Epidermis Flashcards
What accessory cells are found in the epidermis?
Langerhan cells, melanocytes, and sweat ducts
Where does desmoglein 1 localize?
entire dermis, but mainly the upper epidermis
Where does desmoglein 3 localize?
Basal layer
Where are the keratohyaline and the lamellar granules located?
Granule layer of the epidermis
Where is profilaggrin located?
the keratohyaline granules
What is the function of filaggrin
promotes aggregation and stabilization of intermediate filaments
What is the function of Lamellar granules (Odland bodies)?
they release lipids and sterols into the intercellular space at the upper levels of the granular layer
During embryogenesis, keratinocytes migrate from _____?
dorsal neural crest cells
What are natural moisturizing factors?
free AAs, lactic acid, urea, and salts in the corneocytes
Disruption of desquamation may result in _____
xerosis
What is the transit time from the basal layer to the granular layer?
12-14 days
What is the desquamation rate for cells in the cornified layer?
12-14 days
What is Acanthosis?
increased cell proliferation in the stratum spinosum
What is hyperkeratosis?
thickening of the stratum corneum due to increased production of corneocytes or reduced desquamation of corneocytes
What is Lichenification?
Thickening of the stratum spinosum and stratum corneum in response to repeated scratching or rubbing–> leads to leathery and hyperpigmented skin
Psoriasis is an example of what kind of hyperplasia?
Acanthosis
Keratosis pilaris is an example of what kind of hyperplasia?
Hyperkeratosis
Lichen simplex chronicus is an example of what kind of hyperplasia?
Lichenificiation
What are examples of diseases of cornification?
Ichthyosis vulgaris (IV) and Palmaoplantar Keratoderma (PPK)
What is keratosis pilaris?
a follicular retention hyperkeratosis overlying hair folicles of the extensor upper and lower extremities and buttocks
What other pathologies is Ichthyosis vulgaris associated with?
atopy and keratosis pilaris
Describe common features of Ichthyosis vulgaris.
retention hyperkeratosis autosomal dominant dry skin with white adherent scaling improves with age exacerbated by cold and decreased humidity
Describe common features of Palmoplantar Keratoderma
hyperkeratosis of the palms and soles
autosomal dominant and recessive
keratin mutation resulting in abnormal pairing of type I and II keratins
Describe the 3 variants of Palmoplantar Keratoderma
Diffuse: thick, yellow plaques of the entire palm and/or sole (maybe hyperhidrosis)
Focal: hyperkeratosis over localized pressure points
Punctate: hyperkeratotic papules and nodules (often misdiagnosed as warts)
