Integumentary System

Question 1

What are the functions of skin? (7)

Answer 1

protection from injury, infection, over-hydration, parasites, predators; thermoregulation; sensation; gland secretion (mammary gland); patterning; movement; economic

Question 2

What does the hypodermis/subcutis develop from?

Answer 2

Mesoderm

Question 3

What does trunk/limb dermis develop from?

Answer 3

mesoderm-> somites-> dermatome

Question 4

What do melanocytes and facial dermis develop from?

Answer 4

neural crest

Question 5

what does the epidermis develop from?

Answer 5

ectoderm

Question 6

what is hypodermis made of?

Answer 6

loose connective tissue and fat

Question 7

what clinical things is hypodermis the site of? (3)

Answer 7

emphysema (gas build-up), oedema (fluid build-up), subcutaneous injection

Question 8

Describe adipocytes

Answer 8

Cells most able to change size (at least x10), have large lipid droplet vacuole surrounded by thin layer of very metabolically active cytoplasm

Question 9

what is the function of white adipose tissue?

Answer 9

storage

Question 10

what is the function of brown adipose tissue?

Answer 10

thermogenesis

Question 11

what does brown adipose tissue have a lot of?

Answer 11

mitochondria

Question 12

describe the dermis

Answer 12

tough interwoven matrix of collagen and elastin with blood and nerve supply, important in injury as causes gaping of wounds due to elasticity

Question 13

what is the dermis called in the hoof and horn?

Answer 13

corium

Question 14

what is the epidermis made of?

Answer 14

4 layers of stratified squamous cells: stratum basale, stratum spinosum, stratum granulosum, stratum corneum

Question 15

describe stratum basale

Answer 15

folded and germinal

Question 16

describe stratum spinosum

Answer 16

shrunken, retain desmosomes between cells

Question 17

describe stratum granulosum

Answer 17

has keratinisation

Question 18

describe stratum corneum

Answer 18

has shrunken nuclei and lots of keratin, surface layer of skin, shed into environment as squames

Question 19

how thick is epidermis on flank?

Answer 19

20 um

Question 20

how thick is epidermis on nose?

Answer 20

600 um

Question 21

how thick is epidermis on pads?

Answer 21

1800 um

Question 22

does epidermis have direct blood supply?

Answer 22

no

Question 23

is epidermis innervated?

Answer 23

only by very tips of sensory nerves

Question 24

what are melanins?

Answer 24

polymers of indoles with side chains

Question 25

what are the two types of melanin?

Answer 25

eumelanin (black/brown) and phaeomelanin (red/yellow)

Question 26

what does the pad of a dog paw have?

Answer 26

conical papillae

Question 27

what are melanocytes derived from?

Answer 27

neural crest

Question 28

what are melanocytes stimulated by?

Answer 28

melanocyte stimulating hormones α,β,γ

Question 29

how does UV light lead to increased melanogenesis?

Answer 29

causes DNA damage leading to pyrimidine fragments

Question 30

what muscle in the ectoderm contracts the hair follicle?

Answer 30

arrector pili muscle

Question 31

what is the technical term for whiskers?

Answer 31

vibrissae

Question 32

what are the types of sebaceous gland? (3)

Answer 32

simple, specialised, scent

Question 33

what is the function of simple sebaceous glands?

Answer 33

secrete sebum/lanolin which keeps skin pliable, waterproof and water repellent

Question 34

what glands secrete ear wax?

Answer 34

ceruminous (specialised sebaceous)

Question 35

what scent glands do ruminants have? (4)

Answer 35

caudal horn, preorbital, interdigital, inguinal

Question 36

what scent glands do pigs have?

Answer 36

preputial and carpal

Question 37

what scent glands do rabbits have?

Answer 37

inguinal and chin

Question 38

what scent glands do carnivores have? (5)

Answer 38

dorsal tail (dog), circumoral (cat), circumanal, paranal, anal

Question 39

what are the paranal sacs called?

Answer 39

anal glands

Question 40

what are the types of sweat glands?

Answer 40

apocrine, mammary, eccrine, venom