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50 Cards in this Set
- Front
- Back
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Describe epidermis.
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- a continuous layer of epithelial cells
- no blood vessels - depends of underlying dermis for nutrition |
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What are the four layers of the epidermis?
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stratum corneum
stratum lucidum stratum granulosum stratum germinativum |
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What is keratinization?
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process seen in amniotes; includes flattening, loss of nuclei, thickening of the cell membrane
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What is desquamation?
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cells die and are sloughed off at times
exfoliation |
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Describe the dermis?
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contains small vessels, nerve endings, sweat and sebaceous glands, pigment cells
composed of collagen and elastin fibers in a gel-like matrix |
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What are the layers of the dermis?
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papillary layer
fibrous reticular region (cornium) subcutaneous layer |
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What layer is leather made from?
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cornium (fibrous reticular layer)
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What is the panniculus adiposus?
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fatty tissue (in dermis)
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What is the panniculus carnosus?
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muscle tissue (cutaneous muscle)
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What are beaks?
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thickened epidermis covering the jaws
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What are epidermal scales?
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embryological outpushing of epidermis containing small papilla of mesodermal tissue, connected by narrow zones of uncornified epidermis
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What are feathers?
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a derivative of the stratum corneum
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What are pterylae?
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the tracts that the feather lie in
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What is the apteria?
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featherless areas
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What are the types of feathers?
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- down (plumules)
- filoplumes - contour feathers |
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What are the types of contour feathers?
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- remiges (wings)
- retrices (tail) |
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What is a quill?
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inserts into the skin
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What is the shaft (rachis)?
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main support beam for feathers
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What is the aftershaft?
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a small secondary feather located near the plume base of some feathers
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What is the barbule?
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smaller hook-like offshoots from the barb that holds barbs together
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What is the barb?
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the small lines that extend from the shaft to make the vane of the feather
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What is the follicle?
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the area in the skin from which the feather grows
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What is the vane?
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the collection of barbs that provide a wind resistant surface for flight
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Describe hair.
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strictly mammalian, purely epidermal in origin
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What is languo?
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downy coat of hair on a fetus, lost just before or just after birth
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What is the shaft (hair)?
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hair above the skin
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What is the root (hair)?
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hair within the skin
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What is the hair follicle?
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pit sunk into dermis
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What is the bulb (hair)?
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hollow structure surrounding dermal papilla
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What is the dermal papilla?
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contains connective tissue, blood vessels
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What is the cuticle?
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outside; is a pattern of scales
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What is the cortex (hair)?
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layer inside the cuticle
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What is the medulla (hair)?
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inner layer, pigment is usually found there
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Describe claws, nails, hooves.
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highly keratinized structures at tips of digits in amniotes
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What is the unguis?
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the harder upper portion of a nail or claw
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What is the subunguis?
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the softer under portion of a nail or claw
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What is true horn (cattle)?
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never shed, made of bony core and an epidermal sheath
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What is a pronghorn?
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a true horn whose bony core is never shed, but the epidermal sheath is shed
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What is a giraffe horn?
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bony core is covered by living skin
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What is an antler?
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bony core grows anew each year, velvet is the skin that covers the antlers
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What is a rhinohorn?
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agglutinated hair-like filaments, always grows, never shed
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What type of glands do fish have?
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mucous and poison
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What types of glands to amphibians have?
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granular and mucous
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What type of glands do birds have?
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preen
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What types of glands do mammals have?
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sebaceous, sweat, and mammary
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What are sebaceous glands?
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oil glands
i.e. lanolin |
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What is baleen?
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whales that filter plankton
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What are the types of dermal scales?
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- cosmiod scales
- ganoid scales - cycloid and ctenoid scales - placoid scales |
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what are cosmoid scales?
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primitive bony scales made of several layers
top layer: enamel second layer: cosmine layer third layer: spongy bone fourth layer: lamellar bone |
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What are granoid scales?
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most primitive of extant forms; several shiny, hard layers of ganonine are present
found in gars |
