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66 Cards in this Set

  • Front
  • Back
what are the layers of the epidermis
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
what is the difference b/w thick skin and thin skin
thick skin: all 5 layers, hairless (glabrous), only on palms of hands and soles of feet.

thin skin: no stratum lucidum by LM, most parts have hair (vellous)
what are the two layers of the dermis?
papillary layer: just beneath epithelium in dermal papillae; LOOSE CT

reticular layer: deep to papillary layer; DENSE IRREGULAR CT
how does keratinization occur?
tonofibrils formed in stratum basale and stratum spinosum.

keratohyalin granules produced in stratum granulosum (basophilic)

keratohyalin granules and tonofibrils associate in stratum lucidum
what are lamellar bodies?
membrane-coating granules.

they seal spaces between keratinocytes. they are membrane bound organelles first produced in stratum spinosum, they fuse w/ plasma mbn in stratum granulosum and secrete lipid-like stuff into intercellular space
where are melanocytes derived from?
derived from neural crest cells
where are melanocytes located?
stratum basale
what do mealoncytes look like on H&E?
paler staining that keratinocytes because keratinocytes have taken up the melanosomes through phagocytation
what are melanosomes?
mbn bound organelles derived from golgi; where melanin synth occurs
how is the distribution/amount of melanocytes different among different races?
same # of melanocytes

different #s of melanosomes, different size of melanosomes, and different amount of melanin per melanosome
what is a Langerhans cell?
antigen-presenting cell that presents to T cells in the stratum spinosum of epith

pale staining
what is a langerhans cell derived from?
derived from bone marrow
what is a birbeck granule?
mbn bound cytoplasmic organelle in a langerhans cell. looks like a tennis racket on EM.

part of recycling endosome system.
where are langerhans cells found?
in the stratum spinosum of the epithelia
what is a merkel cell?
fxn as touch receptors, common in fingertips

rare cells found in stratum basale of thick skin

base of cell in contact w/ afferent nerve terminal, or Merkel disc
what do merkel cells look like?
by EM, small, electron dense granules near basal end of cell

by LM, pale staining
what are the two layers of the dermis?
papillary layer
reticular layer
what is the papillary layer made of?
loose conn. tissue
what is the reticular layer made of?
dense irregular CT
what are dermal papillae?
projections of dermis that interdigitate w/ projections from epidermal ridges
what is the dermis connected to the epithelium by?
connected by basement mbn (basal lamina + lamina reticularis) and hemidesomosomes
what is a meissner's corpuscle?
low frequency touch receptor

in papillary layer of hairless skin

looks like a big mitochondrion
what is a pacinian corpuscle
receptor for pressure/vibrations

in deeper dermis/hypodermis

looks like an onion
what are the major cells for immune response in the dermis

plasma cells also help out
what are the major cells for inflammatory response in the dermis?
neutrophils (acute)

macrophages (chronic)
what is the function of the dermis?
regulates body temp by:

1. arteriovenous anastomoses in reticular layer
2. control of blood flow to capillary beds of papillary layer
what is the hypodermis?
loose CT + adipose tissue

not part of skin; below the dermis

aka superficial fascia/panniculus adiposus
what are the two types of hairs in adults?
vellus hairs - thin, short, poorly pigmented

terminal hairs - thicker, longer, more heavily pigmented
what are the stages of the hair life cycle?
anagen - period of active growth

catagen - invollution where lower part of follicle atrophies

telogen - resting period b/w end of follicular atrophy and shedding
what does the hair bulb give rise to?
medulla, cortex, and cuticle

and inner root sheath
what are the parts of the hair, from inner to outer?
medulla, cortex, cuticle, inner root sheath, outer root sheath, and glassy membrane

the dermal papilla is at the base
what part of the hair is moderately keratinized
what part of the hair is heavily keratinized?
cortex and cuticle
what is the outer root sheath derived from?
it's continuous with the surface epithelium; it is not produced from the hair bulb
what other structures are associated with the hair follicle?
sebaceous gland and arrector pili muscle

sometimes apocrine sweat gland
what does hair color depend on?
ratio of eumelanin to pheomelanin (red)
what is the nail plate?
hard portion of nail; hard keratin; = stratum corneum
what is the nail root?
proximal part of nail plate

stem cells become keratinized here
what is the nail matrix?
where the stem cells proliferate
what is a lunula?
partially keratinized cells at the proximal end of the nail plate
what is the nail bed?
stratum basale and stratum spinosum; underneath the nail plate
what is the eponychium?

hard keratin
what is the hyponychium?
thick epithelial layer that secures the free end of the nail plate
what kind of secretion method does a sebaceous gland use?
holocrine secretion
classify sebaceous glands.
simple branched acinar exocrine glands
where are sebaceous glands found?
in thin skin
where are the stem cells of each acinus of a sebaceous gland?
resting on the basal lamina
what is sebum made of? what are its function?
debris from ruptured cells,lipids

coats hair, lubricates skin, antibacterial/antifungal effects
classify eccrine sweat glands
simple coiled tubular exocrine glands.
where do the ducts of eccrine sweat glands open?
ducts open directly onto the skin surface. they are NOT associated with hair follicles.
where are eccrine sweat glands found?
all over body, except lips and external genitalia
what method of secretion do eccrine sweat glands use?
how do you tell the difference b/w the secretory portion and the ducts of eccrine sweat glands?
secretory portion: columnar/cuboidal/pyramidal epithelia
wider than duct
lighter than duct
surrounded by myoepithelial cells

duct: stratified cuboidal
what are the two types of cells in the secretory portions of eccrine sweat glands?
light cells - pump ions

dark cells - secrete glycoproteins

only seen on EM
what do eccrine sweat glands do?
regulate body temp, also secretory organs (urea, ammonia,etc)
classify apocrine sweat glands
coiled tubular exocrine glands

ducts may or may not branch
where are apocrine sweat glands found?
axilla, areola, nipple, perianal region, and external genitalia
how do you tell the difference b/w the secretory portion and the duct of apocrine sweat glands?
secretory portion:
WIDE lumen, which may have secretory material
lined by simple epithelium of 1 cell type
apical end has bleb-like protrusions
surrounded by myoepithelial cells

Duct: narrow, 2-3 layers of cuboidal cells
what method of secretion do apocrine sweat glands use?
glycoproteins - merocrine
ammonia, lipids

cyptoplasmic fragments - may or may not be apocrine
what stimuli is needed for apocrine glands?
emotional stimuli, not heat
what are ceruminous glands (ear canal), gland of Moll (eyelid), and mammary glands?
modified apocrine sweat glands
what is psoriasis?
disease w/ increase in cell proliferation, causing an accumulation of cells in the stratum corneum

pink/red areas w/ flakes/plaques
what is basal cell carcinoma?
cancer of stratum basale

most common skin cancer

by UV radiation; least deadly
what is squamous cell carcinoma?
cancer in stratum spinosum; probably by radiation or chemical agents
what are malignant melanomas?
cancer of melanocytes

rapidly dividing, invasive, most deadly skin cancer
what are warts?
benign epidermal growths

by papilloma viral infection of keratinocytes

common in young children, young adults, and immunosuppressed