integumentary system the skin (including sweat and oil glands), hair and nails

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INTEGUMENTARY SYSTEM The skin (including sweat and oil glands), hair and nails

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  • INTEGUMENTARY SYSTEMThe skin (including sweat and oil glands), hair and nails

  • Integumentary SystemIntegument = coveringIncludesSkin including sweat and oil glandsHairNails

  • Integumentary System FunctionsProtectionprotects underlying tissues and organsThree types of barriersChemical barrierskin secretions, melanin (protects from sun), acid mantle of skin decreases bacterial growth (sebum kills bacteria) Physical or mechanical barriercontinuous surface of skin (hard-fairly impermeable to disease)Biological barrierLangerhans cells and phagocytes (all work against disease)

  • Functions continuedExcretionexcrete salts, H2O, organic wastes through sweat3. Body temperature regulationIf air temp. is cold, then blood vessels in dermis constrict which reduces heat loss through skinIf body temp. is hot, then blood vessels in dermis dilate bringing blood to skin surface where it is cooled

  • 4. Touch reception- nerves in the dermis give us lots of info about our environment- touch, pressure pain, hot and cold5. Vitamin D production- when skin is exposed to UV radiation it makes vitamin D

  • RegionsEpidermisSurfacemany layers of epithelial cellsFunctionprotectionDermisUnder epidermisthicker layermost of skin is dermisConnective tissue with blood vesselsSubcutaneous layer (hypodermis or superficial fascia)Loose (fatty) connective tissueConnects skin to underlying organs

  • EpidermisSurface of skinStratified squamous epithelium4 cell types:1. Keratinocytesmost common, make keratin(protein that makes skin strong, flexible and water resistantKeratin is the basic component of hair, calluses and nailsWhen keratinocytes reach the skin surface, theyre dead cells which get worn offTotally new epidermis every 35-45 days!

  • Epidermis4 types of cells (cont.)2. Merkels cells- touch reception3. Melanocytes- produce the pigment melanin4. Langerhans cells- part of bodys defense against disease

  • Strata of the EpidermisStratum (singular) = layer

    5 layers starting with the deepest1. Stratum germinativum (stratum basale)attached to basement membrane, cells are specialized for division. One cell layer thick.2. Stratum spinosum (spiny layer)several cell layers thick, spiny projections hold cells together3. Stratum granulosum (grainy layer)2 or 3 layers of flattened cells, keratin formation begins here

  • Strata of the Epidermis4. Stratum lucidum (clear layer)found in thick skin (palms and soles)cells flattened and densely packed5. Stratum corneum (cornu = horn)20-30 cell layers thick. Dead cells filled with keratin (organelles die as keratin fills cells). Lets skin surface be a protective overcoat for the body

  • DermisStrong, flexible, connective tissue region of the skin with lots of nerve fibers, blood vessels, lymphatic vessels

  • Dermis2 layers:1. Papillaryloose connective tissue with dermal papillae that push into the epidermis. Patterns created by dermal papillae create fingerprints and line patterns on feet.

  • Dermis2. Reticulardense irregular connective tissue can tolerate stress from many directions because fibers run in many directions.Lines of cleavage bundles of interlocking collagen fibers that form patterns: surgical lines are often made parallel to lines of cleavage so that skin gapes less, heals more quickly, has less obvious scarring

  • Dermis (continued)Flexure linesfolds in skin that allow joint movementStretch markstears in dermis caused by excessive skin stretching. Silvery scars = striae

  • Stratum GerminativumStratum corneumStratum lucidumStratum granulosumStratum spinosumSubcutaneous layerSweat glandDermisAdipose tissuePacinian corpusclePoreMeisners corpuscleHair shaftDermal papillaeSebaceous glandArrector pili muscleHair follicleHair rootVeinArtery

  • Skin Color(3 Pigments)Melaninyellow to orange to brownmade by melanocytes and transferred into keratinocytes (keratin cells)Skin color varies by the amount and kind of melanin made NOT by number of melanocytes(everyone has the same number of melanocytes)Black and brown skinned people make more and darker melanin than lighter skinned peopleFreckles and dark moles show local accumulations of melanin

  • Skin Color (3 Pigments)Sun exposure leads to a build up of melanin providing some protection from the sunExcessive sun exposure damages skin (elastic fibers clump leading to leathery, wrinkled skin and damage to the immune system) and can change DNA in cells leading to skin cancerMelanin is a natural sunscreenSome antibiotics and antihistamines increase the skins sensitivity to the sun-> rashes, blisters and skin peeling

  • Skin Color (3 Pigments) continuedCaroteneyellow/orange pigmentFound in stratum corneum and subcutaneous adipose tissueShows most in palms and solesFound in fruits and vegetablesAsian skin color is the result of a combination of carotene and melaninCarotene and keratin sound alike- whats the difference?

  • 3. Hemoglobinred pigment from well oxygenated bloodShows in pinkish color of caucasians (transparent epidermis) so hemoglobin from the capillaries in the dermis shows throughToo little oxygen causes skin to look blue (cyanosis). Can be seen in mucous membranes and nail beds of dark skinned people.This can be caused by heart failure and severe respiratory disorders.

  • Skin Color ChangesChanges can be caused by emotional states and/or diseaseErythemaredness (embarrassment, fever)Pallorpaleness (fear, anemia)Jaundiceyellowing (liver disease)Bronzingmetallic appearance (Addisons disease)Bruisesblood escapes from vessels and clots in tissues (hematoma). May be result of too little vitamin C or a bleeding disorder.

  • Hair StructureShape of shaft determines whether hair is curly or straightFlat shaft=curlyOval shaft=wavyRound shaft= straight

    3 layers of hair MedullaCortexCuticle

  • Accessory StructuresHair and hair folliclesFunctions of hair:Protects head-from sun, heat loss, and physical traumaShields eyes (lashes)Helps keep dust and particles out of respiratory tract (nose hairs)

  • Hair StructureProduced and contained in hair follicleMade of keratinShaftpart of hair above skin surfaceRootpart of hair beneath skin surface

  • Hair ColorMelanocytes at base of hair send melanin into cells of cortexcombinations of yellow, brown & black melanin produce all hair colorsWhite or gray hair caused by decreased melanin production causing air bubbles to replace melanin in the hair shaft.

  • CuticleCortexMedullaMelanocyteBulb

  • Hair GrowthGrowing part of hair is at the root (in the bulb)Hair follicles begin deep in the dermis, sometimes even in the subcutaneous layerOther structures connected with hair:Nerve endings around bulbSebaceous (oil) glands lubricate hairArrector pili muscles--smooth muscle in dermisPull on hair follicle to make it stand upgoose bumpsActivated by cold, fright, or other strong emotion

  • Hair Growth (continued)100,000 hairs in scalp, 30,000 in beardWhere on your body do you have no hairs?3 typesVellusfine body hair of women and kidsTerminalcoarser, longer hair of scalp, eyebrows, pubic and axillary areas as well as face and chest of menIntermediateall hair that doesnt fit into other categories

  • Hair Growth (continued)Nutrition and hormones affect hair growthPoor nutrition (esp. low protein) iIncreased blood flow hTestosterone hOther factors that reduce hair growth: high fever, surgery, emotional trauma, drugsHirsutism

  • Hair GrowthHirsutism- excessive hair growth especially male pattern hair growth in women (often caused by adrenal gland tumor)

  • Hair Growth (continued)Growth averages 1.5-2.2 mm per weekGrowth is fastest from teens age 40Hair thins with age because hairs are not replaced as fast as theyre lostGrowth cycleactive phase followed by resting (inactive or dormant) phase Scalp follicles active for years, then inactive for a few months (shed 50-90 a day)Eyebrow follicles active for 3-4 monthsAlopecia = baldness

  • Hair GrowthAlopecia=baldnessUsually starts at anterior hairline and progresses posteriorlyTerminal hairs are replaced by vellus hairsMale patterned baldness- hereditary, sex-linked. Growth cycles become super shortMedicine or hair transplant

  • Accessory StructuresNailsSimilar in structure to hoof or claw in animalsHave free edge (visible) and root (beneath skin)Pink because of blood supply in dermisStructure:Lunulawhite crescent at baseCuticlethickened fold of skin at baseNail bedstratum germinativum under entire nail

  • Accessory StructuresSudoriferous GlandsSudoriferous Glands = Sweat Glands (2 types)3 million over body EXCEPT: lips, nipples and parts of external genitalia1. Eccrine (merocrine) sweat glandsMost abundant type especially on palms, soles and foreheadDucts go to pores on skin surfaceSecretion = sweat99% water with salts and wastes.Function: maintain body temp.

  • Sudoriferous Glands (continued)2. Apocrine sweat glandsFound mostly in axillae and genital-rectal areasDucts end in hair folliclesApocrine sweat has same elements as eccrine sweat plus fatty acids and proteins.Bacterial action on fatty acids and proteins is what creates odorBegin to function at puberty.Ceruminous glandsspecialized apocrine glands that produce cerumin (ear wax)in the ear canal

  • Accessory StructuresSebaceous GlandsSebaceous Glands = Oil GlandsFound all over body except palms and solesLarger on face, neck and upper chestSebum = oily secretionusually travels through duct to hair follicle, sometimes to pore on skin surfaceFunctionssebumSoftens and lubricates hair and skinPrevents water loss from skinKills bacteria

  • Sebaceous Glands (continued)Sex hormones cause sebaceous glands to become active at pubertyClinical terms:Whiteheadblocked sebaceous glandBlackheadsebum dries and darkensAcneinflammation of sebaceous gland usually due to bacterial infectionSeborrheaover activity of sebaceous glands. Causes oily scales that come off.

  • Skin DisordersAlbinism(albino) melanocytes cant make melaninAbsence of pigmentation in skin, hair, eyes.Athletes footfungus infection leads to itchy, red, peeling skin between toesBoilsinflammation of hair follicles and sebaceous glands (cause: bacterial infection)Cold soresherpes virus infection. Causes blisters filled with fluid around lips and mouthContact dermatitiscaused by exposure to chemicals that create allergic response

  • Albino & Athletes Foot

  • Boils & Cold Sores

  • Contact Dermatitis & Decubitus Ulcer

  • Skin Disorders (continued)Decubitus ulcersbed sores/pressure soresImpetigocontagious rash Mongolian spotsbruised looking area at sacrumbirth markPsoriasischronic, hereditary condition. Reddened spot covered with scales.Vitiligoloss of pigment in patches of skinGenital Wartscaused by HPV

  • BurnsTissue damage caused by heat, electricity, chemicals, radiationBurns are a major cause of death for those
  • BurnsImmediate threat to lifefluid lossFluids contain proteins and electrolytes, fluid loss->dehydration and electrolyte imbalance->kidney failure and decreased blood circulationLost Fluids need to be replaced immediatelyNutrient needs are very high in burn patients.

  • BurnsAfter immediate crisisinfection is biggest threat to lifeBarrier destroyedImmune system function decreases

  • BurnsOnly epidermis is damagedredness, swelling, pain. Heal in 2-3 daysEpidermis and upper part of dermis1st degree S&S plus blisters. Skin regeneration. Heal 3-4 weeks if no infection.Full thicknessburned areas look gray-white or black. Nerve endings destroyed(no pain). Skin grafting needed

  • Rule of NinesMethod for estimating how much of skin surface is burned.Body is divided into areas that amount to 9% of skin surface.

  • Critical Burns3 classes of critical burns30% of body has 2nd degree burnsMore than 10% has 3rd degree burnsAny 3rd degree burn on face, hands or feet

  • Skin Cancer3 types:1. Basal Cell CarcinomaStarts in stratum germinativumMost common, least malignantFull cure with surgical removal in 99%Found on surfaces exposed to the sunStart as shiny, raised area and develop into central ulcer surrounded by pearly edge

  • Skin Cancer Types (continued)2. Squamous cell carcinomaStarts in stratum spinosumScaly reddened bumpgrows rapidlySun exposureMetastasis rare

  • Skin Cancer Types (continued)3. Malignant MelanomaCancer of melanocytesRarer than other types, but deadlyMelanomas often have irregular borders, multiple colors, rapid growth, and bleed easily.

  • ABCD Rule for MelanomaBe on the look out and notify your doctor about any of the following changes to a mole or birthmark:

    A is for ASYMMETRY: One half of a mole or birthmark does not match the other. B is for BORDER: The edges are irregular, ragged, notched, or blurred. C is for COLOR: The color is not the same all over, but may have different shades of brown or black, sometimes with patches of red, white, or blue. D is for DIAMETER: The area is larger than 6 millimeters (about inch -- the size of a pencil eraser) or is growing larger.

    The most important warning sign for skin cancer is a spot on the skin that changes in size, shape, or color.

  • DevelopmentEmbryonic developmentBy 4th monthskin well formed5th and 6th monthlanugo7th month vellus hairs appearAt birthvernix caseosa (produced by sebaceous glandsNewborn skin thin and often covered by milia (sebaceous secretion) on nose and cheeksgoes away by 3-4 weeks after birth

  • Development (continued)AdolescenceSkin and hair oilerAcne usually goes away in early adulthoodSkin usually looks its best in 20s and 30s

  • DevelopmentOld AgeChanges caused by continued exposure over timeEpidermal cells have slower mitosisskin thinsSebaceous and sweat glands less activeskin gets drier and itchyCollagen and elastic fibers fewer and stifferSubcutaneous fat layer decreases leading to decreased tolerance to coldMelanocytes less activedecreased protection from sunLight skinned, light haired people tend to show signs of age soonerTo reduce aging changesdecrease sun exposure, eat well, get lots of fluids

  • Integumentary System Effect on other SystemsEntire skin is only as thick as a paper towel!When the skin is damaged almost every body system reactsEach system gets something from the integumentary system and gives something to the integumentary system.What examples can you think of?