The Epidermis

1
The Epidermis
Epidermis of aquatic organisms Cornified
structures include -______ of lamprey and
hagfish -____________________of land-going
amphibians -_________ of tadpoles -Distal
2
The Epidermis
Epidermis of terrestrial organisms Stratified
layers gave rise to 2 categories of unique
features 1) Glands 2) Stratum corneum
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The Epidermis
Epidermis of terrestrial organisms Glands fall
in 2 main categories based on shape 1) 2)
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The Epidermis
Epidermis of terrestrial organisms Glands
produce their secretions via 3 main modes 1)
Cell membrane (_____________) 2) Whole cells and
their contents (_____________) 3) Cell fragments
(_____________)
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The Epidermis
Epidermis of terrestrial organisms Mucous glands
not abundant occur in areas with need for
lubrication Why not abundant on terrestrial
animals? What other skin structures would
interfere? What areas need lubrication?
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The Epidermis
Epidermis of terrestrial organisms Granular
glands found mainly in terrestrial amphibians and
reptiles Can produce ____________ and some
____________________ Concentrations of noxious
granular glands found on warts and
___________________of toads Lizards have
___________________ Musk or ________________ in
turtles and snakes
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The Epidermis
Epidermis of terrestrial organisms (birds) Few
integumentary glands in birds however, avian oil
glands _______________ gland at rump, large in
aquatic birds and some domestic birds Oil glands
also line Sometimes found around the
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The Epidermis

• Epidermis of terrestrial organisms (mammals)
• 2 major types of glands in mammals
• (oil glands)
• 2) (sweat
  glands)

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The Epidermis
Epidermis of terrestrial organisms
(mammals) _________________(saccular) usually
associated with hair. Exceptions... Sebum
secreted into hair follicle Modified
(_______________) in ear canal to secrete
_______ ___________________ keep conjuctiva moist
(plugged ________________)
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The Epidermis
Epidermis of terrestrial organisms
(mammals) _________________________ (coiled
tubular glands) Evaporative cooling primary
function of _________ sweat glands Found in least
hairy regions Some mammals lack sweat
glands Humans have greatest per cm2 ___________
sweat glands involved with secondary sex
characteristics
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The Epidermis
Epidermis of terrestrial organisms
(mammals) Scent glands can be sebaceous or
sudoriferous Found in varying locations - - -
- - -
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The Epidermis
Epidermis of terrestrial organisms
(mammals) ___________________ present in both
sexes and derived from a line of ectoderm called
the _____________________ This tissue invades the
dermis and spreads Distinct tissue above these
glands develops (____________)
http//en.wikipedia.org/wiki/ImageIllu_breast_ana
tomy.jpg
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The Epidermis
Epidermis of terrestrial organisms
(mammals) Nipples can be multiple - - - -
Different species different placement
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The Epidermis
Epidermis of terrestrial organisms
(mammals) During lactation, products accumulate
in _____________ (usually) Suckling releases
_____ and _____________ facilitates by causing
smooth muscle contractions _____________ reflex
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The Epidermis
Stratum corneum Epidermal scales found only in
_____________. Squamates (snakes lizards)
thickened corneum except at Varying forms
_________, ____, __________, _________ Birds
have epidermal scales on areas lacking
feathers What about mammals?
http//www.richard-seaman.com/USA/States/Nevada/Va
lleyOfFire/Sampler/HornedLizard.jpg
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The Epidermis
Stratum corneum
Thick skin
17
The Epidermis
Claws, hoofs and nails Claws appeared in basal
amniotes Tigers have claws are they homologous
to those of Idaho Giant Salamanders?
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The Epidermis
Claws, hoofs and nails Claws, nails and hooves
homologous Similar structure Birds can
have claws on wings too Are claws shed or worn
down?
http//anatomy.iupui.edu/courses/histo_D502/D502f0
4/lecture.f04/integument.f04/nail.jpg
http//www.science-art.com/gallery/170/170_8212006
165155.jpg
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The Epidermis
Feathers 3 basic types Feathers
comprised of a quill (_________), _____ and
________. Parallel extensions from the shaft
barbs are crosslinked with ________ (hooklets and
flanges)
http//www.explorebiodiversity.com/BIRDS/Adaptatio
ns/pics/featherstypes.jpg
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The Epidermis
Feather development _____________induces
overlying ____________ to divide mitotically
resulting bump is called _____________________ Why
is presence of papillary vasculature
important? Tall columns form a _______________and
push toward tip, becoming barbs
http//cache.eb.com/eb/image?id1712rendTypeId4
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The Epidermis
Feather development When the barbs are still in
protective feather sheath it is called a
________________ At feather maturity bulk of
papilla dies back Basale tissue retracts and then
starts over again Developing feathers push old
feathers out _____________________
http//climate.uvic.ca/people/ewiebe/eggs/09_may_1
.jpg
http//www.catsandcritters.com/newsletter.php
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The Epidermis
http//www.gavinrymill.com/dinosaurs/feathers/sino
sauropteryx2.jpg
Feather origins One hypothesis is that they are
derived from reptile scales Sinosauropteryx Early
development of dermal papilla is similar but
remaining scenario is not Some propose they are
novel structures
http//www.prehistoria.piwko.pl/Obrazki/sinosaurop
teryx2.jpg
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The Epidermis
http//www.brownlog.dreamhost.com/scrapbook/1998_0
9_tacoma/zoo_walrus.jpg
Hair Functions of hair _________________
(underfur and guard hairs) __________(vibrissae) _
_________ (spines and quills)
http//brotherpeacemaker.files.wordpress.com/2008/
10/pitbull_v_porcupine-1.jpg
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The Epidermis
Hair morphology Similar to feathers in that
there is a ___________ __________has ________
__________ with much mitosis __________is portion
under the dermis where cells are
dying __________is portion of hair that is
separate from follicle wall
http//www.haircolorpros.com/images/science_hair1.
gif
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The Epidermis
Hair morphology Thin outer covering is the
___________ Underlying zone called
___________ Inner pith is the ________ Smooth
muscle associated with the follicle and
originating in the dermis is the ______________
http//www.asylumresearch.com/Gallery/FeaturedScie
nce/Hair!.jpg
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The Epidermis
Horns
http//www.skullsunlimited.com/graphics/pronghorn_
skull.jpg
http//animaldiversity.ummz.umich.edu/site/resourc
es/phil_myers/horns_antlers/giraffe.jpg/thumbnail.
jpg
http//www.oucom.ohiou.edu/dbms-witmer/images/Rhin
o_horn_UV_large.jpg
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The Epidermis
Baleen and miscellaneous Toothless whales
(mysteceti) rely on __________ to filter fish
and/or crustaceans (krill)
http//www.coreresearch.org/images/baleen2.jpg
http//anthro.palomar.edu/primate/images/gelada_ba
boon_showing_ischial_callosities.jpg
http//courses.washington.edu/vertebra/452/photos/
diapsids/rattlesnake_rattle.jpg
http//www.peteducation.com/images/articles/tfh_cr
usty_footpads.jpg
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Integuments by Taxa
Agnathans Epidermis stratified, unicellular
glands, mitotically active throughout Dermis
thinner than epidermis but dense/tough
http//wupcenter.mtu.edu/education/Ecology_of_the_
Great_Lakes_03/13lamprey_hickey.jpg
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Integuments by Taxa
Cartilaginous fishes Epidermis stratified,
multicellular glands show up Dermis
______________ and melanophores
http//www.gla.ac.uk/centres/marinestation/researc
h/bask-shark/shark_gape_450.jpg
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Integuments by Taxa
Bony fishes Epidermis many mucous
glands Dermis dermal bone/scales
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Integuments by Taxa
Amphibians Epidermis stratified, multicellular
glands (mucous and granular) Dermis attached to
musculature in some, loose in others, presence of
chromatophores
http//farm1.static.flickr.com/149/415329423_cd21a
eb1cb_o.jpg
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Integuments by Taxa
Non-avian reptiles Epidermis stratified, thick
stratum corneum (scales) Dermis tough, some with
dermal bone
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Integuments by Taxa
Birds Epidermis thin, lacks glands (except
uropygial), modified epidermal layers to form
feathers (scales) Dermis thin, arrector pili
muscles
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Integuments by Taxa
Mammals Epidermis Distinct strata, variety of
glands, hair Dermis exceptionally thick and tough