Comparative AnatomyComparative AnatomyIntegumentIntegument
Kardong Kardong Chapter 6Chapter 6
Part 8Part 8
IntegumentIntegument
Epidermis derived from Epidermis derived from ectodermectoderm Gives rise to glands Gives rise to glands
Dermis derived from Dermis derived from mesodermmesoderm
Figure 8.1.
Figure 8.3. Amphibian skin showing mucous and poison glands.
Figure 8.2. Poisonous Dart Frog.
ModificationsModifications
Presence or absence of Presence or absence of bone in dermisbone in dermis
Glands in aquatic formsGlands in aquatic forms Specializations in epidermis Specializations in epidermis
of land dwellersof land dwellers
Figure 8.4. African hairy frog with specialized hairs acting as auxiliary respirator organs.
Functions of the Skin Functions of the Skin
ProtectionProtection RespirationRespiration Temperature ControlTemperature Control Nourishment of YoungNourishment of Young Locomotion and Locomotion and
reproductive structuresreproductive structures
Figure 8.5. African clawed frog (Zenopus laevis) was used for pregnancy test and spread chytrid
fungus around the world.
Fish SkinFish Skin No stratum corneumNo stratum corneum Many unicellular glandsMany unicellular glands
Like goblet cells, Like goblet cells, secretes mucussecretes mucus
Photophores in deep-sea Photophores in deep-sea fishes fishes
Figure 8.6.
Dermal Scales Dermal Scales Dermal bone plates Dermal bone plates
became skull surface bonesbecame skull surface bones Ancient armorAncient armor
Rhomboid scalesRhomboid scales Modern fishModern fish
Cycloid and ctenoid scalesCycloid and ctenoid scales Placoid and ganoid scalesPlacoid and ganoid scales
Figure 8.8. Cycloid, ctenoid, placoid, and ganoid scales of modern fish.
Figure 8.7. Ostracoderm.
Figure 8.9. Derivatives of primitive dermal bone.
Dermal Scales (cont.’d)Dermal Scales (cont.’d)
Ctenoid scalesCtenoid scales Growth rings or annuliGrowth rings or annuli
No epidermal scalesNo epidermal scales Scales are dermalScales are dermal
Figure 8.10.
Amphibian SkinAmphibian Skin Loses dermal scalesLoses dermal scales
Exception: Caecilians and some primitive frogsException: Caecilians and some primitive frogs Epidermal multicellular glands abundantEpidermal multicellular glands abundant Stratum corneum (contains Leydig cells to resist entry of Stratum corneum (contains Leydig cells to resist entry of
bacteria and viruses)bacteria and viruses)
Fig. 8.11. (book fig. 6.12).
Integumentary Gland Type Integumentary Gland Type
Simple tubularSimple tubular Plethodontid mental glands associated with Plethodontid mental glands associated with
courtshipcourtship Simple coiled tubularSimple coiled tubular
Sweat glandsSweat glands Simple branched tubularSimple branched tubular
Female plethodontid- spermathecaFemale plethodontid- spermatheca Simple alveolar (acinar)Simple alveolar (acinar)
Mucous glandsMucous glands
Figure 8.12.
Compound tubularCompound tubular Mammary glands of monotremesMammary glands of monotremes
Compound branched alveolarCompound branched alveolar Mammary glands of placentalsMammary glands of placentals Courtship glandsCourtship glands
Figure 8.13.
(a) Simple tubular, (b) Coiled tubular, (a) Simple tubular, (b) Coiled tubular, (c) Simple branched tubular, (d) Compound tubular, (c) Simple branched tubular, (d) Compound tubular, (e) Alveolus of simple saccular gland, (f) Simple branched saccular, (e) Alveolus of simple saccular gland, (f) Simple branched saccular, (g) Compound alveolar(g) Compound alveolar
Figure 8.14. Morphological varieties of multicellular glands.
Plethodontid Salamanders - MatingPlethodontid Salamanders - Mating Internal fertilizationInternal fertilization Male: mental glands on chin, cloacal glands Male: mental glands on chin, cloacal glands
to form spermatophore, and caudal to form spermatophore, and caudal courtship glandscourtship glands
Female: spermatheca for sperm storageFemale: spermatheca for sperm storage Glands secrete pheromonesGlands secrete pheromones
Figure 8.16. (a) Plethodon (b) spermatophore.
(a)
(b)Figure 8.15. Salamander spermatophore (book figure 14.40).
Glands Associated with MatingGlands Associated with Mating
Figure 8.17. (a) mental glands, (b) cloaca, (c) nasolabial groove.
(a) (b)
(c)
Skin Glands in a SalamanderSkin Glands in a Salamander
Cloacal Glands in a Salamander
Head Glands in a Salamander
Modes of Secretion Modes of Secretion
MerocrineMerocrine HolocrineHolocrine ApocrineApocrine
Figure 8.18. Mammalian skin.
MerocrineMerocrine Cell body not injuredCell body not injured Release particles by exocytosisRelease particles by exocytosis Most sweat glands in mammalsMost sweat glands in mammals
HolocrineHolocrine Cell body discharged with Cell body discharged with
contentscontents Whole cell diesWhole cell dies Sebaceous glandsSebaceous glands
Figure 8.19. (a) merocrine and (b) holocrine glands.
(a)
(b)
ApocrineApocrine Cellular products gather on Cellular products gather on
surface then pinched offsurface then pinched off Apical portion pinched offApical portion pinched off Axillary sweat glands Axillary sweat glands
Figure 8.20. Apocrine gland.
Reptile Skin Reptile Skin
Few glands (dry skin)Few glands (dry skin) Thick stratum corneum Thick stratum corneum
with modificationswith modifications EpidermalEpidermal scales scales
Figure 8.21. Desert horned lizard.
Some reptiles have Some reptiles have remnants of dermal remnants of dermal armor (osteoderms)armor (osteoderms) Osteoderms beneath some Osteoderms beneath some
epidermal scalesepidermal scales Gastralia- large Gastralia- large
osteodermsosteoderms Alligator and skinksAlligator and skinks
True dermal bonesTrue dermal bones TurtlesTurtles
Figure 8.22. Osteoderms (dermal plates) of alligator.
Turtles Turtles Shell of dermal boneShell of dermal bone Carapace (shell) – dorsalCarapace (shell) – dorsal Plastron- ventralPlastron- ventral
Mesoplastron additional bone on Mesoplastron additional bone on primitive, extinct turtlesprimitive, extinct turtles
Nuchal- diagnostic boneNuchal- diagnostic bone
Figure 8.23. Turtle shell.
Reptile SkinReptile Skin
Turtles have epidermal Turtles have epidermal scutes- large epidermal scutes- large epidermal scalesscales
Snakes have scutes on bellySnakes have scutes on belly Spikes and spines are Spikes and spines are
epidermalepidermal
Figure 8.24. Snake belly scutes (a) and white bony plate of turtle with scutes removed.
(a)
(b)
Reptile Integumentary GlandsReptile Integumentary Glands Femoral pores Femoral pores
Occur ventrally, waxy Occur ventrally, waxy excretionexcretion
Many lizards and snakes Many lizards and snakes have scent or cloacal have scent or cloacal glandsglands Snakes use forked tongue Snakes use forked tongue
to pick up scent to pick up scent (Jacobson’s organ)(Jacobson’s organ)
Figure 8.25. Prairie Rattlesnake.
Figure 8.26. Jacobson’s organ.
Musk GlandsMusk Glands Scent glandsScent glands Along carapace in turtlesAlong carapace in turtles
- Rathke’s glands - Rathke’s glands Under lower jaw in crocodilesUnder lower jaw in crocodiles Musk deerMusk deer
Take secretions to make perfume Take secretions to make perfume
Fig. 8.27. TurtleRathke’s glands.
Skin of Birds Skin of Birds Few epidermal scalesFew epidermal scales
Legs and beak Legs and beak Dermal scales are absentDermal scales are absent Claws- diversifiedClaws- diversified Few glandsFew glands
Uropygial gland- Uropygial gland- preening glandpreening gland
Dermal scales absentDermal scales absent
Figure 8.28. Feather type (see book figure 6.15).
Feathers Feathers Modification of reptilian scalesModification of reptilian scales 3 types3 types
Contour- flight featherContour- flight feather provides wing shapeprovides wing shape
Down- beneath contourDown- beneath contour featherfeather
Filoplume- long shaftFiloplume- long shaft lost its vanelost its vane
Figure 8.29.
Skin of Mammals Skin of Mammals Modifications of stratum corneumModifications of stratum corneum
Hair, claws, nails, hoovesHair, claws, nails, hooves HairHair
Like filoplume feather and Like filoplume feather and lack detaillack detail
VibrissaeVibrissae Specialized hairsSpecialized hairs Tactile in functionTactile in function Figure 8.30. Vibrissae of harbor seal.
Skin of Mammals (cont’d.)
Figure 8.31. Cross sections of mammalianskin.
Cornified StructuresCornified Structures
Baleen PlateBaleen Plate Toothless whale’s horny Toothless whale’s horny
sheets of oral ectodermsheets of oral ectoderm Not boneNot bone Used for filter feedingUsed for filter feeding
Tori padsTori pads Epidermal padsEpidermal pads
Figure 8.32. Products of stratum corneum; tori.
HornsHorns HornsHorns
In bovid familyIn bovid family Outgrowth of dermal Outgrowth of dermal
corecore Unbranched Unbranched Covered by epidermal Covered by epidermal
horny, keratinized horny, keratinized sheathsheath
PermanentPermanentFigure 8.33. Bovine horn.
AntlersAntlers
Antlers and horns of Antlers and horns of giraffegiraffe DeerDeer Dermal bonesDermal bones Dermal bone of antler Dermal bone of antler
attaches to skull boneattaches to skull bone Shed annuallyShed annually Outside layer is highly Outside layer is highly
vascularizedvascularized
Figure 8.34. Antler.
Figure 8.35. (a) horns and (b) antlers Figure 8.35. (a) horns and (b) antlers (see book figure 6.26).(see book figure 6.26).
Dermal Pigments Dermal Pigments
ChromatophoresChromatophores contain pigment granulescontain pigment granules Melanophores (brown)Melanophores (brown)
Melanin granules within melanosomes Melanin granules within melanosomes Lipophores (yellow and red)Lipophores (yellow and red) Iridophores or guanophores (iridescent)Iridophores or guanophores (iridescent)
- - Contain reflective guanine crystals Contain reflective guanine crystals