The-Integumentary-System医疗培训课件

1、General AnatomyA large organ composed of all 4 tissue types22 square feet 1-2 mm thickWeight 10 lbs.1General AnatomyA large organ cOverview3 Major layers of skinEpidermis is epithelial tissue onlyDermis is layer of connective tissue, nerve & muscleHypodermis (subcutaneous) is layer of adipose & areo

2、lar tissues2Overview3 Major layers of skinOverview of EpidermisStratified squamous epitheliumContains no blood vessels4 types of cells5 distinct strata (layers) of cells3Overview of EpidermisStratifieCell types of the Epidermis Keratinocytes-90%produce keratin Melanocytes-8 %produces melanin pigment

3、melanin transferred to other cells with long cell processesLangerhan cellsfrom bone marrowprovide immunityMerkel cellsin deepest layerform touch receptor with sensory neuron4Cell types of the Epidermis KeLayers (Strata) of the EpidermisStratum corneumStratum lucidumStratum granulosumStratum spinosum

4、Stratum basale5Layers (Strata) of the EpidermStratum BasaleDeepest single layer of cells Combination of merkel cells, melanocytes, keratinocytes & stem cells that divide repeatedlyCells attached to each other & to basement membrane by desmosomes & hemidesmosomes6Stratum BasaleDeepest single lStratum

5、 Spinosum8 to 10 cell layers held together by desmosomesDuring slide preparation, cells shrink and look spinyMelanin taken in by phagocytosis from nearby melanocytes7Stratum Spinosum8 to 10 cell lStratum Granulosum3 - 5 layers of flat dying cellsShow nuclear degenerationContain dark-staining keratoh

6、yalin granulesContain lamellar granules that release lipid that repels water8Stratum Granulosum3 - 5 layersStratum Lucidum Seen in thick skin on palms & soles of feetThree to five layers of clear, flat, dead cellsContains precursor of keratin9Stratum Lucidum Seen in thick Stratum Corneum25 to 30 lay

7、ers of flat dead cells filled with keratin and surrounded by lipidsContinuously shedBarrier to light, heat, water, chemicals & bacteriaFriction stimulates callus formation10Stratum Corneum25 to 30 layersKeratinization & Epidermal GrowthStem cells divide to produce keratinocytesAs keratinocytes are p

8、ushed up towards the surface, they fill with keratin4 week journey unless outer layers removed in abrasionHormone EGF (epidermal growth factor) can speed up processPsoriasis = chronic skin disordercells shed in 7 to 10 days as flaky silvery scalesabnormal keratin produced11Keratinization & Epidermal

9、 GroSkin GraftsNew skin can not regenerate if stratum basale and its stem cells are destroyedSkin graft is covering of wound with piece of healthy skinautograft from selfisograft from twinautologous skintransplantation of patients skin grown in culture12Skin GraftsNew skin can not reDermisConnective

10、 tissue layer composed of collagen & elastic fibers, fibroblasts, macrophages & fat cellsContains hair follicles, glands, nerves & blood vesselsMajor regions of dermispapillary regionreticular region13DermisConnective tissue layer Papillary RegionTop 20% of dermisComposed of loose CT & elastic fiber

11、s Finger like projections called dermal papillaeFunctionsanchors epidermis to dermiscontains capillaries that feed epidermiscontains Meissners corpuscles (touch) & free nerve endings (pain and temperature)14Papillary RegionTop 20% of der Reticular RegionDense irregular connective tissueContains inte

12、rlacing collagen and elastic fibersPacked with oil glands, sweat gland ducts, fat & hair folliclesProvides strength, extensibility & elasticity to skinstretch marks are dermal tears from extreme stretchingEpidermal ridges form in fetus as epidermis conforms to dermal papillaefingerprints are left by

13、 sweat glands open on ridgesincrease grip of hand15 Reticular RegionDense irregulSkin Color Pigments (1)Melanin produced in epidermis by melanocytessame number of melanocytes in everyone, but differing amounts of pigment producedresults vary from yellow to tan to black colormelanocytes convert tyros

14、ine to melaninUV in sunlight increases melanin productionClinical observationsfreckles or liver spots = melanocytes in a patchalbinism = inherited lack of tyrosinase; no pigmentvitiligo = autoimmune loss of melanocytes in areas of the skin produces white patches16Skin Color Pigments (1)MelaninSkin C

15、olor Pigments (2) Carotene in dermisyellow-orange pigment (precursor of vitamin A)found in stratum corneum & dermis Hemoglobinred, oxygen-carrying pigment in blood cellsif other pigments are not present, epidermis is translucent so pinkness will be evident17Skin Color Pigments (2) CaroteAccessory St

16、ructures of Skin Epidermal derivativesCells sink inward during development to form:hairoil glandssweat glandsnails18Accessory Structures of Skin E Structure of Hair Shaft - visiblemedulla, cortex & cuticle Root - below the surfaceFollicle surrounds root19 Structure of Hair Shaft - viHair Related Str

17、uctures Arrector pilismooth muscle in dermis contracts with cold or fear.forms goosebumps as hair is pulled verticallyHair root plexusdetect hair movement20Hair Related Structures ArrectHair ColorResult of melanin produced in melanocytes in hair bulbDark hair contains true melaninBlond and red hair

18、contain melanin with iron and sulfur addedGraying hair is result of decline in melanin productionWhite hair has air bubbles in the medullary shaft21Hair ColorResult of melanin pr Functions of HairPrevents heat lossDecreases sunburnEyelashes help protect eyesTouch receptors (hair root plexus) senses

19、light touch22 Functions of HairPrevents heaGlands of the SkinSpecialized exocrine glands found in dermisSebaceous (oil) glandsSudiferous (sweat) glandsCeruminous (wax) glandsMammary (milk) glands23Glands of the SkinSpecialized Sebaceous (oil) glandsSecretory portion in the dermisMost open onto hair

20、shafts Sebumcombination of cholesterol, proteins, fats & saltskeeps hair and skin from soft & pliableinhibits growth of bacteria & fungi(ringworm)Acnebacterial inflammation of glandssecretions stimulated by hormones at puberty24Sebaceous (oil) glandsSecretor Sudoriferous (sweat) glands Eccrine (swea

21、t) glandsmost areas of skinsecretory portion in dermis with duct to surfaceregulate body temperature with perspiration Apocrine (sweat) glandsarmpit and pubic regionsecretory portion in dermis with duct that opens onto hair folliclesecretions more viscous function after puberty, “cold sweat”25 Sudor

22、iferous (sweat) glands E Ceruminous glandsModified sweat glands produce waxy secretion in ear canalCerumin contains secretions of oil and wax glandsHelps form barrier for entrance of foreign bodiesImpacted cerumen may reduce hearing26 Ceruminous glandsModified sweStructure of NailsTightly packed ker

23、atinized cellsNail bodyvisible portion pink due to underlying capillariesfree edge appears whiteNail rootburied under skin layerslunula is white due to thickened stratum basaleEponychium (cuticle)stratum corneum layer27Structure of NailsTightly packNail GrowthNail matrix below nail root produces gro

24、wthCells transformed into tightly packed keratinized cells1 mm per week28Nail GrowthNail matrix below nTypes of SkinThin skincovers most of bodythin epidermis (.1 to .15 mm.) that lacks stratum lucidumlacks epidermal ridges, has fewer sweat glands and sensory receptorsThick skinonly on palms and sol

25、esthick epidermis (.6 to 4.5 mm.) with distinct stratum lucidum & thick stratum corneumlacks hair follicles and sebaceous glands29Types of SkinThin skin29General Functions of the SkinRegulation of body temperatureProtection as physical barrierSensory receptors Excretion and absorptionSynthesis of vitamin30General Functions of the SkinRSkin Cancer1 million cases diagnosed per year3 co