Skin and Body Membranes I and IIMucous Membranes: Prone to DessicationSerous Membranes- Thin linings of organs and body wallConnective Tissue MembraneCutaneous MembraneFunctions of the Integumentary SystemSkin StructureEpidermisDetail of Epidermal Skin StructureDermisSlide 11Layers of the Dermis: Papillary LayerLayers of the Dermis: Reticular LayerNormal Skin Color DeterminantsAppendages of the SkinCutaneous Glands: Sebaceous & SweatAppendages of the Skin: HairSlide 18Appendages of the Skin: NailsAbnormal or Injured Skin ConditionsBurnsSlide 22Slide 23Slide 24Abnormal Conditions: Skin Cancer TypesABCD Rule in Detecting MelanomaSkin Tags (Acrochordons/ Cutaneous Papillomas)Skin Changes Over a LifetimeSkin and Body Membranes I and IITypes of Body MembranesCutaneous, mucus, serousThe Integumentary System (Skin)Skin Structure (epidermis, dermis)Skin Color (pigments and body conditions)Appendages of the Skin (oil & sweat, hair, nails)Diseases/Injuries to Skin (infections, burns, cancer)Changes in the Skin Over a LifetimeMucous Membranes: Prone to DessicationAlso: Urethra Vaginal tract Digestive tract, anus Nostrils Epithelium of the esophagusFound lining the inside edges of organs or tracts that empty into the exterior of the bodySerous Membranes- Thin linings of organs and body wall• Parietal serosae line internal body walls• Visceral serosae cover internal organsConnective Tissue MembraneSynovial membraneCutaneous MembraneFunctions of the Integumentary System1. Protection (chemical, physical, biological)2. Body temperature regulation ( perspiration, dermal vessels)3. Cutaneous sensations (temperature, touch, and pain)4. Metabolic functions (synthesis of vitamin D precursor and collagenase; chemical conversion of carcinogens and some hormones5. Blood reservoir—up to 5% of body’s blood volume6. Excretion—nitrogenous wastes and salt in sweatSkin StructureEpidermisKeratinized stratified squamous epithelium Cells of epidermisKeratinocytes—produce fibrous protein keratinMelanocytes10–25% of cells in lower epidermisProduce brown pigment melaninEpidermal dendritic (Langerhans) cells—macrophages that help activate immune system Tactile (Merkel) cells—touch receptorsDetail of Epidermal Skin StructureMelanocyteMelanin granuleTactile (Merkel) cell Sensorynerve endingEpidermaldendritic cellDermisKeratinocytesStratum corneum20-30 layers of dead keratinized cells; glycolipids in interstitial spaces.Stratum granulosumThree to five layers of flattened cells,organelles deteriorating; cytoplasm full of released lipidsStratum spinosumSeveral layers of keratinocytes unified by desmosomes. Stratum basaleone row of actively mitotic stem cells; melanocytes and epidermaldendritic cells.DesmosomesMnemonic: Basically, the spinning by granny is loose and corny. Stratum lucidumVery thin layer of dead, translucent keratinocytes; only palms, soles of feetDermisStrong, flexible connective tissueCells include fibroblasts, macrophages, and occasionally mast cells and white blood cellsTwo layers: PapillaryReticularSkin StructureFigure 5.1EpidermisHair shaftDermisReticularlayerPapillarylayerHypodermis(superficial fascia)Dermal papillaePoreSubpapillaryvascular plexusAppendagesof skin • Eccrine sweat gland• Arrector pili muscle• Sebaceous (oil) gland• Hair follicle• Hair rootNervous structures• Sensory nerve fiber• Pacinian corpuscle• Hair follicle receptor (root hair plexus)Cutaneous vascularplexusAdipose tissueLayers of the Dermis: Papillary LayerPapillary layerAreolar connective tissue with collagen and elastic fibers and blood vesselsDermal papillae contain: Capillary loops Meissner’s corpuscles (touch se0nsing)Free nerve endings .1Layers of the Dermis: Reticular LayerReticular layer~80% of the thickness of dermisCollagen fibers provide strength and resiliency Elastic fibers provide stretch-recoil propertiesPacinian corpuscles (pressure and vibration sensing)Normal Skin Color DeterminantsChemicals in the SkinMelaninCaroteneHemoglobinBody ConditionsErythmea (from embarrassment, fever, tension)Pallor/Blanching (stress, etc.)Jaundice from liver diseaseBruises from hematomasCyanosis from low blood oxygenAppendages of the SkinDerivatives of the epidermisSweat glandsOil glandsHairs and hair folliclesNailsCutaneous Glands: Sebaceous & SweatEccrine (Merocrine)Sweat Glandswatersaltsvitamin C metabolic wastes ammonia urea uric acid lactic acid Sebaceous glands(holocrine)Sebum- fragmented cells - fatty acids- Low pH (antibacterial) Apocrine sweat glands confined to axillary and genital areas- Sebum: sweat + fatty substances and proteins-Ducts connect to hair follicles-Functional from puberty onward (as sexual scent glands?)Specialized apocrine include- Ceruminous glands- Mammary glandsAppendages of the Skin: HairHair and Hair FolliclesAppendages of the Skin: HairHair follicleand arrectorpili muscleAppendages of the Skin: NailsFinger Nail and Nail Bed(Eponychium)Abnormal or Injured Skin ConditionsInfections and Allergies of the SkinAthletes foot (caused by tinea pedia fungus)Boils and carbuncles (caused by inflammation and/or bacterial infection of oil glands or folliclesCold sores (caused by viruses like Herpes)Contact dermatitis (caused by allergic reaction)Impetigo (caused by staph bacteria)Psoriasis (scaly skin caused by overproduction and of cells)BurnsHeat, electricity, radiation, certain chemicalsBurn (tissue damage, denatured protein, cell death)Immediate threat:Dehydration and electrolyte imbalance, leading to renal shutdown and circulatory shockAbnormal or Injured Skin ConditionsThe Rule of Nines for Estimating Burned Surface AreaBurns are critical if: • >25% has second-degree• >10% has third-degree• Any of face, hands, or feet with third-degreeAbnormal or Injured Skin ConditionsBurnsFirst-degree burnsOnly epidermis is damagedSkin is red and swollenSecond degree burnsEpidermis and upper dermis are damagedSkin is red with blistersThird-degree burnsDestroys entire skin layerBurn is gray-white or blackPartial thickness burnsFull thickness burnAbnormal or Injured Skin ConditionsCancers (Cause: UV, freq. irritation)Basal cell carcinomaLeast dangerousMost common typeArises from stratum basaleSquamous