Y khoa, dược - The integumentary system

20The Integumentary System20-2Learning Outcomes 20.1 List the functions of skin.20.2 Explain the role of skin in regulating body temperature.20.3 Describe the layers of skin and the characteristics of each layer.20.4 Explain the factors that affect skin color.20.5 Identify and describe common skin lesions. 20-3Learning Outcomes (cont.)20.6 List the accessory organs of skin and describe their structures and functions.20.7 Explain the process of skin healing, including scar production.20.8 Describe the effects of aging on skin. 20.9 List the different types of burns and describe their appearances and treatments. 20-4Learning Outcomes (cont.)20.10 Describe the causes, signs and symptoms, and treatments of various types of skin cancer.20.11 Describe the causes, signs and symptoms, and treatments of common skin disorders.20.12 Explain the ABCDE rule and its use in evaluating melanoma.20.13 Using the acronym CAUTION, list the seven warning signs of cancer. 20-5Introduction Integumentary system consists of skin and its accessory organsAccessory organs:Hair folliclesNailsSkin glandsSkin is the body’s outer covering and its largest organ.20-6Functions of the Integumentary SystemProtectionFirst line of defense againstBacteria VirusesProtects underlying structures fromUltraviolet (UV) radiation Dehydration20-7Functions of the Integumentary System (cont.)Body temperature regulationIf too hotDermal blood vessels dilateVessels carry more blood to surface so heat can escapeIf too coldDermal blood vessels constrictPrevents heat from escaping20-8Functions of the Integumentary System (cont.)Vitamin D productionNeeded for calcium absorptionSensationSensory receptorsExcretionSmall amounts of waste products are lost through perspiration20-9Apply Your KnowledgeWhat are the functions of the integumentary system?ANSWER: The functions of the integumentary system are protection, regulation of body temperature, vitamin D production, sensation, and excretion.Super!20-10Structure of SkinEpidermisDermisHypodermis or subcutaneous layerBack20-11EpidermisMost superficial layerTwo partsStratum corneum Outermost layerMostly dead cells form an impermeable layerStratum basale (stratum germinativum)Deepest layerCells constantly dividing and pushing older cells outwardTo Figure of Skin20-12Epidermis (cont.)Keratinocyte – most commonMakes and accumulates keratin Durable protein that makes the epidermis waterproof and resistant to pathogensMelanocyteMakes the pigment melaninTraps UV radiation and prevents damage to underlying layers of the skin20-13DermisDeeper of the two skin layersContains all major tissue types, plusSudoriferous (sweat) glandsSebaceous (oil) glandsHair follicles and arrector pili musclesCollagen, elastin, and nerve fibersBlood vesselsBinds the epidermis to the subcutaneous tissueTo Figure of Skin20-14Subcutaneous LayerHypodermisComposed ofAdipose (fat) and loose connective tissueBlood vessels and nervesFunctionsStorage in adipose tissueCushions and insulates underlying structuresTo Figure of Skin20-15Apply Your KnowledgeWhere are melanocytes and keratinocytes, and what is their function?ANSWER: Both are located in the epidermis of the skin. Keratinocytes make and accumulate keratin, which is a durable protein that makes the epidermis waterproof and resistant to pathogens.Melanocytes make the pigment melanin, which traps UV radiation and prevents damage to underlying layers of the skin.Excellent!20-16Skin ColorDetermined by amount of melanin in the epidermis of skinThe more melanin, the darker the skin colorRange is from yellowish to brownish20-17Skin Color (cont.)Oxygenated bloodAmount of oxygen dissolved in the hemoglobin of the red blood cellsHemoglobin – a pigment in the RBCsIf blood is well-oxygenated, skin will be pinkIf oxygen level in blood is low, skin will be pale or have a bluish color (cyanosis)20-18Apply Your KnowledgeWhat affects skin color?ANSWER: The amount of melanin produced by the melanocytes and the oxygenation of the blood.Nice Job!20-19Skin LesionsAny variation in the skinAs simple as a freckleAs serious as a tumor20-20Skin Lesions (cont.)Lesion NameDescriptionBullaA large blister or cluster of blistersCicatrixA scar, usually inside a wound or tissueCrustDried blood or pus on the skinEcchymosisA black-and-blue mark or bruiseErosionA shallow area of skin worn away by friction or pressureExcoriationA scratch; may be covered with dried blood20-21Skin Lesions (cont.)Lesion NameDescriptionFissure A crack in the skin’s surfaceKeloidAn overgrowth of scar tissueMaculeA flat skin discoloration, such as a freckle or a flat moleNodule A large pimple or small nodePapuleAn elevated mass similar to but smaller than a nodulePetechiaePinpoint skin hemorrhages that result from bleeding disorders 20-22Skin Lesions (cont.)Lesion NameDescriptionPlaqueA small, flat, scaly area of skinPurpuraPurple-red bruises usually due to clotting abnormalitiesScaleThin plaques of epithelial tissue on skin’s surfacePustuleAn elevated (infected) lesion containing pusTumorA swelling of abnormal tissue growth 20-23Skin Lesions (cont.)Lesion NameDescriptionUlcerA wound that results from tissue lossVesicleA blisterWhealAnother term for hive20-24Apply Your KnowledgeMatch the following:___ Keloid A. A blister___ Vesicle B. A crack in the skin’s surface___ Crust C. An overgrowth of scar tissue___ Fissure D. A small, flat scaly area of skin___ Ulcer E. Dried blood or pus on the skin___ Plaque F. A wound that results from tissue lossAEBFDCANSWER:BRAVO!20-25Accessory Organs Hair folliclesTube-like depressions in the dermis of skinGenerate hairsAlopecia (baldness) occurs when follicles dieArrector pili muscles attached to follicles cause goose bumpsSebaceous glandsProduce sebum to keep hair softPrevent bacteria from growing on skinNails Protect the ends of fingers and toesHard keratinDiagram20-26Accessory Organs (cont.)Sudoriferous (sweat) glandsLocated in the dermis of skinTypesEccrine glandProduce watery type of sweatActivated by heatApocrine glandProduce thicker type of sweat with more proteinsConcentrated in armpit and groin areasActivated by nervousness or stressDiagram20-27Accessory OrgansHair follicleSebaceous glandSudoriferous glandReturn20-28Skin HealingInjury  inflammationRedness due to dilation of nearby blood vesselsSwelling because vessels leak fluid into spaces between cellsPain because excess fluid activates pain receptors20-29Skin Healing (cont.)Inflammation promotes healing Extra blood to areaExtra nutrients for skin repairDefensive cells Injury occursBlood clot formsScab replaces blood clot Clotted blood and other dried tissueCollagen fibers replace scabBind the edges of wound; major component of scars20-30Apply Your KnowledgeHow does inflammation promote healing of the skin?ANSWER: Inflammation promotes healing by bringing extra blood, nutrients for skin repair, and defensive cells to the area of injury. Correct20-31Skin and AgingSkin loses firmness due to Loss of elastin and collagen fibers in dermisLoss and shifting of underlying adipose tissuesSkin color changesDermis becomes thinner and more transparentPaler due to decrease in circulation20-32Skin and Aging (cont.)Melanocytes decrease Those remaining gather  “age” spotsHair grays and becomes thinnerDecreased tolerance to temperature changesSudoriferous glands decrease in numberDecreased perspiration, hard to adjust to high temperaturesLoss in adipose tissue and decreased circulationIncreased sensitivity to cold20-33Apply Your KnowledgeWhat happens to the skin in the elderly?ANSWER: As a person ages, the skin loses firmness, skin color changes, melanocytes decrease, and tolerance to temperature changes decreases due to a loss of adipose tissue and sweat glands.Very Good!20-34BurnsSecond leading cause of accidental death in the U.S.Rule of nines is used to determine extent (coverage) of burnExtent of body surface area11 body areasRule of Nines20-35Back20-36Burn SeveritySuperficial – first-degreeEpidermis onlyPain, redness, swellingPartial-thickness – second-degreeEpidermis and dermisPain, redness, swelling, blistersFull-thickness – third-degree All layers of skin and often underlying structuresSkin appears charredAlways requires medical attentionBurns20-37 1st Degree 2nd Degree 3rd DegreeBack20-38Burns: TreatmentDo not remove anything sticking to the burnDo not apply butter, lotions, or ointmentsCool with large amounts of waterCover with sterile sheet or plastic bag20-39Apply Your KnowledgeUsing Figure 24-5, determine burn extent for a patient who has burnt his anterior face and both arms.Click for Figure 24-5 Rule of NinesANSWER: Head = 9%Both arms, hands, and shoulders = 18% + 18%9% + 18% + 18% = 45%It all adds up to a right answer!20-40Skin CancerBasal cell carcinoma – progresses slowly and rarely spreads to other body partsSquamous cell carcinoma – more likely to spread to surrounding tissuesMalignant melanoma – more aggressive and occurs anywhere Most arise from melanocytes20-41Basal Cell CarcinomaSigns and symptomsNew growth or sore that will not healWaxy, smooth, red, pale, flat, or lumpyMay or may not bleedTreatment: Curettage and electrodessication  CryosurgeryMohs’ surgery  Laser therapy20-4220-42Squamous Cell CarcinomaLess common than basal cell carcinomaFound on face, lips, ears, and backs of handsSigns and symptoms and treatments are the same as for basal cell carcinoma 20-43Malignant MelanomaSigns and SymptomsFrom melanocytesAppear on trunk, head, neck of menAppear on arms and legs of womenItches or bleedsTreatmentSurgery and biopsyRemoval of lymph nodesChemotherapy and radiation therapyImmunotherapy20-44Stages of MelanomaStage 0Only found in epidermisStage ISpread to epidermis and dermis (1 to 2 mm thick)Stage II2 to 4 mm thick plus ulcerationStage IIISpread to one or more lymph nodesStage IVSpread to other body organs or lymph nodes far from original melanoma20-45ABCDE RuleAAsymmetry – a mole should not become asymmetrical. It should look equal in size from side to side.BBorder – a mole should not have irregular borders and edges should not blur into normal tissue.CColor – a mole should not change or become mixture of colors. It should have even coloring.DDiameter – a mole should not grow larger than the diameter of a pencil eraser (6 mm.)EEvolving – a mole that has been changing in size, color and appearance, or growing in an area of previously normal skin20-4624-46Cancer Warning SignsC – Change in bowel or bladder habitsA – A sore that will not healU – Unusual bleeding or discharge T – Thickening or lumpI – Indigestion or difficulty swallowingO – Obvious change in wart or moleN – Nagging cough or hoarseness20-47Apply Your KnowledgeTrue or False:___ Basal cell carcinoma is the most aggressive form of skin  cancer and can form anywhere.___ Squamous cell carcinoma is more likely to spread to  surrounding tissues.___ Lesions of melanoma appear on trunk, head, neck of  men and on arms and legs of women.___ The borders of skin cancers are usually regular.___ Basal cell carcinoma progresses slowly and rarely  spreads to other body parts.ANSWER:FTTFTGood Job!Melanomas are more aggressive.Borders are irregular.20-48Common Skin DisordersAlopecia Results in hair lossCellulitisInflammation of connective tissue in skinDermatitis Inflammation of skin or a rashEczema Chronic dermatitisFolliculitis Inflammation of hair follicles20-49Common Skin Disorders (cont.)Herpes simplex Type 1 – cold soresType 2 – genitalHerpes zosterShinglesImpetigo Oozing skin lesions that eventually crust overPediculosisHead liceBody licePubic licePsoriasis Inherited autoimmune disorder20-50Common Skin Disorders (cont.)RingwormTinea corporisTinea capitisTinea pedisRosaceaDilation of small facial blood vesselsScabies Contagious skin condition caused by mitesWarts Harmless growths caused by a virus20-51Apply Your KnowledgeMatch the following:___ Alopecia A. Dilation of small facial blood vessels___ Folliculitis B. Inherited autoimmune disorder___ Impetigo C. Hair loss___ Psoriasis D. Growths caused by a virus___ Rosacea E. Inflammation of hair follicles___ Warts F. Oozing skin lesions ANSWER:CFABDERight!20-52In Summary20.1 The functions of skin include protection, body temperature regulation, vitamin D production, sensation, and excretion.20.2 When the body is warm, the dermal blood vessels dilate, allowing heat to escape and cool the body. When the body is cool, the same vessels constrict, preventing the heat carried by blood from escaping, keeping the body warmer.20.3 The topmost layer of the skin is the epidermis. The dermis is the complex middle layer. The innermost layer, attaching the skin to muscle, is the subcutaneous layer.20-53In Summary (cont.)20.4 The amount of melanin affects and determines skin color. The amount of oxygen-carrying hemoglobin in our blood also affects skin color.20.5 Skin lesions are split among three main types: primary lesions such as macules and vesicles; secondary lesions include ulcers and keloids; vascular lesions involve blood vessels and include telangiectasias and ecchymoses. 20.6 The accessory organs of skin include hair follicles, arrector pili muscles, sebaceous glands, sudoriferous glands, and keratin-filled nails. 20-54In Summary (cont.)20.7 Injured skin becomes inflamed from dilating blood vessels which leak and cause swelling. A blood clot is formed, which is replaced by a scab, which is then replaced by collagen fibers that produce scar tissue.20.8 Skin loses elasticity with aging as well as the youthful glow because of the loss of collagen and elastin fibers. The loss of melanin also causes graying and thinning of the hair. The loss of adipose tissue and decreased number of sudoriferous glands makes it difficult to readily adjust to temperature changes.20-55In Summary (cont.)20.9 First-degree burns affect only the epidermis and are known as superficial burns. Second-degree burns or partial thickness burns involve both the epidermis and dermis. Third-degree or full-thickness burns affect all skin layers and underlying structures, including muscle and bone. 20.10 There are three types of skin cancer: basal cell, squamous cell, and malignant melanoma. Signs of skin cancer vary, as do the treatment methods for each type.20-56In Summary (cont.)20.11 Common skin disorders: the signs, symptoms, and treatments for these conditions are found in the Pathophysiology section at the end of the chapter.20.12 ABCDE is the acronym used to remember the signs of possible melanoma when looking at suspicious moles on the body. A = Asymmetry, B = Border, C = Color, D = Diameter, and E = Evolving.20.13 The seven warning signs of cancer are: C = Change, A = A sore, U = Unusual, T = Thickening, I = Indigestion, O = Obvious change, and N = Nagging cough.20-57We may have different religions, different languages, different colored skin, but we all belong to one human race. ~ Kofi AnnanEnd of Chapter 20