Transcript Comparative Anatomy Integument Kardong Chapter 6

Comparative Anatomy
Integument
Kardong
Chapter 6
Part 8
Integument
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Epidermis derived from
ectoderm
 Gives rise to glands
Dermis derived from
mesoderm
Figure 8.1.
Figure 8.2. Poisonous Dart Frog.
Figure 8.3. Amphibian skin showing
mucous and poison glands.
Modifications
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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.
Functions of the Skin
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Protection
Respiration
Temperature Control
Nourishment of Young
Locomotion and
reproductive structures
Figure 8.5. African clawed frog (Zenopus laevis)
was used for pregnancy test and spread chytrid
fungus around the world.
Fish Skin
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No stratum corneum
Many unicellular glands
 Like goblet cells,
secretes mucus
Photophores in deep-sea
fishes
Figure 8.6.
Dermal Scales
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Dermal bone plates
became skull surface bones
Ancient armor
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Rhomboid scales
Modern fish
Figure 8.7. Ostracoderm.
Cycloid and ctenoid scales
 Placoid and ganoid scales
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Figure 8.8. Cycloid, ctenoid, placoid, and ganoid scales of modern fish.
Figure 8.9. Derivatives of
primitive dermal bone.
Dermal Scales (cont.’d)
Figure 8.10.
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Ctenoid scales
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Growth rings or annuli
No epidermal scales
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Scales are dermal
Amphibian Skin
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Loses dermal scales
 Exception: Caecilians and some primitive frogs
Epidermal multicellular glands abundant
Stratum corneum (contains Leydig cells to resist entry of
bacteria and viruses)
Fig. 8.11. (book fig. 6.12).
Integumentary Gland Type
Figure 8.12.
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Simple tubular
 Plethodontid mental glands associated with
courtship
Simple coiled tubular
 Sweat glands
Simple branched tubular
 Female plethodontid- spermatheca
Simple alveolar (acinar)
 Mucous glands
Figure 8.13.
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Compound tubular
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Mammary glands of monotremes
Compound branched alveolar
Mammary glands of placentals
 Courtship glands
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Figure 8.14. 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 Salamanders - 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)
Figure 8.15. Salamander spermatophore
(book figure 14.40).
(b)
Figure 8.16. (a) Plethodon (b) spermatophore.
Glands Associated with Mating
(a)
(b)
(c)
Figure 8.17. (a) mental glands, (b) cloaca, (c) nasolabial groove.
Modes of Secretion
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Merocrine
Holocrine
Apocrine
Figure 8.18. Mammalian skin.
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Merocrine
Cell body not injured
 Release particles by
exocytosis
 Most sweat glands in
mammals
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(a)
Holocrine
Cell body discharged with
contents
 Whole cell dies
 Sebaceous glands
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(b)
Figure 8.19. (a) merocrine and
(b) holocrine glands.
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Apocrine
Cellular products gather on
surface then pinched off
 Apical portion pinched off
 Axillary sweat glands
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Figure 8.20. Apocrine gland.
Reptile Skin
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Few glands (dry skin)
Thick stratum corneum
with modifications
Epidermal scales
Figure 8.21. Desert horned lizard.
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Some reptiles have
remnants of dermal
armor (osteoderms)
Osteoderms beneath some
epidermal scales
 Gastralia- large
osteoderms
Figure 8.22. Osteoderms (dermal plates) of
alligator.
 Alligator and skinks
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True dermal bones
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Turtles
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 8.23. Turtle shell.
Reptile Skin
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Turtles have epidermal
scutes- large epidermal
scales
(a)
Snakes have scutes on belly
Spikes and spines are
epidermal
(b)
Figure 8.24. 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
Many lizards and snakes
have scent or cloacal
glands
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Figure 8.25.
Prairie
Rattlesnake.
Snakes use forked tongue
to pick up scent
(Jacobson’s organ)
Figure 8.26.
Jacobson’s
organ.
Musk Glands
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Scent glands
Along carapace in turtles
- Rathke’s glands
Under lower jaw in crocodiles
Musk deer
 Take secretions to make perfume
Fig. 8.27. Turtle
Rathke’s glands.
Skin of Birds
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Few epidermal scales
 Legs and beak
Dermal scales are absent
Claws- diversified
Few glands
 Uropygial glandpreening gland
Dermal scales absent
Figure 8.28. Feather type (see book figure 6.15).
Feathers
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Modification of reptilian scales
3 types
 Contour- flight feather
 provides wing shape
 Down- beneath contour
feather
 Filoplume- long shaft
 lost its vane
Figure 8.29.
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
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Figure 8.30. Vibrissae of harbor seal.
Skin of Mammals (cont’d.)
Figure 8.31. Cross sections of mammalian
skin.
Cornified Structures
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Baleen Plate
Toothless whale’s horny
sheets of oral ectoderm
 Not bone
 Used for filter feeding
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Tori pads
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Epidermal pads
Figure 8.32. Products of stratum corneum; tori.
Horns
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Horns
In bovid family
 Outgrowth of dermal
core
 Unbranched
 Covered by epidermal
horny, keratinized
sheath
 Permanent
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Figure 8.33. Bovine horn.
Antlers
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Antlers and horns of
giraffe
Deer
 Dermal bones
 Dermal bone of antler
attaches to skull bone
 Shed annually
 Outside layer is highly
vascularized
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Figure 8.34. Antler.
Figure 8.35. (a) horns and (b) antlers
(see book figure 6.26).
Dermal Pigments
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Chromatophores
contain pigment granules
 Melanophores (brown)
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Melanin granules within melanosomes
Lipophores (yellow and red)
 Iridophores or guanophores (iridescent)
- Contain reflective guanine crystals
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