Answer 22

type 4 collagen
laminin 5 (laminin 332, epiligrin)
laminin 6
laminin 10
nidogen (entactin)
fibulin
perlecan

Question 23

what components traverse the lamina lucida? there are 3

Answer 23

laminin 5 (laminin 332, epiligrin)
anchoring filaments
BPAg 2 (BP180, collagen 17)

Question 24

anchoring fibrils are made of what collagen?

Answer 24

collagen 7

Question 25

the keratin intermediate filaments in the basal layer are made up of what keratins

Answer 25

K5, K14

Question 26

what collagen makes up the lamina densa

Answer 26

collagen 4

Question 27

what virus is implicated in Merkel cell carcinoma

Answer 27

polyomavirus

Question 28

what type of cell is the merkel cell? what is the stain to remember?

Answer 28

neuroendocrine cell with slow adapting type I mechanoreceptors
CK20

Question 29

UV exposure increases or decreases Langerhans cell population?

Answer 29

decreases

Question 30

where are langerhans cells derived? what is their main function? main marker?

Answer 30

mesoderm/bone marrow derived.
function in antigen presentation via MHC II, secrete IL-12
main marker is CD1a

Question 31

what receptor/gene is the most important regulator of melanin production

Answer 31

MCR1 receptor (melanocortin 1)
loss-of-function mutation in redheads

Question 32

how do melanosomes in darker skin compare to those in lighter skin

Answer 32

darker skin melanosomes increased in size and number and are more singly dispersed. slow degradation

Question 33

why do melanocytes have a surrounding clear halo in the basal layer?

Answer 33

lack tonofilaments, therefore cannot form desmosomal attachments with keratinocytes

Question 34

each melanocyte interacts with approximately how many keratinocytes

Answer 34

36 keratinocytes = epidermal melanin unit

Question 35

melanocytes are derived from

Answer 35

neural crest cells

Question 36

name the desmosomal cadherins. there are 4

Answer 36

desmoglein
desmocollin
desmoplakin
plakoglobin

Question 37

what are cadherins

Answer 37

Calcium dependent adhesion molecules

Question 38

name the corresponding connexins to the following gap junctions: GJB2, GJB3 & 4, GJB6

Answer 38

GJB2: Connexin 26
GJB3 & 4: Connexin 31 and 30.3
GJB6: Connexin 30

Question 39

what are gap junctions composed of and what do they do?

Answer 39

GJ are composed of connexons
connexon is formed from six connexin molecules
allow for electric and metabolic coupling among cells

Question 40

what are the 6 desmosomal plaque proteins

Answer 40

desmoplakins 1 & 2 (mediate attachement of keratins to plaque)
desmocalmin (calcium regulation)
band 6 protein
plakoglobin (mediates attachement of keratin to plaque)