The document discusses the structure, composition, and functions of the integumentary system. It describes the three main layers of skin - the epidermis, dermis, and hypodermis. It details the differences between these layers and lists the skin's main functions like protection, temperature regulation, and sensory functions. The document also examines glands associated with the skin like sweat glands and sebaceous glands. It discusses skin derivatives like hair, nails, scales and compares skin structures across different chordates.

1. THE INTEGUMENTARY SYSTEM Skin and its Derivatives

2. DERMATOLOGY STUDY OF THE STRUCTURE, COMPOSITION, AND FUNCTIONS OF THE SKIN DERMA- SKIN SKIN/INTEGUMENT – the largest organ of the body, approximately 5 kg of the body weight thick in palms and soles, thin in eyelids and scrotum

3. Functions of Skin Protects from injuries Acts as barrier and regulates what enters/leaves body. Regulates body temperature. Synthesizes, stores vitamins. Sensory functions Excretion Absorption

4. Main layers of the Skin Epidermis – outermost skin layer 2.Dermis – true skin layer 3. Hypodermis – the subcutaneous layer

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

8. EPIDERMAL DIFFERENCES I.Epidermis of fishes and Aquatic amphibians GLANDS 1.MUCOUS GLANDS secretes gelatinous substance mucin in frogs; for water absorption and respiration in fish; defense mechanism for predations

9. 2.SEROUS GLANDS -secretes poisonous alkaloids for protection against predators. 3.PHOTOPHORES GLANDS -contains light-emittingn

10. II.EPIDERMIS OF TERRESRIAL OR LAND VERTERATES GLANDS 1.MAMMARY GLANDS secretes milk-feed the young both sexes;male-non functional;female-location 2.SWEAT GLANDS AND SUDORIFEROUS GLANDS produce sweat/perspiration cooling mechanism to regulate body temp

11. 3.OIL/ SEBACEOUS GLANDS secretes oilo/sebum;for lubrication/mare skin moist/shiny 4.UROPYGIAL GLAND [BIRDS] tail of uroryogium secretes oil,oiling the beark;shiny feathers/preening by beaks

12. 5.SEROUS GLANDS [SNAKE] secretes poison/toxic alkaloids 6.CERUMINOUS GLANDS [MAN] -secretes cerumen 7.GLANDS OF ZELS -moits the eyelashes 8.MELBOMIAN GLANDS -moists the eyelids

13. TYPES OF GLANDS ACCDG. TO MANNER OF SECRETION 1.MEROCRINE GLANDS [TRUE GLAND] release secretion thought memrbrane/cells remain intact. ex.unicellular integumentary glands sweat glands 2.HOLOCRINE GLANDS cells themselves constitute the secretion cells goes with secretion ex.sebaceous gland

14. APOCRINE SWEAT GLAND

15. 3.APOCRINE GLANDS intermediate in position secretions gathers at the tip or apical portion of the cell part of the cyptoplasm are pinched off with the secretion & then repair itself. ex.mammary glands

17. EPIDERMAL DERIVATIVES 1.MAMMALS HAIR- shaft,bulb,root NAILS-lunula,nail bed,root CLAWS-cats,monkeys,bird,etc, HOOVES-ungulates TUSKS-elephants,source of plastics

18. 2.BIRDS-BEAKS,PREENING,NESTING,F00D-FEATHERS-FOR INSULTION, FLIGHTS,BODY CONTOURS parts;shaft,barbs,barbules,,calamus Types; 1.flight feathers 2.covert feathers 3.pin feathers 4.filoplumers 5.hair feathers

20. 3.REPTILES epidermal scales-molting Exoskeleton turtles-scutes -corapace - plastron 4.AMPHIBIAN-rough/coarse skin 5.FISHES –with dermal scales Types of scales 1.CYCLOID SCALES-concentric ridges-milkfish 2.CTENOID SCALES-w/spines or ctenii 3.GANIOD SCALES-rhomboid shape, 4.COMOID SCALES-extinct fishes dermal armor 5.PLACOID SCALES-spines directed caudally-sharks,skates

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

37. Stratum Basale Lowest epidermal layer, near dermis Good nutrient supply Reproduces by mitosis Cuboidal, columnar in shape Moves to upper epidermis in 27 days.

39. Stratum Spinosum Living cells Dividing 8-10 cells thick Polygonal in appearance

41. Stratus Granulosum, Lucidum Poor nutrient supply. Flatten layer of cells. 3-5 cells thick. No cell division. Keratin accumulates. Found only in very thick skin. Translucent. Highly keratinized. Dead cells

42. Stratum Corneum 25-30 cells thick. Cells are filled with keratin and hardened. Sloughed off. Outer most layer of epidermis. Keratinocytes

43. Melanocyte Produces melanin for protection from UV radiation. Responsible for skin color. Melanoma.

44. Melanocyte

46. Irregular Dense Connective Tissue Collagenous fibers

47. Layers of the dermis Stratum papillarosum - superficial region(1/5) of the dermis,consists of areolar connective tissues with elastic fibers - contains dermal papillae that house capillaries,touch corpuscles,& free nerve endings 2. Stratum reticularosum - the deeper portion (4/5 of the dermis) - with dense regular conn. Tissue with bundles of collagen and elastic fibers - spaces between fibers contain adipocytes,hair follicles,nerves,sebaceous glands, sudoriferous glands

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

51. DERIVATIVES OF THE EPIDERMIS HAIR PARTS OF HAIR A. HAIR ROOT D. HAIR FOLLICLE B. HAIR SHAFT E. HAIR CORTEX C. HAIR BULB F. HAIR MEDULLA

53. Hair Follicle

55. TYPES OF HAIR A. ANGORA B. DEFINITIVE HAIR C. LANUGO 2. NAIL A. NAIL ROOT B. NAIL BED C. LUNULA

56. Angora Hair

57. Definitive Hair

58. Lanugo Hair

60. Sebaceous Gland DERIVATIVES OF THE DERMIS

61. Sweat Gland SKIN GLANDS

62. Types of Sweat Glands (Sudoriferous Glands) Merocrine glands: release fluid by exocytosis Eccrine Most common Secretion is mostly water with solutes Cools body down Apocrine Develops scent as bacteria metabolize secretion Stimulated when frightened, during pain, during emotional upset

63. APOCRINE SWEAT GLAND

64. ECCRINE SWEAT GLAND

66. Sensory Structures of Dermis Deep touch/pressure: Pacinian corpuscles Light touch/pressure: Meisner’s corpuscles Warm temperature: Free nerve endings Cold temperature: Free nerve endings Pain: Free nerve endings

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.

69. FACTORS INFLUENCING SKIN COLOR GENETIC INFORMATION AMOUNT OF MELANIN PIGMENTS DEGREE OF OXYGENATION HORMONES * MSH 5. EXPOSURE TO SUNLIGHT

70. WHITE SKIN

71. BROWN SKIN