Vertebrates 5c - Integument of the rest Flashcards
Amphibian skin
Glandular (granular, mucous), no scales, thin protective layer (stratum corneum)
Granular gland in amphibian
Some make antimicrobials, toxins (like parotid),
Mucous in amphibians
Help keep skin moist, traps bacteria and parasites
Reptilian skin
Thick stratum corneum; epidermal keratin plates/scales; only from epidermis; no mucous glands
Layers of reptilian epidermis
Outer epidermal generation, fission zone, inner epidermal generation, stratum germinativum (stem cells), then dermis.
Problem with reptilian skin?
Very thick and dead, can’t expand. Must shed of molt. Fission zone becomes active and it molts. The living cells below keratinize and die before molting.
Reptilian claws
Made of keratin. Used for grasping, digging. Hunting (raptors)
Bird skin
Scales of keratin on feet, claws/talons. Similar to reptiles.
Feathers
An outgrowth, interaction of epidermis and dermis to leave dead cells with lots of keratin. Similar to hair formation.
Vane and Rachis
The fan or surface area and The central shaft
Barbs and barbules
Barbs perpendicular the rachis, barbules perpendicular to barbs
Hooklets
On the barbules. Hold the vane together, Can separate and reattach (preening)
Contour feathers
Most of the feathers on the outside of the bird. Different types.
Flight feathers
Some of the longest feathers; rachis is to one side of the feather (asymmetrical). Primary on outer wing, secondary inner. Coverts on the front edge of wings
Down feathers
Not as organized, no hooklets. Underneath contour feathers, insulate
Bristle feathers
Found in some birds around the eyes to protect them. Longer rachis (relatively)
Main roles of feathers
Flight/locomotion, and insulation.
Muscles and feathers
All contour feathers have arrector pili attached. Used to fluff up and insulate, and to rotate to help in flight.
Evolution of feathers
Proto-feathers about 200mya. Shape with just rachis, barbs but not barbules, etc. True feathers and Flight came around 150mya
Dinos
Some may have had many true feathers. (like Yutyrannus huali).
What needed for flight?
Feathers, light, need wings
Archaeopteryx
First wing/bird. Has feathers and wings, but still had teeth. Might not have flown very well (shorter wings)
Microraptor
Has longer wings but…….
Beak
Forms over the bone in lower and upper jaw. Made of keratin. Makes head lighter, replaced teeth. The beak has evolved for certain feeding methods/diets
Flamingo beak
Beak strains algae and invert. Filter feeding.
Uropygial gland
aka preening gland, common in ducks, geese. Secretes waxy substance. Bird preens to spread this.
Mammals
Stratum corneum thickness varies b/w animals and areas of same animal.
Hair
Mammalian synapomorphy. Follicle is alive, but hair itself is dead cells. Keratin. Formed from interaction b/w dermis and epidermis.
Pelage
Guard hairs and underhair. Most animals have this
Quills
Same formation as hair. Hollow core, with hooks on end
Vibrissae
Whiskers. Gives positional info, help it determine if animal can fit through an opening etc. Sensitive, nerve endings. Any movement, even air, stimulates them.
Unguis
Claws, hoofs, nails. Keratinized, similar to claw.
Ungulates
Animals with hoofs. Surrounds the bone. Wall (vertical) is unguis, sole of foot is unguis.
Nails
Role is to protect the sensitive ends of the fingers. Doesn’t get in the way like a claw so you can grip.
Horns
Horny layer, epidermal layer, and bony core. Usually in both sexes, sometimes sexual dimorphism. Large ones have lots of air pockets for weight.
Rhino horn
It is only keratin.
Difference b/w horns and antlers
Antlers are not present all the time…
Antler
In the Cervidae family. Usually just males, or smaller in females. Covered in skin with small hairs (velvet), highly vascularized so bony part of antler can grow quickly.
Antlers growth and falling off
Grows from protuberances on skull. Cells on protuberance die so they fall off. Usually grow bigger the next year.
Ossicones
Horns covered in skin, less keratinized. Horns in giraffes.
Baleen
Long keratinized fibers that form a plate/strainer. Loose skin on throat allows them to get a lot of water in mouth, then force water out, and scoop food off with tongue.
Sebaceous glands
Produce oil/wax which can help waterproof fur. Usually associated with hair follicle
Sweat glands
Eccrine: onto skin, not hair; salts and water, used for cooling. Apocrine: more convoluted, onto hair; salts, water, scents and pheromones
Mammary glands
Mammalian synapomorphy. Convoluted, may have evolve from apocrine glands. Produce milk glands. Controlled by oxytocin and prolactin. Ducts/alveolus open into gland cistern then teat.
Mammary glands in monotremes?
Secrete milk onto the skin, no teats.
Vasodilation and constriction
Allows for cooling or retaining heat. Fur usually prevents evaporative cooling, so ears (less hair) help cool.
Blubber
Large deposits of subcutaneous fat. Important in insulation, also some role in buoyancy for aquatic animals.
