1. Comparative Anatomy Integument
Kardong
Chapter 6
Part 8

2. Integument Epidermis derived from ectoderm Gives rise to glands
mesoderm
Figure 8.1.

3. Figure 8.3. Amphibian skin showing mucous and poison glands.
Figure Poisonous Dart Frog.

4. Modifications Presence or absence of bone in dermis
Glands in aquatic forms
Specializations in epidermis of land dwellers
Figure African hairy frog with specialized hairs acting as auxiliary respirator organs.

5. Functions of the Skin Protection Respiration Temperature Control
Nourishment of Young
Locomotion and reproductive structures
Figure African clawed frog (Zenopus laevis) was used for pregnancy test and spread chytrid fungus around the world.

6. Fish Skin No stratum corneum Many unicellular glands
Like goblet cells,
secretes mucus
Photophores in deep-sea
fishes
Figure 8.6.

7. Dermal Scales Dermal bone plates became skull surface bones
Ancient armor
Rhomboid scales
Modern fish
Cycloid and ctenoid scales
Placoid and ganoid scales
Figure Ostracoderm.
Figure Cycloid, ctenoid, placoid, and ganoid scales of modern fish.

8. Figure 8.9. Derivatives of primitive dermal bone.

9. Dermal Scales (cont.’d)
Figure 8.10.
Ctenoid scales
Growth rings or annuli
No epidermal scales
Scales are dermal

10. Amphibian Skin 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 (book fig. 6.12).

11. Integumentary Gland Type
Figure 8.12.
Simple tubular
Plethodontid mental glands associated with courtship
Simple coiled tubular
Sweat glands
Simple branched tubular
Female plethodontid- spermatheca
Simple alveolar (acinar)
Mucous glands

12. Compound branched alveolar
Figure 8.13.
Compound tubular
Mammary glands of monotremes
Compound branched alveolar
Mammary glands of placentals
Courtship glands

13. (a) Simple tubular, (b) Coiled tubular,
Figure 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

14. Plethodontid Salamanders - Mating
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 Salamander spermatophore
(book figure 14.40).
(b)
Figure (a) Plethodon (b) spermatophore.

15. Glands Associated with Mating
(b)
(c)
Figure (a) mental glands, (b) cloaca, (c) nasolabial groove.

16. Modes of Secretion Merocrine Holocrine Apocrine
Figure Mammalian skin.

17. Merocrine Holocrine Cell body not injured
Release particles by exocytosis
Most sweat glands in mammals
Holocrine
Cell body discharged with contents
Whole cell dies
Sebaceous glands
(a)
(b)
Figure (a) merocrine and
(b) holocrine glands.

18. Apocrine Cellular products gather on surface then pinched off
Apical portion pinched off
Axillary sweat glands
Figure Apocrine gland.

19. Reptile Skin Few glands (dry skin)
Thick stratum corneum with modifications
Epidermal scales
Figure Desert horned lizard.

20. Some reptiles have remnants of dermal armor (osteoderms)
Osteoderms beneath some epidermal scales
Gastralia- large osteoderms
Alligator and skinks
True dermal bones
Turtles
Figure Osteoderms (dermal plates) of alligator.

21. Turtles Shell of dermal bone Carapace (shell) – dorsal
Plastron- ventral
Mesoplastron additional bone on primitive, extinct turtles
Nuchal- diagnostic bone
Figure Turtle shell.

22. Reptile Skin Turtles have epidermal scutes- large epidermal scales
Snakes have scutes on belly
Spikes and spines are epidermal
(a)
(b)
Figure Snake belly scutes (a) and white bony plate of turtle with scutes removed.

23. Reptile Integumentary Glands
Femoral pores
Occur ventrally, waxy excretion
Many lizards and snakes have scent or cloacal glands
Snakes use forked tongue to pick up scent (Jacobson’s organ)
Figure Prairie Rattlesnake.
Figure Jacobson’s organ.

24. Musk Glands Scent glands Along carapace in turtles - Rathke’s glands
Under lower jaw in crocodiles
Musk deer
Take secretions to make perfume
Fig Turtle
Rathke’s glands.

25. Skin of Birds Few epidermal scales Legs and beak
Dermal scales are absent
Claws- diversified
Few glands
Uropygial gland- preening gland
Dermal scales absent
Figure Feather type (see book figure 6.15).

26. Feathers 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.

27. Skin of Mammals Modifications of stratum corneum Hair Vibrissae
Hair, claws, nails, hooves
Hair
Like filoplume feather and
lack detail
Vibrissae
Specialized hairs
Tactile in function
Figure Vibrissae of harbor seal.

28. Skin of Mammals (cont’d.)
Figure Cross sections of mammalian
skin.

29. Cornified Structures Baleen Plate Tori pads
Toothless whale’s horny sheets of oral ectoderm
Not bone
Used for filter feeding
Tori pads
Epidermal pads
Figure Products of stratum corneum; tori.

30. Horns Horns In bovid family Outgrowth of dermal core Unbranched
Covered by epidermal horny, keratinized sheath
Permanent
Figure Bovine horn.

31. 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 Antler.

32. Figure 8.35. (a) horns and (b) antlers
(see book figure 6.26).

33. Dermal Pigments Chromatophores contain pigment granules
Melanophores (brown)
Melanin granules within melanosomes
Lipophores (yellow and red)
Iridophores or guanophores (iridescent)
- Contain reflective guanine crystals