Skin Flashcards
interesting facts about the skin
largest single organ; ~16% of body weight; ~15-20 sq ft SA; however doesn’t get the most cardiac output
Going from most superficial to deep, what are the layers of the epidermis?
Corneum, lucidum, granulosum, spinosum, basale.
In which layer of the epidermis do cells divide and begin to form the more superficial layer?
stratum basale
what cells make up the stratum basale and what is their function?
melanocytes and keratinocyes; melanocytes synthesize melanin and transfer it to keratinocytes which divide and migrate (28 days)
In which layer of the epidermis do the cells die?
stratum lucidum
Tinea corporis (epidermophyton floccosum)
(ringworm); superficial skin infection that only effects the epidermis; common and thrives in moist environments; as it multiplies, it has a raised active border with central clearing.
What is the treatment for ringworm?
treat for 4 weeks w/ ketoconazole cream 2% - apply twice a day, continue 1 week after lesion disappears. (due to 28 day cell cycle)
What structure is responsible for the appearance of finger prints?
dermal papilla
What are the two factors that determine a person’s unique fingerprint?
part genetically determined and partially determined in utero.
basal cell carcinoma
benign, slow growing, invasive.
tumor of cells along the basal layer of keratinocyte (no longer take on characteristics of normal keratinocyte) they start growing and becoming ulcurative. If not treated, will grow locally, no malignant potential.
squamous cell carinoma
malignant potential; within the stratum granulosum; if not treated can metastisize. Produces ulcerative lesion - shadow ulcer not super painful.
melanoma
mutated melanocytes; superficial to bm; if identified before penetrating the bm then curable; if not, become malignant, metastatic and deadly.
What is the procedure used to remove melanoma?
Mohs surgery; wide and deep circular incision until borders are clear
Seborrheic keratosis
waxy appearing lesion that is raised; rough/warty looking; treated by freezing off or cut out by blade. common. not premalignant
actinic keratosis
is premalignant; common; found in sun exposed areas like neck arms face
lentigos
liver spots; hyperpigmentation; flat/macular
What is the predominant cell type in the dermis and what is its function?
fibroblasts; secretes collagen and elastic fibers
What is the primary fxn of collagen and elastin in the dermis and what happens with aging?
collagen = strength elastic = recoil
aging: collagen crosslinks and decreases and recoil decreases (wrinkles and tenting)
Subcutaneous layer
aka hypodermis/superficial fascia; binds skin loosely to deep fascia = ability to slid on itself; contains fat, sweat glands, nerves, vessels
psoriasis
common skin disease; an acceleration of the 28 day keratinocyte cycle (make it to surface in 5-7 days); they build up b/c don’t slough off fast enough so end up with plaques
scleroderma
rare; involves abnormal collagen synthesis and degradation; collagen becomes hardened (in the skin and pleura)
What is the outermost covering of the muscle?
deep fascia; is thin but very tough
decubiti
pressure ulcers/bedsores
what are the different stages of decubiti?
1: skin is unbroken but inflamed
2: skin is broken to epidermis or dermis
3: extends to subQ fat
4: extends to muscle or bone
