1. Integumentary System Protection & support Sensory Respiratory (amphibians) Thermoregulation – Dissipate heat (blood vessels, sweat) – Conserve heat (blood vessels, hair, feathers)

2. Locomotion Water balance Protective coloring, behavior Vitamin D synthesis

3. Epidermis Ectodermal derivative nonvascular

5. Epidermis Stratum germinativum – Deeper layer – Mitosis

6. Epidermis Superficial layer – Mucus cells (amphibians, fish) – Proteinaceous cells/granular glands Slime, poisons, enamels, photophores, pheromones Keratin (cornified, horny, stratum corneum) – Tetrapod feature

7. Epidermis Glands are epidermal in origin

9. Dermis Dermatome (mesoderm) in origin Lateral/ventral mesoderm Neural crest cells for pigment

11. Dermis Collagen for strength Mucopolysaccharides Elastic fibers Smooth muscle Blood and lymph vessels Follicles and bases of gland

12. Dermis Dermis has ancient potential in forming bone as in this ostracoderm!

13. Hard or Mineralized Tissues Enamel Dentin Bone – Lamellar = Compact – Spongy

16. Hard tissues Bone is very primitive dating back to the ostracoderms

17. Dermis Chromatophores – Dermal in origin – From neural crest cells – Homeotherms have melanophores & pigment is INJECTED into epidermis – Poikilotherms – the pigment stays in the dermis

18. Dermis - Chromatophores Iridophores – silvery & iridescent Xanthophores – yellow Erythrophores - red

19. Fish Skin - Epidermis Cyclostomes – thin with unicellular mucus glands Jawed fish – unicellular mucus glands, no keratin!, photophores in some

21. Fish Dermis Cyclostomes – no scales Ostracoderms & Placoderms – Armor shields

22. Ostracoderm Armor Lamellar bone Spongy bone Dentin(e) Enamel

24. Armor Shield Denticle – Elevations capped with enamel Protection Mineral reservoir

25. Fish Dermis Cosmoid scales Modified dentin layer called Cosmine Extinct sarcopterygians

28. Fish Dermis Ganoid scales Modified thick enamel layer called ganoine Found in gars

31. Ganoid scale

33. Fish Dermis Placoid scales Chondrichthyes Denticle points reduce friction Ancestor to teeth

35. Placoid Scales Dentin Pulp Pulp cavity Epidermis

38. Fish Dermis Modern scales Acellular Thin lamellar bone only Teleosts and modern sarcopterygians Annual rings allows aging of fish

39. Cycloid & Ctenoid Scales

40. Cycloid scale

41. Ctenoid scale

42. Key Points Give two major characteristics of fish skin.

43. Amphibians No scales Multicellular glands (mucus) Stratum corneum – keratin – tetrapod feature

44. Amphibian Epidermis Thin Stratum corneum with keratin Mucus and granular glands

45. IntegumentIntegument DermisDermis EpidermisEpidermis Mucus gland Poison gland

47. Amphibian Dermis Firmly attached May have chromatophores (Caecilians may have bony dermal scales)

49. Key Points Give 2 major characteristics of amphibian skin

50. Reptile Skin THICK stratum corneum Epidermal scales in all Horny (keratinized)surface structures Very few glands, dry skin Some have bony dermal scales or plates

51. ScalesScales EpidermisEpidermis DermisDermis ScaleScale CornifiedlayerCornifiedlayer ChromatophoresChromatophores

52. Reptile epidermis Stratum corneum with keratin Scales Scutes No mucus glands Some have granular/scent glands, but rare

53. ScalesScales EpidermisEpidermis DermisDermis ScaleScale CornifiedlayerCornifiedlayer ChromatophoresChromatophores

60. Reptile Dermis Thin Osteoderms e.g. crocodile Turtle shell – Carapace – Plastron Gastralia – Abdominal “ribs” but dermal scale splints in abdomen of crocodiles

64. Key Points Give 2 major characteristics of reptile skin

65. Bird Skin

66. Thin skin, only thick at foot and beak Loose skin FEATHERS Evolution of feathers

68. Bird Epidermis Thin Horny scales at face, legs, feet Beak Uropygial glands at rump, esp. in aquatic birds

70. Bird Epiderms - Feathers Contour feathers

71. Feathers

73. Shaft – Calamus = Quill – Rachis – vane-bearing part Vane – Barb – Barbule – Hooklet

74. FeathersFeathers ShaftShaft QuillQuill VaneVane

75. Feather structure ShaftShaft BarbBarb HookletsHooklets BarbuleBarbule

76. Bird feathers Preening Rehooks hooklets

77. Bird feathers Down Feathers MAY be ancestral feather Short calamus No hooklets insulation

78. Feathers Contour feathers Down feathers Filoplumes Bristles

79. Bird feathers Feather follicle – ectoderm, but activated by vascular mesoderm Molt is shedding old and growing new feathers

81. Bird Dermis Thin Arrector pullorum muscle Some males have a spur of dermal bone near feet

83. Mammal Skin

84. Mammal skin Hair Glands – a variety Highly keratinized stratified cornified epidermis Thick dermis

85. Mammal Epidermis Stratum germinativum for mitosis Stratum granulosum (one or more layers) Stratum corneum

87. Stratum corneum derivatives Horny scales as in beaver tail Claws, hooves, nails, armadillo shell

91. Stratum corneum derivatives - horns True horns Dermal bony core Horny cover Not shed Ruminants (antelope, cattle)

96. Stratum corneum derivatives - horns Hair horns Rhinoceros

98. Stratum corneum derivatives - horns Antlers & giraffe horns Bone Velvet Antlers (deer, elk, moose) shed but not giraffe horns

104. Mammal Epidermis Glands Sweat Sebaceous Scent Mammary

105. IntegumentIntegument Eccrine sweat gland gland SweatporeSweatpore SebaceousglandSebaceousgland ErectormuscleErectormuscle FollicleFollicle Apocrine sweat gland gland

107. Mammal Epidermis Hairs Origin Shaft – Cortex with cuticle – Medulla

109. Mammal Epidermis - hair Root of hair – Follicle undergoes mitosis – Bulb is widened area in dermis providing nourishment for growing hair Arrector pili muscle

111. Types of hairs Guard hairs

112. Types of hair Underfur

113. Types of hair Vibrissae

114. Types of hair Quills

115. Mammal Dermis Very thick Follicles Arrectors CT Blood vessels Gland bases Nerve endings

118. Key Points Give one major characteristic of bird skin Give one major characteristic of mammal skin

119. Epidermal or Dermal? Sweat gland Hair Fish scale Reptile scale Oil gland