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Derm > Week 1 > Flashcards

Week 1 Flashcards

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Dermatology Board Prep flashcards
1
Q

Which germ layers do epidermis and the dermis come from?

A

ectoderm cells - epidermis

mesoderm - dermis

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2
Q

What type of epithelium is the epidermis?

A

stratified epithelium

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3
Q

What are the layers of the skin?

A 
epidermis
keratin layer
granular layer
prickle cell layer 
basal layer
dermis
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4
Q

Where are melanocytes found in the skin and where did they migrate there from?

A

basal epidermis or in the matrix of hair during embryological development - migrated from neural crest

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5
Q

How is the neural crest formed?

A

during the formation of the neural tube (precursor to spinal cord) embryological cells are pinched off = neural crest

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6
Q

What happens during epidermis differentiation? How long does it take?

A

Keratinocytes migrate from the basement membrane to the surface of the epidermis = continuous regeneration of the epidermis.
Takes 28 days.

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7
Q

How many weeks into foetal development does the epidermis comprise 4 layers?

A

16 weeks

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8
Q 
Name the layer of epidermis:
one cell thick
small cuboidal 
lots of intermediate filaments (keratin)
highly metabolically active
A

basal layer

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9
Q

What are corneocytes and which epidermis layer has them?

A

overlapping non-nucleated remnants of terminally differentiated keratinocytes

therefore found in keratin layer

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10
Q

What are the features of the keratin layer?

A 
corneocytes 
insoluble cornified envelope
80% keratin & filaggrin
lamellar granules release lipid
tight waterproof barrier
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11
Q 
Which layer:
2-3 layers of flatter cells
large keratohyalin granules
Odland (lamellar) bodies 
high lipid content
cell nuclei lost
A

granular layer

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12
Q

Which layer is the origin of the ‘cornified envelope’?

A

granular layer - granules burst and release contents in layer, left over lipids and proteins come together to form an evelope

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13
Q

Which layer:
larger polyhedral cells
lots of desmosomes
intermediate filaments (connect desmosomes)

A

prickle cell layer

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14
Q

Describe melanocytes.

A

melanin (pigment) producing dendritic cells
contain organelles called melanosomes
form protective cap over nucleus

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15
Q

Which chemical conversion occurs in melanocytes?

A

tyrosine to melanin pigment;

eumelanin and phaeomelanin

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16
Q

Which type of melanin pigment is brown/black?

A

eumelanin

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17
Q

which type of melanin pigment is red/yellow?

A

phaeomelanin

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18
Q

What is the function of melanin and melanin granules?

A

melanin absorbs light and therefore a natural density filter (sun cream)

full melanosomes (‘melanin granules’) are transferred to adjacent keratinocytes via dendrites (bud off)

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19
Q

What is the correct name for the smooth muscle fibres attached to hair follicles?

A

arrector pili muscles

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20
Q

What type of unit is a hair follicle?

A

pilosebaceous unit

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21
Q

What is the name for the ‘natural moisturiser’ that is continuously secreted? Which gland secretes it?

A

sebum from sebaceous gland

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22
Q

What are the 3 phases of growth?

A

angen
catagen
telogen

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23
Q

Angen phase takes place during which years of life and producing what percentage of hairs?

A

3-7 years, 90%

angen = growing

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24
Q

Catagen phase occurs for how long?

A

3-4 weeks, 10% hairs

catagen = involuting

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25
Q

Telogen phase also known as what phase? Occurs when?

A

shedding phase, each day <1% hairs

telogen = resting

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26
Q

What is the growth rate of nails?

A

0.1mm per day

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27
Q

Toe nails grow faster than finger nails?

A

False, fingers > toes

summer > winter

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28
Q

Nail plate sits on top of ?

A

nail bed

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29
Q

White area at base of nail plate?

A

lunula

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30
Q

What secures the free nail?

A

hyponychium

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31
Q

What cellular processes occur in the nail matrix?

A

cells divide and then produce hard keratin

32
Q

What is a cuticle?

A

an extension of free skin fold covering the nail root

33
Q

What is the interface between the epidermis and the dermis?

A

the dermo-epidermal junction

34
Q

What are the key roles of the DEJ?

A

support, anchorage, adhesion, growth and differentiation of basal layer
semi-permeable membrane acting as barrier and filter

35
Q

Name the condition where antibodies are formed against the DEJ.

A

bullous pemphigoid

36
Q

Babies with a ‘mitten deformity’

A

epidermolysis bullosa

37
Q

Rash and large itchy blisters found on the arms, legs and middle of body…

A

bullous pemphigoid

38
Q

A group of genetic skin disorders that make skin very fragile - any trauma or friction to the skin can cause painful blisters…

A

epidermolysis bullosa

39
Q

What do fibroblasts do?

A

collagen and extracellular matrix synthesis

40
Q

Where are retentions ridges found and what is their role?

A

papillary dermis (top layer) - epithelial extensions that project into the underlying areolar connective tissue

41
Q

What is the layer of dermis below papillary dermis?

A

reticular dermis - dense irregular connective tissue featuring densely packed collagen fibres.
Primary location of dermal elastic fibres

42
Q

What is elastin?

A

the protein which allows skin to be pinched and return back to its normal position

43
Q

Name the sweat glands active only upon puberty. Where are they found and what do they secrete? Which hormone are they dependent on?

A

Apocrine sweat glands
develop as part of pilosebaceous unit - produce oily fluid -> odour after bacterial decomposition
axillae, nipples, perineum
androgen dependent

44
Q

What are holocene secretions?

A

produced in cytoplasm and released by the rupture of the plasma membrane which destroys the cell and results in the secretion of the product into the lumen.

45
Q

Which sweat gland utilises holocrine secretions? Where are they found & what is their function?

A

sebaceous glands - holocrine secretions opening into pillary canal
widely distributed - largest glands in face and chest
lobulated masses in dermis which secrete sebum into hair follicle to coat hair and skin
control moisture loss, protection from fungal infection

46
Q

Where are sebaceous glands not found?

A

palms and sole skin

47
Q

When are sebaceous glands dormant?

A

pre-puberty (hormone sensitive)

48
Q

Which sweat glands are found on the whole skin surface, except lips & genitalia?

A

eccrine sweat glands

found on palms, soles and axillae in particular

49
Q

What is the stimulation of eccrine sweat glands? What are their functions?

A

sympathetic cholinergic nerve supply - mental, thermal & gustatory stimulation

Coiled tubular structure which regulate heat & salt loss; cooling by evaporation; moisten palms/soles to aid grip

50
Q

Which sweat gland has the best filtration rate?

A

eccrine
ultrafiltration: can be >10L per day
NaCl + HCO3 reabsorbed - hypotonic fluid

51
Q

Name conditions that occur if the skin barrier function is lost.

A 
dehydration
hypoalbuminaemia
steroid-sulphatase deficiency x-linked ichthyosis
cumulative irritant hand dermatitis
ulcer following compound fracture
52
Q

Erosions on fingertips; redness and scaling in-between fingers - type IV hypersensitivity

A

cumulative irritant hand dermatitis

53
Q

condition characterised by loss of barrier function due to no normal lipids present in keratin layer…

A

steroid-sulphatase deficiency x-linked ichthyosis

54
Q

Which sweat gland type is triggered in thermoregulation?

A

eccrine

55
Q

What cell types are found in the dermis and involved in sensation?

A

pacinian corpuscles

meissner’s corpuscles

56
Q

Which structure is involved in deep pressure sensation?

A

pacinian corpuscles

57
Q

Which structure is used for tactile sensation?

A

messier’s corpuscles

58
Q

Pain is detected by free nerve endings found in which layer of skin?

A

basal layer of epidermis

59
Q

Define stigma.

A

the term describes the situation of an individual who is disqualified from full social acceptance

60
Q

Skin is metabolically active in which metabolisms?

A

vitamin D and thyroid hormone

61
Q

Skin absorbs which frequency of UV light to cause which conversion in vitamin D synthesis?

A

290-320nm

cholecalciferol (7-dehydrocholesterol) converted to vitamin D3

62
Q

Vitamin D3 is stored by the liver as which compound?

A

hydroxycholecalciferol

63
Q

What conversion does the kidneys do in vitamin D synthesis?

A

hydroxycholecalciferol -> 1,25-dihydroxycholecalciferol

64
Q

What is the effect of 1,25-hydroxycholecalciferol on the bowel?

A

increased calcium absorption

65
Q

What is the role of skin in thyroid hormone metabolism?

A

80% of the conversion of T4 -> T3 occurs in peripheral (to thyroid) tissues including the skin;
remaining 20% occurs in thyroid gland

66
Q

What is PVL?

A

Panton Valentine Leukocidin is a cytotoxin associated with highly virulent strains of Staph aureus causing necrolytic skin infections by directly killing leucocytes.

67
Q

Which virulence factor causes damage to the host directly?

A

Aggressin

68
Q

Which virulence factor enables the organism to invade a host tissue?

A

Invasin

69
Q

Which virulence factors enables binding of the organism to host tissue?

A

Adhesin

70
Q

Which virulence factor enables the organism to avoid host defence mechanisms?

A

Impedin

71
Q

Which virulence factor causes damage to the host indirectly?

A

Modulin

72
Q

3 y/o boy presents on sunny day, mother reports crying & rubbing skin when outside. Skin sometimes red but no rash, clear now. Skin type 1 with few freckles.

A

erythropoietic protoporphyria

73
Q

deficiency of which enzyme causes erythropoietic protoporphyria (EPP)?

A

ferrochelatase

74
Q

What accumulates due to the enzyme deficiency in erythropoietic protoporphyria?

A

protoporphyrin IX in RBCs (erythrocytes), plasma, skin, and liver.

75
Q

What is impaired in acute intermittent porphyria?

A

porphobilinogen - results in acute neurotoxic reaction in many tissues

Derm (7 decks)

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