091714 adnexal structures Flashcards
infundibulum
from sebaceous gland to top of epidermis
isthmus
from top of erector pili muscle to top of sebaceous gland
inferior segment of hair
from bottom of hair to erector pili muscle
what contains rapidly dividing cells in the hair?
matrix
what are the type of pilosebaceous units?
lanugo (fetal)
vellus (fine)
terminal (coarse)
how do sebaceous glands produce sebum (through what kind of secretion)?
holocrine secretion
when is hair shed (what phase)?
telogen phase
telogen effluvium
stressor results in greater proportion of hair follicles entering telogen phase
occurs about 3 months after event
alopecia areata
autoimmune condition
smooth patches of complete alopecia
nail pits (indentations in nail plate) may occur
how is alopecia areata different from tinea capitis?
no scaling in alopecia areata
eccrine sweat glands
palms and soles
what are eccrine sweat glands innervated by
sympathetic fibers
apocrine sweat glands
sweaty and smelly
in axillae, anogenital, periumbilical, areolae, border of lips
strcture of eccrine sweat gland
goes directly to surface of skin (the duct)
structure of apocrine sweat gland
inserts into hair follicle
fxn of apocrine sweat glands
unclear
fxn of eccrine sweat glands
thermoregulation
maintenance of electrolyte balance
maintenance of moist stratum corneum to facilitate tactile skills
what are the disorders of the pilosebaceous unit
acne vulgaris
acne rosacea
tinea versicolor
comedo formation
plugging of hair follicles
what causes an inflam response in acne vulgaris?
when the plugged follicles (comedo formation) rupture, causing inflam to the extruded keratin and sebum
what role does Propionibacterium acnes play in acne vulgaris
found deep within the follicle and releases enzymes that promote follicular rupture
also stimulates release of proinflammatory mediators leading to neutrophil recruitment and Th1 responses
how do hair follicles get plugged in acne vulgaris
increase in sebum production in como w increased production and impaired shedding of corneocytes linint the upper portion of hair follicle–lead to comedo formation
comedones are characteristic lesions in what kind of acne
non inflammatory acne
comedones can be
closed (white heads) or open (blackheads)
how does inflammatory acne differ from non inflam?
inflam also has comedones, but the inflammatory lesions vary depending on type of inflam response
how is inflam acne diff from non inflam acne appearance wise
inflam acne is larger and discolored
can have pustules, cysts, nodules
how do retinoids work for acne vulgaris
topical agent
normalize follicular keratinization
expulsion of existing keratinaceous plugs
prevention of formation of new lesions
how does benzoyl peroxide work for acne vulgaris
topical agent-it has antibacterial effects and also anti-inflam properties
are tetracyclines antiinflam?
yes, they decrease proinflammatory mediators
side effect of doxycycline
pill esophagitis, photosensitivity
MOA of oral contraceptives
systemic agent for treating acne vulgaris
blocks production of androgens
indications for isotretinoin
severe nodulocystic acne
scarring
recalcitrant to systemic antibiotics or topicals
good thing is: many pts who complete a course of this don’t get acne again
acne rosacea
pathogenesis is multifactorial-related to hyperreactivity
easy blushing
lacks comedones
