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35 Cards in this Set
- Front
- Back
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integument |
often considered an organ in its own right performs a number of vital functions for the body |
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functions of integument (all fourteen) |
- holds underlying organs in place - points for muscle attachment - frictional surface to grip objects in environment - protects underlying tissues by absorbing friction - barrier to pathogens, free flow of water/ions, and free flow of gases - thermoregulation - protection from solar radiation - sensory organ - communication - accessory locomotion structures, feeding structures - defense from predators/dominance over competitors |
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structure of integument |
three layers of tissue: - epidermis - dermis - hypodermis |
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structure of epidermis |
- stratified squamous epithelium - composed of keratinocytes (keratin is a water resistant protein) - epidermal cells produced by mitotic division of cells in the stratum germinativum - new cells are produced, old cells pushed outward |
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keratinization |
w/in epidermis
process of secreting increasing quantities of keratin in outermost cell layers of epidermis |
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dermis basic definition |
dense, irregular connective tissue may be layered with fibers parallel within layers called Plies warp (longitudinal) and weft (cross fibers) arrangement in a bias direction - 45 deg from longit |
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dermis structure |
contains: - blood vessels - nerve fibers - sensory structures - glands - bones (scales/osteoderms) - chromatophores |
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hypodermis structure |
contains loose areolar connective tissue called fascia, which are composed of collagen/elastic fibers |
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development of integument |
(in vert. embryos epidermis) = single epithelium by neurula stage cells undifferentiated; dermis arises from the dermatome neural crest cells migrate between two layers to produce chromatophores and osteoderms |
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phylogenic differentiation of integument: amphioxus |
epidermis is simple columnar epithelium; cells secrete mucous & pigment; dermis consists of thin layer of connective tissue |
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phylogenic differentiation of integument: fish |
epidermis is stratified epithelium outer cells usually not keratinized but active living cells; two cells types: epithelial cells and unicellular mucous glands skin covered by a mucous cuticle |
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unicellular glands in fish |
thread cells: hagfish club cells: alarm response in fish (lamprey&up) granular cells: secretes mucous (lamprey&up) goblet cells: secretes mucous (not lamprey) multicellular slime glands: hagfish |
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chromatophores |
pigment bearing cells melanophore: produces melanin, has long cellular extensions - melanosomes: organelles that contain melanin iridophore: contain reflective platelets of guanine that produce shiny/silver appearance xanthophores/erythophores: contain yellow/red pigments (respectfully) photophore: glands that produce light |
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mechanisms for concealing photophores (flashlight fish) |
- combination - rotating - shuttering |
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coloration cryptic vs. aposematic |
cryptic: camouflage, used to conceal an animal in its native habitat aposematic: warning coloration, used to warn a predator of noxious qualities |
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scales |
bony structures produced largely by the dermis; only ectodermal contribution is when scales have an enamel covering (placoid) composed of true bone with some layers of enamel and/or dentine |
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what was the most primitive bony scale and who whas it on? |
cosmoid plates on extinct agnathans such as heterostracans contained basal layer of lamellar bone ; layer of cavernous bone ; denticle of cosmine (dentine) ; enameloid substance (ganoine) |
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integument structure amphibian |
larval skin is smiliar to fish ; few epidermal layers and no keratin after metamorphosis, more layers are added and some keratin later dermis highly vascularized = moist skin as secondary respiratory organ (only resp. organ in lungless salamanders) |
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integument structure reptiles |
stratum corneum becomes many layers thick outer layers keratinize & bound with phospholipids to impede water loss contain soft alpha keratin and hard beta keratin |
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integument structure reptiles squamates (snakes/lizards/amphisbaenia) |
complex double layer of epidermis develops layers: outer epidermal generation = dead keratin cells inner epidermal generation = active living cells during shedding, intervening cells self destruct allowing outer layer to shed in one/few pieces |
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coossification |
skin + underlying bone = unique dermal ornamentation may help reduce water loss |
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epidermal derivates reptiles |
claws & beaks = highly cornified outer epidermis impregnated w/ calcium salts to increase hard/brittleness glandularization is reduced |
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epidermal derivates reptiles birds |
thin, delicate epidermis - most of skin protected by feather allow precise thermoregulation and function as a flight surface trap layer of air against body to provide insulation |
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feather structure |
"modified reptilian scales" implanted in a follicle in the dermis bottom hollow root = calamus supports lateral vanes composed of tiny straight barbs ; neighbor barbs interlock and = barbules |
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feather structure development |
develop from dermal papilla begins with feather sheath ; sinks into a follicle nearly mature: sheath reptures, feather unfurls & barbs released molted every 6 - 12 months |
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feather structure big picture |
follicles arranged in tracts called pterylae brood patch: featherless skin becomes highly vascularized during nesting season main skin gland = uropygial gland: secretes fatty/oil material birds spread via beak during preening ; helps w/ waterproofing |
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epidermal derivatives
marine birds |
albatrosses & petrels specialized salt glands on head = can drink salt water |
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integument structure mammals |
epidermis: thick and multilayer (< palms + soles) dermis: arrector pili (smooth muscles), blood vessels, hair follicles, invaginated glands, & sensory nerves foot pads of many mammals have exceptionally thick layers of epi/dermis |
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epidermal derivations mammals hair |
not homologous to reptile scales ; novel derivation primarily thermoregulatory in function ; can perform specific others: guard hair ; mane ; quills ; underfur ; vibrissae |
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epidermal derivations mammals hair structure |
single hair has hollow, inner medulla and scaly outer surface ; composed of a shaft and swollen base called a bulb that hugs dermal papilla around hair cortex is the epithelial / connective tissue root sheath all of this is dead; hair is compacted, cornified keratinocytes production of new cells by papilla = continuous growth of shaft follicle has sebaceous gland ; arrector pili (smooth muscle) ; hair plexus (nerve ending) ; apocrine sweat gland nearby |
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epidermal derivations mammals claws |
tough dorsal unguis spongy ventral subunguis growth results from cell division w/in the matrix specialized modifications include hoofs and fingernails |
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epidermal derivations mammals glands |
sebaceous: produces sebum (oil) sudoriferous: produces sudor (swear) *two types most abundant & widespread in humans/chimps platypus: only on snout ; cats/rats/mice: paws deer: base of tail ; rabbits: lips |
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epidermal derivations mammals glands two types od sudoriferous (sweat) gland |
eccrine: thin, watery sweat ; improves grip at frictional surfaces ; lubricates sensory surfaces (snout) ; evaporative cooling apocrine: function in release of pheromones ; only found in axillary & inguinal regions (after puberty) |
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epidermal derivations mammals glands mammary |
characteristics of both sebaceous + apocrine glands produce milk = nutrition of offspring defining feature of mammalia |
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mammary glands structure |
three basic configurations: breast + nipple ; teat ; monotremes B+N: open separately at surface of a nipple (all epidermis) teat: ducts open into common chamber called cistern (found in ungulates) monotremes: glands open into shallow depression on the belly that contain hair; young lap milk from hairs (in both males and females have) |
