Transcript Comparative Anatomy - Arkansas State University

Comparative Anatomy
Integument
Note Set 6
Chapter 6
Integument
Figure 8.1

Epidermis derived from ectoderm


Gives rise to glands
Dermis derived from mesoderm
Figure 8.2: Poisonous Dart Frog.
Figure 8.3: Amphibian skin showing
mucous and poison glands.
Modifications



Presence or absence of
bone in dermis
Glands in aquatic forms
Specializations in
epidermis of land
dwellers
Figure 8.4: African hairy frog with
specialized hairs acting as auxiliary
respirator organs.
Function of Skin





Protection
Respiration
Temperature Control
Nourishment of Young
Locomotion and
reproductive structures
Figure 8.5: African clawed frog (Xenopus laevis) was
used for pregnancy test and spread chytrid fungus
around the world.
Fish Skin


No stratum corneum
Many unicellular glands

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Like goblet cells, secretes mucus
Photophores
Dermal Scales


Dermal bone plates
became skull
Ancient armor
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Rhomboid scales
Modern fish
Figure 8.6
Cycloid and ctenoid scales
 Placoid and ganoid scales

Figure 8.7: Cycloid, ctenoid, placoid, and ganoid scales of modern fish.
Figure 8.8: Derivatives of
primitive dermal bone.
Dermal Scales
Figure 8.9
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Ctenoid scales
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Growth rings or annuli
Fish have no epidermal scales
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Scales are dermal
Amphibian Skin
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Loses dermal scales
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Exception: caecilian
Epidermal multicellular glands abundant
Stratum corneum
Integumentary Gland Type
Figure 8.10
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Simple tubular
 Plethodontid mental glands associated with
courtship glands
Simple coiled tubular
 Sweat glands
Simple branched tubular
 Female plethodontid- spermatotheca
Simple alveolar (acinar)
 Mucous glands
Figure 8.11

Compound tubular


Mammary glands of monotremes
Compound branched alveolar
Mammary glands of placentals
 Courtship glands

Figure 8.12: Morphological varieties of multicellular glands.
(a) Simple tubular, (b) Coiled tubular,
(c) Simple branched tubular, (d) Compound tubular,
(e) Alveolus of simple saccular gland, (f) Simple branched saccular,
(g) Compound alveolar
Plethodontid (lungless salamander) Mating

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Internal fertilization
Male: mental glands on
chin, cloacal glands to form
spermatophore, and caudal
courtship glands
Female: spermatheca for
sperm storage
Glands secrete pheromones
(a)
(b)
Figure 8.13: (a) Plethodontid sal. (b) spermatophore.
Mating
(a)
(b)
(c)
Figure 8.14: (a) mental glands, (b) cloaca, (c) nasolabial groove.
Modes of Secretion

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Merocrine
Holocrine
Apocrine
Figure 8.15

Merocrine
Cell body not injured
 Release particles by exocytosis
 Most sweat glands in mammals

(a)

Holocrine
Cell body discharged with
contents
 Whole cell dies
 Sebaceous glands

(b)
Figure 8.16: (a) merocrine and
(b) holocrine glands.

Apocrine
Cellular products gather on
surface then pinched off
 Apical portion pinched off
 Axillary sweat glands

Figure 8.17: Apocrine gland.
Reptile Skin
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Few glands (dry skin)
Thick stratum corneum
with modifications
Epidermal scales
Figure 8.18: Desert horned lizard.

Some reptiles have
remnants of dermal armor
(osteoderms)
Osteoderms beneath some
epidermal scales
 Gastralia- large osteoderms
 Alligator and skinks
Figure 8.19: Osteoderms (dermal plates) of


True dermal bones

Turtles
alligator.
Turtles
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Shell of dermal bone
Carapace (shell) – dorsal
Plastron- ventral

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Mesoplastron additional bone on
primitive, extinct turtles
Nuchal- diagnostic bone
Figure 8.20
Reptile Skin



Turtles have epidermal
scutes- large epidermal scales
Snakes have scutes on belly (a)
Spikes and spines are
epidermal
(b)
Figure 8.21: snake belly scutes (a) and white
bony plate of turtle with scutes removed.
Reptile Integumentary Glands
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Femoral pores
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Occur ventrally, waxy
excretion
Figure 8.22:
Prairie
Rattlesnake.
Many lizards, turtles and
snakes have scent or
cloacal glands

Snakes use forked tongue
to pick up scent (Jacobson’s
organ)
Figure 8.23:
Jacobson’s
organ.
Musk Glands
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
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Scent glands
Along carapace in turtles
Under lower jaw in crocodiles
Musk deer
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Take secretions to make perfume
Skin of Birds
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Few epidermal scales

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
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Dermal scales are absent
Claws- diversified
Few glands

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Legs and beak
Uropygial gland- preening
gland
Dermal scales absent
Figure 8.24: Feather type.
Feathers

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Modification of reptilian scales
3 types

Contour- flight feather

provides wing shape
Down- beneath contour feather
 Filoplume- long shaft

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lost its vane
Skin of Mammals
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Modifications of stratum corneum
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Hair
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Hair, claws, nails, hooves
Like filoplume feather and
lack detail
Vibrissae
Specialized hairs
 Tactile in function

Figure 8.25: Vibrissae of harbor seal.
Cornified Structures

Baleen Plate
Toothless whale’s horny
sheets of oral ectoderm
 Not bone
 Used for filter feeding

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Tori pads

Epidermal pads
Figure 8.26: Products of stratum corneum—tori.
Horns

Horns
In Bovine family
 Outgrowth of dermal
core
 Unbranched
 Covered by epidermal
horny, keratinized sheath
 Permanent

Figure 8.27: Bovine horn.
Antlers

Antlers and horns of
giraffe
Deer
 Dermal bones
 Dermal bone of antler
attaches to skull bone
 Shed annually
 Outside layer is highly
vascularized

Figure 8.28: Antler.
Figure 8.29: (a) horns and (b) antlers.
Dermal Pigments

Chromatophores
contain pigment granules
 Melanophores (brown)
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Melanin granules
Lipophores (yellow and red)
 Iridophores or guanophores (iridescent)
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Contain reflective guanine crystals
Literature Cited
Figure 8.1- http://www.homestead.com/doctorderm/skinanatomy.html
Figure 8.2- http://www.allercafoundation.org/animal16.html
Figure 8.3 & 8.29- Kardong, K. Vertebrates: Comparative Anatomy, Function, Evolution.
McGraw Hill, 2002.
Figure 8.4- http://markmlucas.com/Amphibgallery%20frogs.htm
Figure 8.5- http://www.exn.ca/Stories/1998/05/22/58.asp
Figure 8.6- http://people.eku.edu/ritchisong/342notes1.htm
Figure 8.7- http://www.amonline.net.au/fishes/what/scales/
Figure 8.8, 8.12 & 8.26- Kent, George C. and Robert K. Carr. Comparative Anatomy of the
Vertebrates. 9th ed. McGraw-Hill, 2001.
Figure 8.9- http://people.eku.edu/ritchisong/342notes2.htm
Figure 8.10 & 8.11- http://www.mhhe.com/biosci/ap/histology_mh/glands.html
Figure 8.13 (a)- http://www.invasiveplants.net/images/j2.jpg
Figure 8.13 (b)- http://www.batraciens-reptiles.com/page-salamandres.htm
Figure 8.14- http://www.caudata.org/cc/articles/sexing.shtml#glossary
Figure 8.15http://pharma.kolon.co.kr:8080/test/newstopic/main_contents.jsp?seq=241&no=583
Literature Cited
Figure 8.16 & 8.17- http://www.mhhe.com/biosci/ap/histology_mh/glands.html
Figure 8.18- http://www.richard-seaman.com/Reptiles/Usa/PhotoGalleries/
Figure 8.19- http://science.howstuffworks.com/alligator2.htm
Figure 8.20- http://www.palaeos.com/Vertebrates/Units/Unit200/300.html
Figure 8.21 (a)- http://museum.gov.ns.ca/mnh/nature/snakes/sfacts.htm
Figure 8.21 (b)- http://www.biosbcc.net/ocean/marinesci/05nekton/mtintro.htm
Figure 8.22- http://www.sdsnake.com/Rat.htm
Figure 8.23- http://www2.worldbook.com/features/reptiles/html/body_senorg.html
Figure 8.24- http://www.zoo.ufl.edu/courses/vertzoo/lab_birds.html
Figure 8.25- http://www.seaworld.org/infobooks/HarborSeal/hssenses.html
Figure 8.27http://trc.ucdavis.edu/mjguinan/apc100/modules/Integument/horn/horn1/horn.ht
ml
Figure 8.28http://trc.ucdavis.edu/mjguinan/apc100/modules/Integument/horn/antler1/antler.h
tml