chapter 6

Question 1

epidermis

Answer 1

derived from ectoderm, embryo layers

Question 2

basement membrane

Answer 2

between epidermis and dermis

Question 3

first cell layer (stratum basale)

Answer 3

deepest cell layer where active mitosis produces new cells for the epidermis

Question 4

second layer (periderm)

Answer 4

one cell layer thick in embryo, but become multiple layers in adult

Question 5

dermis

Answer 5

derived from dermatome
-one of three cell populations in the somite of the embryo

Question 6

underlying connective tissues (hypodermis, superficial fascia)

Answer 6

below the dermis and holds the integument down the superficial muscle
-may be a lot of adipose tissue here too

Question 7

during growth, invasion of dermis occurs

Answer 7

neural crest cells produce chromatophores (pigment cells)
-blood vessels and nerves

Question 8

epidermis keratinized

Answer 8

this is done for protection

Question 9

keratinocytes

Answer 9

cells accumulating keratin
-keratin is second most important adaptation allowing amniotes to become fully terrestrial

Question 10

stratum basale

Answer 10

mitosis

Question 11

stratum corneum

Answer 11

outer layer of dead keratinocytes

Question 12

callus

Answer 12

skin with thick stratum corneum

Question 13

hair

Answer 13

keratin structures projecting from follicles in dermis
-cells lining dermal papillae secrete keratin that produces the hair (matrix cells)

Question 14

matrix cells

Answer 14

within hair papillae produce keratin
-continually produce keratinocytes

Question 15

arrector pili

Answer 15

muscles that erect hair in response to cold or fear

Question 16

vibrissae

Answer 16

whiskers, used for nocturnal motion detection

Question 17

quills

Answer 17

thickened hairs for defense

Question 18

sebaceous glands

Answer 18

produce oily secretion (sebum) to protect hair

Question 19

sebum

Answer 19

oily secretion used to protect hair

Question 20

sweat glands

Answer 20

produce watery secretion (sweat) to cool body

Question 21

sweat

Answer 21

watery secretion to cool body

Question 22

scent glands

Answer 22

modified sweat and function as social communication… mark territory, identify individuals or for courtship

Question 23

mammary glands

Answer 23

modified sebaceous glands, functional only in females, produce milk for young

Question 24

keratin specializations

Answer 24

nail, claw, hooves

Question 25

horns

Answer 25

bony projection from skull plus overlying integument-derived keratin sheath
-what you see is keratin, not bone
-horns in both males and females but larger in males
-usually unbranched and grow throughout the life of the individual

Question 26

keratin sheath

Answer 26

keratin outer layer

Question 27

antlers

Answer 27

bone covered by skin when growing
-what you see is just bone
-branched
-only males have them
antlers fall off each year and have to be regrown

Question 28

velvet

Answer 28

covers antlers and falls off when antler is fully developed

Question 29

baleen

Answer 29

whales don’t have teeth but have hairlike structures made of keratin that are used for filtering out small crustaceans from the water

Question 30

giraffe

Answer 30

horns are stunted antlers in velvet throughout life
-both males and females have them

Question 31

rhinoceroses

Answer 31

hair horns
-made of keratinized epidermal fibers
-no bony core

Question 32

caribou

Answer 32

antlers in both sexes
-antlers shed annually

Question 33

pronghorn antelope

Answer 33

branched horns
-outer keratinized sheath is branched but not the inner bony core
-both sexes have them
-outer keratinized sheath is shed annually, but not the inner bony core

Question 34

placoid scales

Answer 34

Chondrichthyes
-enamel exterior and dentin interior
-internal pulp cavity
-forerunner of the tooth

Question 35

collagen plies

Answer 35

dermal collagen forms distinct layers that permit flexure without wrinkles
-45 degree angles

Question 36

Osteichthyes mucus

Answer 36

unicellular glands in epidermis produces this

Question 37

plates (scales)

Answer 37

dermis produces this

Question 38

cosmoid scales

Answer 38

bone + dentin + enamel

Question 39

ganoid scales

Answer 39

bone + enamel

Question 40

teleost scales

Answer 40

only bone

Question 41

thin epidermis (thin stratum corneum)

Answer 41

permits cutaneous respiration
-oxygen to diffuse through water, through skin into capillaries below skin
-important respiratory organ

Question 42

mucus (and poison) glands

Answer 42

present in amphibians

Question 43

reptile scutes

Answer 43

boneless epidermal scales are thick patches of keratin

Question 44

molt

Answer 44

entire epidermis may be lost during this