Common Terms Flashcards
epidermis
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
dermis
structural and nutritional (vascular) support, innervation
fibroblasts, collagen, elastic, blood vessels, nerve endings
hair follicles, sweat and oil glands
Why is intact skin a poor host for organisms?
dry
impermeable
sheds
no vessels
desmosome
connects keratinocytes to one another
Ab: PEMPHIGUS VULGARIS
hemi-desmosome
basal cells of epidermis adhere to basement membrane (dermis-epidermis)
Ab: BULLOUS PEMPHIGOID
melanin
protects against UV radiation
hypohidrotic ectodermal dysplasia
EDAR gene mutation: ectodysplasin A receptor
abnormal hair follicles, sweat glands, teeth, unable to regulate temp (OVERHEAT)
EDAR
gene for ectodysplasin A receptor: protein for proper interaction between developing ectoderm and mesoderm
HYPOHIDROTIC ECTODERMAL DYSPLASIA
What are the 7 functions of skin and examples of their failure?
- barrier (dehydration, infection)
- immune (infection, autoimmunity, CA)
- repair (skin CA, ulcer)
- regulate temp. (hypo/hyperthermia)
- circulation (infarction, emboli, vasculitis)
- communication (itching, insensitivity)
- photoprotection (CA, photoaging)
subcutis
structural, vascular support and innervation
fat, blood vessels, fibrous septae
hair follicle
insulation, energy, protection
Four layers of epidermis
surface to BM
- stratum corneum
- stratum granulosum
- stratum spinosum
- stratum basale
stratum basale
source of stem cells
basal cells adhere to dermis through HEMIDESMOSOMES
adherens junctions
links actin filaments keratinocyte-keritinocyte
gap junctions
connexin proteins
cell-cell communication
stratum spinosum
cells stop dividing and start terminal differentiation
lipids: lamellar granules
spiny: visible DESMOSOMES
stratum granulosum
intracellular keratohyaline granules: includes profilaggrin
lipids in lamellar granules secreted into intercellular space to form water barrier
stratum corneum
nuclei and organelles degenerate and cells flatten
profillafrin processed into FILAGGRIN: keeps water in cells
KERATIN
filaggrin
keeps water in cells
keratin
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)
melanocytes
pigment producing dendritic cells
derived from NEURAL CREST
live along basal cell
produce melanin and transfers to keratinocytes: radiation-absorbing pigment
Langerhans cells
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
Merkel cell
epidermis
associated with light touch
can develop into malignant tumor
fibroblast
dermis
mesenchymal origin
synthesis and degradation of CT proteins: collagen, elastin
wound healing, scar formation
mast cells
dermis histamine and heparin granules triggered by IgE allergic rxn, wound healing WHEAL and FLARE
sebaceous gland
oil gland associated with hair follicle
pilosebaeous unit
hair follicle and sebaceous gland/apocrine gland and arrestor pili muscle
apocrine gland
sweat glands in axilla and anogenital skin)
eccrine sweat glands
true sweat glands
throughout body, not associated with hair follicle
regulate temperature by evaporation of cooling sweat
macule
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
patch
macule measuring greater than 2 cm in diameter
papule
solid palpable elevation of skin measuring less than 0.5 cm in diameter
nodule
solid mass of skin seen/palpated measuring greater than 0.5 cm in diameter
plaque
elevated area of skin measuring 2cm or more in diameter
wheal
elevated, compressible papule or plaque resulting from dermal edema
hives
vesicle
circumscribed, fluid filled elevation of skin measuring less than 0.5 cm in diameter
ex: chicken pox, herpes simplex
bulla
circumscribed, fluid filled elevation of skin measuring greater than 0.5 cm in diameter
blisters
erosion
loss of epidermis that heals without scarring
eruption of vesicle or bullae
ulcer
loss of epidermis and dermis as result of sloughing necrotic tissue
petechiae
small, punctate hemorrhagic spot measuring 1-2 mm in diameter
ecchymosis
macular hemorrhagic spot measuring greater than 2 mm in diameter
bruises
purpura
discoloration of the skin or mucosal membranes by extravasated blood
