Skin Structure

Question 1

Thickest epidermis

Answer 1

Palms/soles - 1.5 mm

Eyelid thinnest - .1 mm

Question 2

Thickest dermis

Answer 2

Back 30 to 40x thicker than epi

Question 3

Where merkel cells are found

Answer 3

Basal layer of Palms/soles, oral/genital mucosa, nail bed, follicular infundibula

Question 4

Malpighian layer

Answer 4

Stratum spinosum

Question 5

Skin changes with scratching

Answer 5

Thickening of the malpigian and granular layer
Stratum lucidum forms
Histones regulate epidermal differentiation - histone deacetylation suppresses expression of profillagrin

Question 6

Sites rich in stem cells

Answer 6

Deepest portion of rete, especially palmoplantar skin

Hair bulge

Question 7

Stem cells express high levels of?

Answer 7

B1 integrin

*SC have LOW levels of desmosomal proteins like dgl 3

Question 8

Tonofilament keratin structure

Answer 8

Alpha helical coiled coil pattern

Question 9

Widespread apoptosis occurs in

Answer 9

Verrucous phase of IP

Catagen (apoptosis results in involution of the inferior segment)

Question 10

Where are lamellar granules found

Answer 10

Intercellular space btw the granular and cornified cell layer

Question 11

Pro -> filagrin takes place where

Answer 11

Granular layer

Question 12

Site of melanosome synthesis

Answer 12

Golgi

Question 13

Melanocytes express?

Answer 13

Neurotrophic 4 - release downregulated by UVB

TLR - stimulation by bact LPS increases pigmentation

Question 14

LC cells found where

Answer 14

Stratum spinosum

Question 15

Highest density of LC cells in mouth is where?

Answer 15

Vestibule of oral mucosa

Lowest density at sublingual region = immune privilege

Question 16

Dermal dendritic cell markers

Answer 16

Macrophage mannose receptor
CD 36
Factor XIIIa
Chemokine receptor 5

Question 17

Major component of basal lamina

Answer 17

Type IV collagen

Question 18

Major component of anchoring fibrils

Answer 18

Type VII collagen

Question 19

Adnexa are derived from

Answer 19

Ectodermal, from downgrowths of the epidermis

Question 20

Critical for hair development

Answer 20

Hedgehog signaling by the signal transducer smoothened

Question 21

Eccrine unit derived from

Answer 21

Downgrowths of epidermis

Question 22

Eccrine unit structure

Answer 22

Acrosyringium = intaepidermal spiral duct (derived from dermal surface), composed of small polygonal cells with central round nucleus and amphophilic cytoplasm

Straight dermal portion of the duct- composed of double layer of cuboidal cells lined by an eosinophilic cuticle on luminal side

Coiled secretory acinar portion located in fat

Secretory portion - inner layer of epic cells surrounded by myofibroblasts, 2 cell types (pale glycogen rich cells that initiate sweat formation and dark cells which modify sweat)

Question 23

Eccrine is under what control

Answer 23

Cholinergic

*VIP may also stimulate

Question 24

Apocrine derived from

Answer 24

Outgrowths of the infundibular or upper portion of the follicle

Question 25

Apocrine structure

Answer 25

Straight portion - excretory and opens into the infundibular portion of the follicle, composed of a double layer of cuboidal cells Coiled secretory gland - located at the junction of the dermis and subcutaneous fat

Question 26

Found in apocrine secretion

Answer 26

Protein, carb, ammonia, lipid, iron

Question 27

Apocrine

Answer 27

Adrenergic Excretion is episodic although secretion is continuous

Question 28

Upper portion of the follicle forms what

Answer 28

Sebaceous gland

Question 29

Lower portion of the follicle forms

Answer 29

Attachment for arector pili

Question 30

Signaling by what is essential for hair follicle development

Answer 30

Noggin and ectodysplasin A

Question 31

Hair shaft and ORS produced by what

Answer 31

Matrix

Question 32

Rate of hair growth

Answer 32

.37 mm/ day

Question 33

What happens to hair in pregnancy

Answer 33

Prolonged telogen - released after delivery | Retention of increased Anagen hairs - transition to telogen at delivery and released at 2-3 mo

Question 34

Chemo affect on hair

Answer 34

Alter mitosis activity on anagen hairs causing a tapered fracture

Question 35

White people hair shape

Answer 35

Scalp is round while pubic, beard, and eyelashes are oval Black is opposite

Question 36

Where are sebaceous glands not found

Answer 36

Palms and soles

Question 37

Sebocytes express what R

Answer 37

Histamine, antihistamines may decrease sebum

Question 38

Rate of nail growth

Answer 38

.1 mm/ d

Question 39

Origin of dermis

Answer 39

Mesodermal (except nerves)

Question 40

Critical for ventral vs dorsal dermal differentiation

Answer 40

Want/beta catenin signaling

Question 41

Major component of dermis

Answer 41

Type I collagen

Question 42

Type VII collagen produced by

Answer 42

Keratinocytes

Question 43

Hyaluronic acid

Answer 43

Accumulates in pathological states Stains with colloidal iron And with Toludine blue and Alcian blue metachromatically only at higher ph

Question 44

Vascular smooth muscle

Answer 44

Expresses Vimentin instead of desmin ( like most other smooth m.)

Question 45

Meissners corpuscles located where

Answer 45

Dermal papillae

Question 46

Mucocutaneous end organs

Answer 46

Papillary dermis at Mucocutaneous jxns

Question 47

Histamine evoked itch transmitted by

Answer 47

Slow conducting unmyelinated C fibers

Question 48

Infantile digital fibroma stains

Answer 48

PTAH, Masson trichome, calponin, vimentin, desmin smooth m. Actin