integument Flashcards
integument
(AKA skin)
covers entire animal, includes sweat and oil glands, hair, nails, horns
integument function
protective (microbes, insects, parasites, environment, chemical, UV, physical) - preventing dehydration body temp regulation - detecting sensory info synthesis of vit D - food gathering (claws)
characteristics of the skin
covers external surface of animals, can heal and regenerate. human skin replaced every 4-7 weeks.
loosely attached to enable movement w/o tearing
thickest where commonly exposed (elbow vs between fingers)
layers of the skin
epidermis
dermis
hypodermis
location of blood cells in integument?
mostly in the hypodermis, w little trails up to the dermis.
no blood in epidermis
epidermis
layer of flat cells, free of nerve endings, gets nutrients through diffusion from the dermis. basal layer (closest to dermis) mostly keratin, cells migrate up where they then kinda shed off.
kertatinization
keratin to epithelium, cornification where superficial cells to stratified epithelium along w hardening and release of glycolypids which slow water loss
function of hertatin
makes skin tough and resistant to drying out
desmosomes
anchors, connects keratinocytes to form a more protective barrier
melanocites
produces pigment, melanin which protects against UV radiation
merkel cells
sensory receptors to light touch
langerhan’s cells
phagocytes foreign debris or microorganisms
- immune cell type
dermis
middle layer
has palpable that projects into the epidermis where they interdigitate w the epidermal projections to cement the 2 layers together
makes up most of the integument
AKA Corium
relationship between epidermis and dermis
folds project down into the dermis
functions of the dermis
- structural strength and flexibility of the skin (bc of collagen and other fibres)
- presence of blood vessels (gives nutrients to epidermis)
- sensory receptors (sends info to CNS)
hypodermis
under the dermis
AKA subcutaneous fat layer
allows skin to move over underlying muscle and bone w/o tearing
cushions and protects skin and underlying muscles and organs
senses in the hypodermis
pacinian corpuscles - touch receptors that respond to heavy pressure and vibrations
blood vessels in the hypodermis
helps w milk production
2 types of sweat glands
eccrine and apocrine
in dermis and hypodermis
what type of glads do farm animals have
apocrine - open into sweat glands
produce secretion w water, fatty acids and proteins combined w gland secretions for the smell
eccrine sweat glands
in primates, secretes mix of water, salts, primary function to cool the body
apocrine glands species differences
horses only animal w large amounts of sweat
bos tarus vs bos indicus, indicus (w the hump) much larger # of sweat glands
pigs dont sweat
oil glands
found all over the body in the dermis, secretes onto the skin surface
oil glands produce sebum
oil glands used to mark territories and attract mates in some species
sebum
like lanolin, keeps hair from being brittle, prevents excess evaporation. keeps skin soft
hair/pilli function
insulation, absorbs light to warm animals, protection via camouflage, also a legit layer
sensory receptors
depends on # and size of follicles on the skin
hair production
occurs at the base of follicle
covered by rapidly dividing cells called the matrix.
get pushed away from papilla and die from lack of nutrients.
layers of dead skin. fun
guard/primary hair
forms smooth outer coat
undercoat
wool hairs (soft and curly) sheep have no guard hairs so their wool is long and fine
innervated tactile hairs
organs of touch (whiskers)
feathers
function to protect against elements, enable flying, maintain body temp, protect from predators, attraction
ungulate
hoofed animal, use tips of toes to sustain entire body weight
what is a hoof anatomically
extension of skin from lower limbs covering distal digit
why shoe horses
increase integrity of hoof wall increase traction strengthens foot prevents expansion of the hoof protective barrier between hoof and ground
horns
over corneal process in frontal skull bones
horn core found on frontal bone
elongates from the base, cells considered epidermal cells
made up of dense keratin similar to hoof wall and hair
what influences horn growth
nutrition
sex
species
genetics
