Reptile and Amphibian Dermatology

Question 1

reptiles

Answer 1

turtles, tortoises, lizards, snakes, crocodiles, alligators, etc

• adapted to land
• shelled eggs
• thick, keratinized skin

Question 2

functions in skin in reptiles

Answer 2

• protection
• thermoregulation
• sensory
• defense
• display

Question 3

amphibians

Answer 3

frogs, toads, caecilians, salamanders, newts

• adapted to water
• gelatinous eggs
• thin, non-keratinized skin

Question 4

function of skin in amphibians

Answer 4

• protection
• thermoregulation
• sensory
• defense
• display
• fluid/ion balance
• respiration

Question 5

epidermis in amphibians

Answer 5

• superficial mucus layer
• thin epidermis
• minimally/non-keratinized
• stratified squamous epithelium
• no scales

Question 6

epidermis in reptiles

Answer 6

• thick epidermis
• heavily keratinized
• scaled

Question 7

alpha vs beta keratins

Answer 7

alpha: soft/flexible
beta: firm/hard

Question 8

overlapping scales

Answer 8

outer beta-keratin regions overlap each other

connected by inner alpha-keratin regions

Question 9

tubercular scales

Answer 9

alternating regions of beta and alpha keratins

Question 10

reduced overlapping scales

Answer 10

small regions of overlapping beta and alpha keratins

Question 11

glands in amphibians

Answer 11

abundant glands
- mucus
- granular (posions)

Question 12

glands in reptiles

Answer 12

aglandular

exceptions:
- heat sensing pits
- parietal eye
- femoral pores
- cloacal scent glands

Question 13

dermis in amphibians

Answer 13

rare ossifications

exceptions: caecilians
- bands of mineralization for digging

Question 14

dermis in reptiles

Answer 14

ossifications common

osteoderms - formed from scleroblasts in deep dermis
- lizards, croc, tortoises

Question 15

chromatophores

Answer 15

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

Question 16

do reptiles/amphibians have melanocytes in the epidermis

Answer 16

NO

only chromatophores in the dermis

Question 17

ecydysis

Answer 17

normal shedding process

resting vs renewal phase

Question 18

resting phase

Answer 18

normal skin

single skin layer on top of stratum germinativum

• old stratum corneum
• old intermediate zone
• stratum germinativum

Question 19

renewal phase

Answer 19

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

Question 20

cleavage zone

Answer 20

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

Question 21

horizontal desquamation

Answer 21

little bits of skin exfoliate at a time
- crocodilians, chelonians

Question 22

vertical desquamation

Answer 22

entire body or pieces of body exfoliate at a time
- snakes, geckos, frogs, lizards