Pre-Class Dermopathology

Question 1

what is the function of skin?

Answer 1

1. barrier to water loss
2. protection from UV exposure/mechanical injury
3. immune function
4. vitamin D production
5. shock absorber

Question 2

what is the epidermis derived from embryologically?

Answer 2

ectoderm

Question 3

what are melanocytes derived from embryologically?

Answer 3

neural crest

Question 4

where are melanocytes found in the skin?

Answer 4

basal layer

Question 5

what is the function of melanocytes?

Answer 5

1. produce melanin pigment
2. protection from UV radiation

melanin is transferred from 1 melanocyte to numerous keratinocytes via dendrites

Question 6

what are Merkel cells?

Answer 6

functions as a slow-adapting touch receptor

directly connected to keratinocytes

Question 7

what is the function of eccrine glands?

Answer 7

temperature regulation

Question 8

what is the dermis made up of?

Answer 8

1. collagen (type I is most common)
2. elastic fibers
3. extracellular matrix
4. blood vessels
5. smooth and skeletal muscle
6. peripheral nerves
7. was cells, histiocytes
8. dermal dendrocytes which help with wound healing

Question 9

what is subcutaneous tissue composed of?

Answer 9

1. adipocytes

2. capillaries

Question 10

what is a first degree burn?

Answer 10

loss of superficial epidermis

no scarring; complete regeneration

redness and tenderness

ex. sunburn

Question 11

what is a 2nd degree burn?

Answer 11

loss of entire epidermis and some dermis

some scarring, some regeneration

usually blisters

Question 12

what is a 3rd degree burn?

Answer 12

loss of dermis and appendages

scarring, no regeneration

not painful because loss of pain receptors

Question 13

what parts of the skin are considered appendages?

Answer 13

1. follicles (hair)
2. sebaceous glands
3. eccrine glands
4. apocrine glands
5. nails

Question 14

what is acanthosis?

Answer 14

increased thickness of the spinous layer of the epithelium

Question 15

what is hyperplasia?

Answer 15

increased number of cells in the spinous layer of the epithelium

Question 16

what is papillomatosis?

Answer 16

skin surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae

Question 17

what changes happen in the epidermis as you age?

Answer 17

1. atrophy of the epidermis –> increased shear force injury –> senile purpura
2. decreased langerhans cells –> decreased immunity –> increased risk of malignancy

Question 18

what changes happen in the dermis as you age?

Answer 18

decreased collagen combined with abni elastin production = decreased elasticity and flexibility

Question 19

what are the effects of UV radiation on the epidermis?

Answer 19

1. keratinocytes

causes DNA damage (formation of pyrimadine dimers) –> dysplasia and malignancy

2. melanocytes

induces proliferation for melanin production which over time can lead to melanoma

3. langerhans cells

decreased function leads to decreased immunity

Question 20

what are the effects of UV radiation on the dermis?

Answer 20

abnormal elastin production leads to solar (actinic) elastosis

this is an an accumulation of abnormal elastin in the dermis

Question 21

what is macule?

Answer 21

flat, less than 1 cm

Question 22

what is a patch?

Answer 22

flat, greater than 1 cm

Question 23

what is a papule?

Answer 23

elevated, solid lesion

less than 1 cm

Question 24

what is a plaque?

Answer 24

elevated, solid lesion

greater than 1 cm

Question 25

what is a nodule?

Answer 25

solid, palpable greater than 1 cm

Question 26

what is a scale?

Answer 26

dry, plate-like excrescences due to imperfect maturation and cornification

Question 27

what is a wheal?

Answer 27

transient, pruritic, edematous and erythematous due to dermal edema

Question 28

what is a vesicle?

Answer 28

fluid filled blister less than 1 cm

Question 29

what is a bulla?

Answer 29

fluid filled blister greater than 1 cm

Question 30

what is atrophy of the skin?

Answer 30

thinning of the epidermis or dermis loss of rete ridge pattern Ex: Lichen sclerosus

Question 31

what is lichenification?

Answer 31

thickened, roughened skin prominent skin markings due to chronic rubbing

Question 32

what does hyperkeratosis mean?

Answer 32

thicker stratum corneum

Question 33

what does orthokeratosis mean?

Answer 33

basketweave stratum corneum

Question 34

what does parakeratosis mean?

Answer 34

retained nuclei in stratum corneum

Question 35

what is acantholysis?

Answer 35

separation of epidermal cells = loss of desmosomes acantholysis is the loss of intercellular connections, such as desmosomes, resulting in loss of cohesion between keratinocytes, seen in diseases such as pemphigus vulgaris --> it is absent in bullous pemphigoid, making it useful for differential diagnosis

Question 36

what is spongiosis?

Answer 36

increased intercellular edema

Question 37

what is dyskeratosis?

Answer 37

premature keratinization below the granular layer