1. THE INTEGUMENTARY SYSTEM Skin and its Derivatives

5. DIFFERENCES OF THE SKIN LAYERS BASIS EPIDERMIS DERMIS HYPODERMIS 1. LOCATION OUTERMOST SUB EPIDERMAL SUBCUTANEOUS 2.THICKNESS THIN THICK RELATIVE 3. HISTOLOGICAL COMPONENT HIGHLY EPITHELIAL CONNECTIVE, MUSCULAR,NERVOUS, VASCULAR CONNECTIVE 4. VASCULARI- ZATION AVASCULAR VASCULAR VASCULAR

6. 5. LAYERS 5 SUB LAYERS 1.S. CORNEUM 2.S. LUCIDUM 3.S. GRAULOSUM 4. S. SPINOSUM 5. S. GERMINATIVUM 2 SUB LAYERS 1.S. PAPILLAROSUM 2.S. RETICULAROSUM RELATIVE 6. NERVE ENDINGS ABSENT PRESENT PRESENT 7. GLANDS AGLANDULAR GLANDULAR –SWEAT,SEBACEOUS, MAMMARY GLANDULAR – SECRETES LEPTIN 8. DERIVATIVES HAIRS AND NAILS GLANDS GLAND

14. APOCRINE SWEAT GLAND

21. COMPARATIVE ANATOMY OF THE SKIN CHORDATE EPIDERMIS DERMIS 1. AGNATHANS ‘ multi-layered and is rich w/mucous glands ‘ slime eels lack scales ‘ Layers are mitotic including surface cells horny denticles in the buccal funnel is the only cormfied structure,shed replaced ‘ thinner than epidermis but tough due to interwoven collagenous fibers. ‘ rich in the melanophores w/c ad heres tightly to the underlying musculator myosepta

22. CHORDATE EPIDERMIS DERMIS 2.CHONDRICH-THYES ‘ more layered and cells are compactly arranged ‘ unicellular glands excepting chaemiras ‘ stingrays-goblet toxins. ‘ multicellular cells at the base secretes toxins Multicelullar cells are conc. at the base of the claspers of males ‘ thicker than epidermis and w/2 more or less defined layers ‘ placoid scales fr.the paleozioc shakers ‘ sheet of melanophores derse dorsally than virtrally less illumnuscence ‘ with ceratotrichia or fin rays

24. CHORDATE EPIDERMIS DERMIS 3. OSTEICH-THYES -more mucous glands -presence of cycloid scales -with uicellular goblet cells w/c maintain mucous coat of the skin to prevent dessication -with poisonous granular gland -photophores serve as lures /warning -presence of ancient ganoid or modern cycloid scale -flexible dermal fin rays which stregthens the fins of bony fishes -with osteoderms

25. Bony fish

27. CHORDATE EPIDERMIS DERMIS 4.AMPHIBIA ‘ skin-w/o scales ‘ with incipient stratum corneum ‘ uncellular goblet cells secretes mucigens for semi-aquatic amphibians ‘ mucons glands-mucin ‘ poison glands-alkaloidal secreation ‘ cornified skin prevents dessication. ‘ with dermal chomatophores ‘ firmly attached to the underlying musuculature ‘ voluminous bread subcutaneous lymph sinuses separates skin from muscles ‘ bony dermal scales in caecilians

29. CHORDATE EPIDERMIS DERMIS 5.REPTILES ‘ thick stratum corneum ‘ with epidermal scales molts at regular internal ‘ presence of unique horny surface features ‘ integumentary glands are not abundant ‘ scales,scutes,rattles,clansz,plaque,spiny crests ‘ bony dermal,bones are more abundant ‘ osteoderms 1.lizards-underlying the epidermal scales 2.snakes-absent

30. Reptilian

31. CHORDATE EPIDERMIS DERMIS 6.AVES ‘ thin-skinned ‘ epidermal scales umited to feet and base of breaks ‘ presence of sharp clans ‘ integumentary glands are absent ‘ uropygial gland caudal, oil the feathers ‘ with feathers .down .filoplumes .rectrices .remiges ‘ dermis supports the feathers and arrectures pilorum/ plumarun ‘ exceptionally thin ‘ motility of skin is correlated to thermoregulatory function of feathers ‘ no osteoderms ‘ with spurs both sexes .tarsometatasus .carpometasus in some

33. CHORDATE EPIDERMIS DERMIS 7.MAMMALS ‘ hairs are present arising from hair follicles ‘ epidermal glands .sebaceous-sebum .sudoriferous-sweat .mammary-milk ‘ stratum germinativum is germinating ‘ dense stratum corneum ‘ derivatives .claws .horns .hairs .nails .baleen whale bone hangs or oral cavity ‘ presence of hair follicle,arrector muscles,sweat, sebaceous glands,conn. tissues ‘ highly vascularized ‘ with nerve endings ‘ has thermoregulatory function-homiothermic ‘ hypodermis or subcutaneous layer separates skin from muscles ‘ with pigment cells

34. THE MAMMALIAN SKIN

36. Stratum corneum Stratum granulosum Stratum spinosum Stratum basale (germinativum) Stratum lucidum** **Thick skin only

44. Melanocyte

46. Irregular Dense Connective Tissue Collagenous fibers

48. Sweat gland Sebaceous gland Arrector pili muscle Blood vessels

50. FEATURE THIN SKIN THICK SKIN 1. Distribution All parts of the body except palms,palmar digits,soles Palms,palmar surface of digits and soles 2. Epidermal thickness 0.10-0.15mm 0.6 – 4.5 mm 3. Epidermal Strata Lack stratum lucidum,thinner s. spinosum and s. corneum Thick s. lucidum,spinosum,corneum 4. epidermal Ridges Lacking due to poorly developed or fewer dermal papillae Present due to well- developed or numerous dermal papillae 5. Hair follicles and Arrector pili Muscle Present Absent 6. Sebaceous Glands Present Absent 7. Sudoriferpous Gland Fewer More numerous 8. Sensory Receptors Sparser denser

53. Hair Follicle

56. Angora Hair

57. Definitive Hair

58. Lanugo Hair

60. Sebaceous Gland DERIVATIVES OF THE DERMIS

61. Sweat Gland SKIN GLANDS

63. APOCRINE SWEAT GLAND

64. ECCRINE SWEAT GLAND

68. Atlas of Human Anatomy in Cross Section: Section 2. Neck, Shoulders, Upper Arm, and Upper Thorax (Lungs) Key Figure 4 a Ronald A. Bergman, Ph.D., Adel K. Afifi, M.D., Jean J. Jew, M.D., and Paul C. Reimann, B.S. Peer Review Status: Externally Peer Reviewed Recognized by adipose tissue.

70. WHITE SKIN

71. BROWN SKIN