integumentary system. (hypodermis) integumentary system skin hair nails associated structures...

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  • Integumentary System

  • (Hypodermis)

  • Integumentary SystemSkinHairNailsAssociated Structures (vessels, nerves, glands)

  • MembranesEpithelial membranesCutaneousMucousSerous Parietal vs visceralPleura, pericardium, peritoneum

  • Integumentary SystemSkin (cutaneous membrane)Main layers superficial to deepEpidermisDermisHypodermis -not always considered part of skin(Hypodermis)

  • Functions of SkinProtectionSensationMovement without energyExcretionVitamin D production needed to absorb calciumSun+SkinVit D blood kidney/liver calcitriol blood regulates calcium & phosphorousImmunityHealing WoundsBody temperature homeostasisvasoconstriction & vasodilation

  • Skin Structure

  • EpidermisEpidermis outer layerKeratinized stratified squamous epitheliumAvascular (hardened by keratin)Renews itself ~ every 45 days

  • Epidermis cell typesKeratinocytesproduce keratin waterproofing proteinOriginate in deeper layers & get pushed to surface becomes keratin filled & diesConnected to each other by desmosomes & tight junctionsCell production & keratinization are accelerated in areas of frictionCallus thickened skin

  • Epidermis cell typesMelanocytesProduce melanin Prevents DNA mutation from the UV radiationUV increases melanin productionSame number in everyone, but different amount of pigment producedAccumulation of melanin results in freckles and moles

  • Epidermis Skin ColorDetermined by three factors:Types of pigments presentMelanin brown, black, or yellow pigmentCarotene


    Blood circulationStratum corneum thicknessOrange-yellow pigment from some vegetablesVitamin A precurser vitamin A forms retinal which is needed for sightAccumulates in adipose and stratum corneum cellsRed, oxygen-carrying pigment in erythrocytesMore obviously detected in fair skin

  • Skin as a DiagnosticSkin color is influenced by emotional & disease states: You should know the states that cause these.Cyanosis bluish color - lack of oxygenErythema redness heat, inflammation, feverAlbinism genetically black, but white no melanin produced from melanocytesPallor paleness lack of blood flowJaundice yellowish color liver damage; accumulation of bilirubinBronzing bronze (tan) Addisons diseaseHematomas black & blue blood under skin

  • 5 strata of the Epidermis Deep to SuperficialStratum basalehighly mitotic (produces new skin layer)~ 25% melanocytesStratum spinosumSlightly mitoticContains Langerhans macrophagesSeveral layers of many sided cells (looks spiny)

    Stratum granulosumAlso contains Langerhans cellcontains keratohyalin (helps form keratin)Stratum lucidumONLY found in thicker epidermis palms, soles, callusCompletely keratinized (and dead!)contains closely packed, clear cells that contain gel-like substance eleiden

  • 5 strata of the EpidermisStratum corneumOutermost layerAlso completely keratinizedDead cellsTough, waterproofing protection

  • DermisMiddle layer of skinContains hair folllicles, glands, nerves, vessels, muscleAll four tissue types presentMainly strong, flexible CT - Two layers

  • DermisPapillary layerContains Areolar CTDermal papillaeIndent into epidermisforms fingerprintsImportant for gripContains blood vesselsMeissners Corpuscles nerve (touch) receptors

  • DermisReticular layerDense irregular CT contains blood vessels, nerves, glands, adiposePacinian Corpuscles nerve endings responsible for sensitivity to deep pressure touch and high frequency vibrationCollagen prevents overstretching and tearing of skinElastin allows skin to stretchstretch marks dermal tears

  • Hypodermis

    Not usually considered part of the skinAlso called subcutaneous layerSite of subcutaneous injections absorbed directly into blood streamAnchors skin to underlying organs, shock absorption, insulationComposed mostly of adipose tissueVery vascular

  • Skin Appendages

  • Appendages of the SkinHairMinor protective functions (retain heat, decrease sunburn, eyelashes protect eyes)Structureshaft projects from skinfollicle extends into dermis root lies within the folliclebulb contains CT, vessels and nervessebaceous gland lubricates hairarrector pili muscle attached to follicle and contracts to move hair (hair growth, goosebumps)

  • Hair

  • Appendages of the SkinHair Growthinfluenced by: (in this order)nutrition - main influencehormones blood flowbaldness ( alopecia )male pattern baldness - sex linked recessive genetic traitthinning can be caused by medications, nutrition, stress, etc.Hair Pigmentcaused by proportions of 3 melanin typesdark hair true melaninblonde and red melanin with iron and sulfurgray/white hair - melanin replaced by air bubbles in shaft

  • Appendages of the SkinNailsScale-like modifications of the epidermisHeavily keratinizedStratum basale extends beneath the nail bed to form nail matrixResponsible for growth ( matrix region)Lack of pigment makes them colorlessLunula little moon area of cell growth (white semicircle at base of nail)Cuticle area of skin that covers base of nail

  • Nail Structures

  • Sweat GlandsEccrine glandsWidely distributed in skin: abundant on palms, soles, foreheadSweat composition: mostly water with a slightly acidic 4-6 pHFunction: thermoregulation

    Apocrine glandsDucts empty into hair follicles Found mainly in anogenital & axillary regionBegin to function at puberty due to hormones / pheromonesOrganic contents: Fatty acids and proteins can have a yellowish color that stains clothesOdor is from associated bacteria

    Ceruminous glandsModified apocrine gland Found in outer 1/3 of ear canalProduce ear wax to trap invaders

  • Appendages of the SkinSebaceous glands all over except palms and soles of feetProduce oil for waterproofingLubricant for skin & kills bacteriaMost with ducts that empty into hair folliclesGlands are activated at puberty: stimulated by hormones Acne active infection of sebaceous glands

  • Burns

  • BurnsProtein denaturation and cell death caused by heat, electricity, UV radiation, or chemicals2 main dangersDehydrationLoss of fluids & Electrolytes lead to:Renal ShutdownCirculatory shockInfectionSkin (mechanical) barrier lostImmune system depresses

  • Rules of NinesWay to determine the extent of burnsPrimary importance is to estimate fluids needed for rehydrationBody is divided into 11 areas for quick estimationEach area represents about 9%

  • Rule of nines diagram

  • Partial Thickness BurnsSlide 4.27First-degree burnsOnly epidermis is damagedLocal redness, swelling, & painUsually heal in 2-3 days (short time period) with NO scarring

  • Partial Thickness BurnsSecond degree burnsEpidermis and dermis & structures within dermis are damagedAppearance of blisters of any sizeSkin regeneration in 3-4 weeks with some scarringThere is a danger of infection

  • Full Thickness BurnsThird-degree burnsEpidermis, Dermis, Hypodermis and all structures within are completely destroyedUsually painless at site of burn due to destruction of sense receptorsBurn is gray-white, tan, brown, black, or deep cherry redSurrounded by areas of 1st & 2nd degree burns that will be painfulTreatments are numerous but will involve skin grafting of some sort, fluid replacement and debridement

  • All degrees of burns

  • Skin CancerSkin cancer is the most common type of cancer2 out of 5 cancers are skin cancers

  • Skin CancerCancer uncontrolled cell growthCaused by damage to the DNA usually through chemicals or radiationTwo typesBenignDoes not spread (encapsulated)MalignantMetastasized (moves) to other parts of the body

  • Skin Cancer TypesBasal cell carcinomaLeast malignant Most common type (90% of skin cancers)Arises from stratum basalecannot produce keratinBoundary lost between dermis and epidermisSeldom metastasizes treated surgically or by radiation 99% cure rate if caught earlySignsPale marksReddish patchesRound, smooth growth with raised edgeShiny bumpsSores that dont heal

  • Basal Cell Carcinoma

  • Basal Cell Carcinoma

  • Skin Cancer TypesSquamous cell carcinoma2nd most common skin cancerHighest risk fair skin, light hair, blue/green eyesArises from stratum spinosumMetastasizes to lymph nodes if left untreated1500-2000 deaths in US per yearEarly removal allows a good chance of cureSigns are same as basal cell carcinoma

  • Squamous Cell Carcinoma

  • Cumulative EffectsIMPORTANT TO KNOWBasal cell & squamous cell carcinomas are due to cumulative effects of the suns radiation (or chemical exposures as well)These tend to develop in ages 30-40s after years of daily sun exposure

  • Skin Cancer TypesMalignant melanomaLeast common most deadly of skin cancersOriginates melanocytesMetastasizes rapidly to lymph and blood vesselsEarly detection is critical see notes for survival rates

  • Intensive EffectsMalignant Melanoma tends to occur in younger ages (as well as older people)It is due to brief intense exposures (aka: sunburns)This is the most serious form of skin cancer and MUST be caught early to be treated successfully!

  • ABCD RuleA = AsymmetryTwo sides of pigmented mole do not matchB = Border irregularityBorders of mole are not smoothC = ColorDifferent colors in pigmented areaD = DiameterSpot is larger then 6 mm in diameter (pencil eraser)Mole starts growing/changing in size

  • Malignant Melanoma

  • Melanomas

  • Melanomas

  • PreventionWear sunscreen whenever outside or cover upavoid midday sun between 10-2 and beware of reflected lighthigher altitudes - every 1000 ft above sea level, radiation increases 4-5 %Be cautious about tanning bedsMedications - tetracycline (antibiotics), Retin A, birth control, antidepressants, diuretics, and anti-inflammatories cause photosensitivityavoid sunburnsexamine skin regularly - remember ABCD rule have full body check by dermatologist once a year

  • Other Integumentary System disorders

  • Contact dermatitis (Ezcema)Exposure to allergen/irritant (ie. poison ivy) cause allergic reaction inflammation, red, itchy skinnot contagiousover the counter meds; sometimes RxPrevention by avoiding allergen/irritantBlistersEpidermal cell injury or separation of epidermis from dermisWartsBenign neoplasms, but can turn malignantContagiousRemove by freezing, drying, laser therapy, chemicalsBoilsBacterial infection that infects hair folliclesLarge, inflamed, pus-filled lesions

  • TineaFungal infections (ringworm, jock itch, athletes foot)Reddish discoloration, scaling, crustingTreat with antifungal agentPrevent recurrence by keeping skin dry

    ImpetigoCaused by bacterial infectionMostly childrenReddish discoloration turns into blisters and yellowish crustsIf turns systemic, it is life threatening

  • PsoriasisCause is unknown, probably geneticTriggered by trauma, infection, stressCutaneous inflammation, scaly lesions Due to excessive rate of epithelial cell growth

    UrticariaHivesRaised, red lesions caused by blood vessel leakageSevere itchingCauses (hypersensitivity, allergic reactions, physical irritants, systemic disease)

    SclerodermaAutoimmuneAffects blood vessels and CTHard skin lesionsMore common in women

    Decubitus ulcersbedsores / pressure soresLack of blood flow causes tissue damage

  • Acne * Clogged sebaceous follicles from abnormal shedding of skin cells * Bacteria build-up in sebaceous glands * Enhanced by hormones * Over the counter meds; sometimes Rx * Prevention-avoid using oils, greasy moisturizers, facewash, and makeup-wash hands before applying makeup-use non-scented ordinary mild soap-keep hands away from face