Reptile and Amphibian Dermatology Flashcards
reptiles
turtles, tortoises, lizards, snakes, crocodiles, alligators, etc
- adapted to land
- shelled eggs
- thick, keratinized skin
functions in skin in reptiles
- protection
- thermoregulation
- sensory
- defense
- display
amphibians
frogs, toads, caecilians, salamanders, newts
- adapted to water
- gelatinous eggs
- thin, non-keratinized skin
function of skin in amphibians
- protection
- thermoregulation
- sensory
- defense
- display
- fluid/ion balance
- respiration
epidermis in amphibians
- superficial mucus layer
- thin epidermis
- minimally/non-keratinized
- stratified squamous epithelium
- no scales
epidermis in reptiles
- thick epidermis
- heavily keratinized
- scaled
alpha vs beta keratins
alpha: soft/flexible
beta: firm/hard
overlapping scales
outer beta-keratin regions overlap each other
connected by inner alpha-keratin regions
tubercular scales
alternating regions of beta and alpha keratins
reduced overlapping scales
small regions of overlapping beta and alpha keratins
glands in amphibians
abundant glands
- mucus
- granular (posions)
glands in reptiles
aglandular
exceptions:
- heat sensing pits
- parietal eye
- femoral pores
- cloacal scent glands
dermis in amphibians
rare ossifications
exceptions: caecilians
- bands of mineralization for digging
dermis in reptiles
ossifications common
osteoderms - formed from scleroblasts in deep dermis
- lizards, croc, tortoises
chromatophores
layered dermal cells that express colors (either pigment or crystals that reflect color)
color is only visible when cell is stretched
melanophores, xanthophores, iridophores
controlled by neurohormonal stimulation
do reptiles/amphibians have melanocytes in the epidermis
NO
only chromatophores in the dermis
ecydysis
normal shedding process
resting vs renewal phase
resting phase
normal skin
single skin layer on top of stratum germinativum
- old stratum corneum
- old intermediate zone
- stratum germinativum
renewal phase
proliferation of new skin via hypertrophy of the stratum germ. and sloughing of old skin
- old stratum corneum
- old intermediate zone
- cleavage zone
- new stratum corneum
- new intermediate zone
- stratum germinativum
cleavage zone
area of lymphatic fluid that forms between the old and new skin layers prior to the old skin sloughing off
cornification of the new skin layers must occur BEFORE fluid appears
horizontal desquamation
little bits of skin exfoliate at a time
- crocodilians, chelonians
vertical desquamation
entire body or pieces of body exfoliate at a time
- snakes, geckos, frogs, lizards
