Skin Structure Flashcards

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1
Q

Thickest epidermis

A

Palms/soles - 1.5 mm

Eyelid thinnest - .1 mm

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2
Q

Thickest dermis

A

Back 30 to 40x thicker than epi

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3
Q

Where merkel cells are found

A

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

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4
Q

Malpighian layer

A

Stratum spinosum

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5
Q

Skin changes with scratching

A

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

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6
Q

Sites rich in stem cells

A

Deepest portion of rete, especially palmoplantar skin

Hair bulge

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7
Q

Stem cells express high levels of?

A

B1 integrin

*SC have LOW levels of desmosomal proteins like dgl 3

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8
Q

Tonofilament keratin structure

A

Alpha helical coiled coil pattern

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9
Q

Widespread apoptosis occurs in

A

Verrucous phase of IP

Catagen (apoptosis results in involution of the inferior segment)

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10
Q

Where are lamellar granules found

A

Intercellular space btw the granular and cornified cell layer

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11
Q

Pro -> filagrin takes place where

A

Granular layer

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12
Q

Site of melanosome synthesis

A

Golgi

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13
Q

Melanocytes express?

A

Neurotrophic 4 - release downregulated by UVB

TLR - stimulation by bact LPS increases pigmentation

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14
Q

LC cells found where

A

Stratum spinosum

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15
Q

Highest density of LC cells in mouth is where?

A

Vestibule of oral mucosa

Lowest density at sublingual region = immune privilege

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16
Q

Dermal dendritic cell markers

A

Macrophage mannose receptor
CD 36
Factor XIIIa
Chemokine receptor 5

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17
Q

Major component of basal lamina

A

Type IV collagen

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18
Q

Major component of anchoring fibrils

A

Type VII collagen

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19
Q

Adnexa are derived from

A

Ectodermal, from downgrowths of the epidermis

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20
Q

Critical for hair development

A

Hedgehog signaling by the signal transducer smoothened

21
Q

Eccrine unit derived from

A

Downgrowths of epidermis

22
Q

Eccrine unit structure

A

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)

23
Q

Eccrine is under what control

A

Cholinergic

*VIP may also stimulate

24
Q

Apocrine derived from

A

Outgrowths of the infundibular or upper portion of the follicle

25
Q

Apocrine structure

A

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

26
Q

Found in apocrine secretion

A

Protein, carb, ammonia, lipid, iron

27
Q

Apocrine

A

Adrenergic

Excretion is episodic although secretion is continuous

28
Q

Upper portion of the follicle forms what

A

Sebaceous gland

29
Q

Lower portion of the follicle forms

A

Attachment for arector pili

30
Q

Signaling by what is essential for hair follicle development

A

Noggin and ectodysplasin A

31
Q

Hair shaft and ORS produced by what

A

Matrix

32
Q

Rate of hair growth

A

.37 mm/ day

33
Q

What happens to hair in pregnancy

A

Prolonged telogen - released after delivery

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

34
Q

Chemo affect on hair

A

Alter mitosis activity on anagen hairs causing a tapered fracture

35
Q

White people hair shape

A

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

Black is opposite

36
Q

Where are sebaceous glands not found

A

Palms and soles

37
Q

Sebocytes express what R

A

Histamine, antihistamines may decrease sebum

38
Q

Rate of nail growth

A

.1 mm/ d

39
Q

Origin of dermis

A

Mesodermal (except nerves)

40
Q

Critical for ventral vs dorsal dermal differentiation

A

Want/beta catenin signaling

41
Q

Major component of dermis

A

Type I collagen

42
Q

Type VII collagen produced by

A

Keratinocytes

43
Q

Hyaluronic acid

A

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

44
Q

Vascular smooth muscle

A

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

45
Q

Meissners corpuscles located where

A

Dermal papillae

46
Q

Mucocutaneous end organs

A

Papillary dermis at Mucocutaneous jxns

47
Q

Histamine evoked itch transmitted by

A

Slow conducting unmyelinated C fibers

48
Q

Infantile digital fibroma stains

A

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