Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
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
|
lymphocytes
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
|
medulla
|
|
|
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?
|
cuticle
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?
|
merocrine
|
|
|
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 |
