Common Terms

Question 1

epidermis

Answer 1

barrier, protection, wound healing
melanin
keratinocytes, melanocytes, Langerhans cells, Merkel cells
SELF-RENEWING: sheds every 28+ days
stem cells in basal layer, differentiate as move up, shed at surface

Question 2

dermis

Answer 2

structural and nutritional (vascular) support, innervation
fibroblasts, collagen, elastic, blood vessels, nerve endings
hair follicles, sweat and oil glands

Question 3

Why is intact skin a poor host for organisms?

Answer 3

dry
impermeable
sheds
no vessels

Question 4

desmosome

Answer 4

connects keratinocytes to one another

Ab: PEMPHIGUS VULGARIS

Question 5

hemi-desmosome

Answer 5

basal cells of epidermis adhere to basement membrane (dermis-epidermis)
Ab: BULLOUS PEMPHIGOID

Question 6

melanin

Answer 6

protects against UV radiation

Question 7

hypohidrotic ectodermal dysplasia

Answer 7

EDAR gene mutation: ectodysplasin A receptor

abnormal hair follicles, sweat glands, teeth, unable to regulate temp (OVERHEAT)

Question 8

EDAR

Answer 8

gene for ectodysplasin A receptor: protein for proper interaction between developing ectoderm and mesoderm
HYPOHIDROTIC ECTODERMAL DYSPLASIA

Question 9

What are the 7 functions of skin and examples of their failure?

Answer 9

1. barrier (dehydration, infection)
2. immune (infection, autoimmunity, CA)
3. repair (skin CA, ulcer)
4. regulate temp. (hypo/hyperthermia)
5. circulation (infarction, emboli, vasculitis)
6. communication (itching, insensitivity)
7. photoprotection (CA, photoaging)

Question 10

subcutis

Answer 10

structural, vascular support and innervation
fat, blood vessels, fibrous septae
hair follicle
insulation, energy, protection

Question 11

Four layers of epidermis

Answer 11

surface to BM

1. stratum corneum
2. stratum granulosum
3. stratum spinosum
4. stratum basale

Question 12

stratum basale

Answer 12

source of stem cells

basal cells adhere to dermis through HEMIDESMOSOMES

Question 13

adherens junctions

Answer 13

links actin filaments keratinocyte-keritinocyte

Question 14

gap junctions

Answer 14

connexin proteins

cell-cell communication

Question 15

stratum spinosum

Answer 15

cells stop dividing and start terminal differentiation

lipids: lamellar granules
spiny: visible DESMOSOMES

Question 16

stratum granulosum

Answer 16

intracellular keratohyaline granules: includes profilaggrin

lipids in lamellar granules secreted into intercellular space to form water barrier

Question 17

stratum corneum

Answer 17

nuclei and organelles degenerate and cells flatten
profillafrin processed into FILAGGRIN: keeps water in cells
KERATIN

Question 18

filaggrin

Answer 18

keeps water in cells

Question 19

keratin

Answer 19

structural cytoskeletal proteins in hair, skin, nails
combine with filaggrin in stratum corneum into microfibrils (INTERMEDIATE FILAMENTS) that create protective layer
lots of CYSTEINE (sulfur containing)

Question 20

melanocytes

Answer 20

pigment producing dendritic cells
derived from NEURAL CREST
live along basal cell
produce melanin and transfers to keratinocytes: radiation-absorbing pigment

Question 21

Langerhans cells

Answer 21

dendritic cells in mid-epidermis
major immunology player in skin
recognize abnormal antigens in skin and process them, then present to lymphocytes in lymph nodes
allergic rxn, tumor surveillance

Question 22

Merkel cell

Answer 22

epidermis
associated with light touch
can develop into malignant tumor

Question 23

fibroblast

Answer 23

dermis
mesenchymal origin
synthesis and degradation of CT proteins: collagen, elastin
wound healing, scar formation

Question 24

mast cells

Answer 24

dermis
histamine and heparin granules
triggered by IgE
allergic rxn, wound healing
WHEAL and FLARE

Question 25

sebaceous gland

Answer 25

oil gland associated with hair follicle

Question 26

pilosebaeous unit

Answer 26

hair follicle and sebaceous gland/apocrine gland and arrestor pili muscle

Question 27

apocrine gland

Answer 27

sweat glands in axilla and anogenital skin)

Question 28

eccrine sweat glands

Answer 28

true sweat glands throughout body, not associated with hair follicle regulate temperature by evaporation of cooling sweat

Question 29

macule

Answer 29

circumscribed area of skin differing in color or texture from surrounding skin ex: freckles, flat nevi, cafe au lait, non palpable purport, petechiae, and ecchymoses

Question 30

patch

Answer 30

macule measuring greater than 2 cm in diameter

Question 31

papule

Answer 31

solid palpable elevation of skin measuring less than 0.5 cm in diameter

Question 32

nodule

Answer 32

solid mass of skin seen/palpated measuring greater than 0.5 cm in diameter

Question 33

plaque

Answer 33

elevated area of skin measuring 2cm or more in diameter

Question 34

wheal

Answer 34

elevated, compressible papule or plaque resulting from dermal edema hives

Question 35

vesicle

Answer 35

circumscribed, fluid filled elevation of skin measuring less than 0.5 cm in diameter ex: chicken pox, herpes simplex

Question 36

bulla

Answer 36

circumscribed, fluid filled elevation of skin measuring greater than 0.5 cm in diameter blisters

Question 37

erosion

Answer 37

loss of epidermis that heals without scarring | eruption of vesicle or bullae

Question 38

ulcer

Answer 38

loss of epidermis and dermis as result of sloughing necrotic tissue

Question 39

petechiae

Answer 39

small, punctate hemorrhagic spot measuring 1-2 mm in diameter

Question 40

ecchymosis

Answer 40

macular hemorrhagic spot measuring greater than 2 mm in diameter bruises

Question 41

purpura

Answer 41

discoloration of the skin or mucosal membranes by extravasated blood