Integumentary System Flashcards
What are the functions of skin? (7)
protection from injury, infection, over-hydration, parasites, predators; thermoregulation; sensation; gland secretion (mammary gland); patterning; movement; economic
What does the hypodermis/subcutis develop from?
Mesoderm
What does trunk/limb dermis develop from?
mesoderm-> somites-> dermatome
What do melanocytes and facial dermis develop from?
neural crest
what does the epidermis develop from?
ectoderm
what is hypodermis made of?
loose connective tissue and fat
what clinical things is hypodermis the site of? (3)
emphysema (gas build-up), oedema (fluid build-up), subcutaneous injection
Describe adipocytes
Cells most able to change size (at least x10), have large lipid droplet vacuole surrounded by thin layer of very metabolically active cytoplasm
what is the function of white adipose tissue?
storage
what is the function of brown adipose tissue?
thermogenesis
what does brown adipose tissue have a lot of?
mitochondria
describe the dermis
tough interwoven matrix of collagen and elastin with blood and nerve supply, important in injury as causes gaping of wounds due to elasticity
what is the dermis called in the hoof and horn?
corium
what is the epidermis made of?
4 layers of stratified squamous cells: stratum basale, stratum spinosum, stratum granulosum, stratum corneum
describe stratum basale
folded and germinal
describe stratum spinosum
shrunken, retain desmosomes between cells
describe stratum granulosum
has keratinisation
describe stratum corneum
has shrunken nuclei and lots of keratin, surface layer of skin, shed into environment as squames
how thick is epidermis on flank?
20 um
how thick is epidermis on nose?
600 um
how thick is epidermis on pads?
1800 um
does epidermis have direct blood supply?
no
is epidermis innervated?
only by very tips of sensory nerves
what are melanins?
polymers of indoles with side chains
what are the two types of melanin?
eumelanin (black/brown) and phaeomelanin (red/yellow)
what does the pad of a dog paw have?
conical papillae
what are melanocytes derived from?
neural crest
what are melanocytes stimulated by?
melanocyte stimulating hormones α,β,γ
how does UV light lead to increased melanogenesis?
causes DNA damage leading to pyrimidine fragments
what muscle in the ectoderm contracts the hair follicle?
arrector pili muscle
what is the technical term for whiskers?
vibrissae
what are the types of sebaceous gland? (3)
simple, specialised, scent
what is the function of simple sebaceous glands?
secrete sebum/lanolin which keeps skin pliable, waterproof and water repellent
what glands secrete ear wax?
ceruminous (specialised sebaceous)
what scent glands do ruminants have? (4)
caudal horn, preorbital, interdigital, inguinal
what scent glands do pigs have?
preputial and carpal
what scent glands do rabbits have?
inguinal and chin
what scent glands do carnivores have? (5)
dorsal tail (dog), circumoral (cat), circumanal, paranal, anal
what are the paranal sacs called?
anal glands
what are the types of sweat glands?
apocrine, mammary, eccrine, venom
