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What are the epidermal derivatives?
- 1. Beaks
- 2. Epidermal scales
- 3. feathers
- 4. Hair
- 5. Claws, nails, hooves
- 6. Horns
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What are beaks?
Beaks are tickened epidermis covering the jaws.
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What are epidermal scales?
Embryological outpushing of epidermis containing a small papilla of mesodermal tissue, connected by narrow zones of uncornified epidermis.
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What do feathers derive?
they derive from the stratum corneum.
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Feathers do not cover the body, but lie in tracts called _____; featherless areas are _____.
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What are the different types of feathers?
- 1. Down (Plumules)
- 2. Filoplumes
- 3. Contour feathers ( flight feathers)
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Contour feathers (Flight feathers) are divided into two catagories called_______ and _______.
- 1. Remiges (Wings)
- 2. Retrices (Tail)
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What are the components of contour feathers?
- 1. Quill
- 2. Shaft (Rachis)
- 3. Aftershaft
- 4. Barb
- 5. Barbule
- 6. Follicle
- 7. Vane
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What is the function of the quill?
Inserts into the skin.
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What is the function of the shaft (Rachis)?
Main support beam for feather.
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What is the function of the aftershaft?
a small secondary feather located near the plume base of some feathers.
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What are the function of barbs?
they are small lines that extend from the shaft to make the cane of the feather.
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What is the function of the barbule?
smaller hook-like offshoot from the barb that holds barbs together.
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What is the function of the follicle?
the area in the skin from which the feather grows.
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What is the function of the vane?
the collection of barbs that provide a wind resistant surface for flight.
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______ is strictly mammalian, purley epidermal in origin.
Hair
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What is lanugo?
A downy coat of hair on a fetus, lost just before or just after birth.
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What are the parts of the hair?
- 1. Shaft
- 2. Root
- 3. Hair follicle
- 4. Bulb
- 5. Dermal papilla
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Where is the shaft of hair located?
above the skin
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Where is the root of hair located?
within skin.
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Where is the hair follicle located?
pit sunk in dermis.
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Where is the bulb located?
is is a hollow structure surrounding dermal papilla.
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What is the dermal papilla?
it contains connective tissue, blood vessels.
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What are the structures indicated by the cross section of a hair?
- 1. Cuticle
- 2. Cortex
- 3. Medulla
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What is the cuticle?
outside, it is a pattern of scales.
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What is the cortex?
it is a layer inside the cuticle.
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What is the medulla?
it is the inner layer, pigment is usually found there.
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What are claws, nails, and hoves?
They are highly keratinized structures at tips of digits in amniotes.
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The _____ is the harder upper portion of a nail of claw.
Unguis
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_______ is the softer under portion of nail of claw.
Subunguis
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What animal contains a true horn and what are the characteristics?
- Cattle
- These never shed, made of a bony core and dpidermal sheath.
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What animal contains a pronghorn and what are the characteristics?
- Pronghorn
- a true horn whose bony core is never shead, but the epidermal sheath is shed.
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What are the characteristics of giraffe horn?
bony core is covered by living skin.
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What animals contain antlers and what are the characteristics?
- Deer
- bony core grows anew each year, velvet is the skin.
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What animal contains a rhinohorn and what are the characteristics?
- Rhino
- agglutinated hair-like filaments, always grow, never shed.
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