2Body Membranes-Functions Line or cover body surfacesProtect body surfacesLubricate body surfaces
3Epithelial MembranesMade of epithelium connected to underlying connective tissueSkinCutaneous membraneExposed to air = Dry membraneMade of keratinized stratified squamous epithelium
4Epithelial Membranes, cont. Mucous membranesType of epithelium depends on location of membraneMost are stratified squamous OR simple columnarLines all body cavities open to exteriorRespiratory tractDigestive tractUrinary & Reproductive tractsWet membranes (bathed in secretions continuously)Underlying connective tissue is lamina propria
5Epithelial Membranes, cont. Serous MembranesSimple squamous tissue on areolar tissueLine cavities that are closed to exteriorOccur in pairsParietal layer-lines wall of a cavityVisceral layer-covers the outside of the organs inside the cavityLayers separated by fluid secreted by both membranesAllows organs to slide easily across cavity walls and each otherReduces friction (good for heart pumping, stomach churning, etc)Peritoneum-lining of abdominal cavity/covers organsPleura-surrounds lungsPericardium-surrounds heart
7Connective Tissue Membranes Synovial MembranesMade of areolar tissue-NO epithelial cellsLine joint capsulesProvide smooth surfaceSecrete fluid for lubrication (reduces friction)Also provide cushion for movements of tendons over bonesTendon sheath
8Integumentary System AKA…SKIN! AKA…Cutaneous membrane AKA…Integument Means “covering”Keeps water and nutrients IN the bodyKeeps water and other things OUTWe don’t get waterlogged when we shower or swim!
9Skin Functions Protects body from: Mechanical damage (bumps) Physical barrier and pressure receptorsChemical damageImpermeable cells; pain receptorsBacterial damageSkin secretions acidic; inhibit bacteriaUV radiationContains melaninThermal damageHeat/cold damageHas heat/cold/pain receptorsDessicationDrying out
10Skin Functions, cont. Aids in heat loss/retention Activates sweat glands and allows blood to flush into capillaries for heat lossNot allowing blood to flush into capillaries for heat retentionHelps excrete urea and uric acidSweat glandsMakes vitamin DSunlight converts cholesterol in skin to vitamin D
11Skin Structure Epidermis Outer layer Keratinized stratified squamous cellsNo blood supply of its own (avascular)DermisDense connective tissueCan separate from epithelium due to burns/frictionCauses blistersHypodermis (Subcutaneous Tissue)Technically…not part of skinAdipose (fat)Anchors skin to underlying organsShock absorberInsulates deeper tissues from extreme temp. changes
12Epidermis Layers Stratum basale Stratum spinosum Stratum granulosum Deepest layerNext to dermisCells are undergoing mitosisAKA Stratum germinativumCells get nutrients via diffusion from dermisCells get pushed up to move farther away from nutrient supplyStratum spinosumStratum granulosum
13Epidermis Layers, cont. Stratum lucidum Stratum corneum Clear, flattened cells full of keratinOnly in areas where skin is hairless and extra thickPalms of handsSoles of feetStratum corneumOutermost layerShingle-like cellsDead cellsProvides protective “coat” for bodyRubs/flakes off slowlyWe have a totally new epidermis approximately every month!
14Melanin Pigment produced by melanocytes In stratum basaleExposure to sunlight causes melanocytes to make melaninMore melanin = more skin pigmentation = TANAmount of melanin produced depends on:Amount of sun exposureGeneticsFreckles/MolesConcentration of melanin in one spot
15Dermis “Hide” Strong, stretchy, holds body together Two regions Papillary layerContains fingerlike projections “dermal papillae”Has capillary loops for nutrient supplyPain/touch receptorsMakes up our fingerprints (whorls, ridges)Reticular layerDeepest skin layerContains blood vessels, sweat glands, oil glandsHas pressure receptors
17Skin Color Determination Amount/kind of melanin in epidermisCan be yellow, reddish brown, or blackAmount of caroteneYellowish-orange pigment (think carrots)If you eat LOTS of foods this color, your skin will look this color also!HemoglobinProtein in red blood cells-carries oxygenLots of melanin = brown toned skinOxygen rich hemoglobin causes skin to look pinkWhen Caucasians look “flushed”
18Imbalances Abnormal yellow skin tone Can be due to liver disorder CyanosisWhen oxygen content in blood is lowBluish-tinted skin (“cyan”)ErythemaRedness/”flushing”Caused by blood rushing to capillaries near skin’s surfacePallor/blanchingPale skinCan be due to anemia, low BP, impaired blood flowJaundiceAbnormal yellow skin toneCan be due to liver disorderBruisesSites where blood has escaped from circulation and clottedTendency toward unusual bruising could mean vit. C deficiency or hemophilia
19Skin Appendages Cutaneous Glands Exocrine glands Release secretions to surface of skin through ductsTwo types:Sebaceous glandsSweat glands
20Sebaceous (oil) Glands All over skin EXCEPT hands/feetDucts empty into hair follicleRelease sebumOily substance and cell fragmentsLubricantKeeps skin soft, keeps hair from being brittleAntibacterial propertiesGlands become more active during pubertyPimples!WhiteheadCaused by blocked sebaceous glandBlackheadsWhen material inside whitehead dries outCradle cap (seborrhea)In infantsSebaceous glands are overactiveLooks like lots of oily dandruff on scalp
21Sweat Glands (Sudoriferous Glands) Eccrine GlandsMore numerous/all over bodyOpen to pores on skin surfaceProduce sweatImportant for heat regulationApocrine GlandsOnly found in axillary and genital areasLarger than eccrine glandsDucts empty into hair follicles
22Sweat Composition Mostly water Waste products Fatty acids and proteins (from apocrine glands only)ColorClear (eccrine)Milky white/yellowish (apocrine…due to FA’s and proteins)FunctionHeat regulation (gets rid of excess heat)Waste excretionAcidic-naturally inhibits bacteriaOdorSweat is ODORLESS!!The smell is from bacteria on skinWhen bacteria use sweat for nutrients, it is smelly!
23Skin Appendages Hair Produced by hair bulb Made of keratinized epithelial cells (dead…mostly protein)Color comes from pigment in melanocytesFound everywhere EXCEPT palms, soles, nipples, lips
24Hair Anatomy Medulla Central core Cortex Surrounds medulla Cuticle Outermost layerSingle layer of overlapping cells (like shingles)Has the most keratinProvides strengthSplit Ends?Caused when cuticle is worn away at the tip of the hair shaft…keratin frizzes out…hair “splits”
25Other Hair-Related Structures Hair FollicleInner epidermal sheath= hairOuter dermal sheath= connective tissueSupplies blood to epidermisArrector piliSmooth muscleConnects hair follicle to dermisWhen contracted, we see “goose bumps” and hairs are pulled uprightSebaceous glands
26Skin Appendages Nails Modification of epidermis Scale-like Contain lots of keratinMostly non-living materialStratum basale under nail bed resposible for growthColorlessNo pigmentAppear pink due to blood supply in underlying dermis
27BurnsTissue damage/cell death caused by heat, electricity, UV radiation (sunburn/tanning bed), chemicalsCan result in life-threatening problemsDehydration-lose fluid supply, electrolyte imbalanceLeads to kidney shutdown and circulatory shockLost fluids must be replaced immediately!
28Burns Rule of Nines How to estimate fluid loss from a burn Divides body into different regions, each being 9% (except genital area is 1%)
29Burn Classification First-degree Second-degree Third-degree Only epidermis is damagedRed, swollenRegeneration occursEx: sunburnSecond-degreeDamage to epidermis and upper dermisRed, painful, blistersThird-degreeFull-thickness burnGrayish white or black (looks charred)Destroys nerve endingsNot painfulRegeneration NOT possibleMust use skin grafting
31Critical Burns Over 25% of body has second-degree burns Over 10% of body has third-degree burnsThere are third-degree burns on face, hands, or feetFacial burns dangerousPossible burned airwaysCan swell, cause suffocationJoint injuriesScar tissue can limit joint mobility
32Skin Cancer Most common type of cancer Two Types Benign Risk factors: Overexposure to UV radiation (sun/tanning bed)Frequent skin infections or chemical irritationTwo TypesBenignDo not spreadMalignantMetastasizes (moves) to other parts of body
33Skin Cancer Basal Cell Carcinoma Squamous Cell Carcinoma Least malignantMost commonOccur most often on sun-exposed areasSlow-growing99% have full cure if lesion is removed surgicallySquamous Cell CarcinomaScaly, red; eventually forms shallow ulcer with raised borderOccurs most often on scalp, ears, hands, lipFast-growingGood chance of cure if removed surgically or use radiation therapy
34Skin Cancer Malignant Melanoma Cancer of melanocytes (cells that make melanin)5% of skin cancersOften deadlyCan begin anywhere there is pigmentDevelops spontaneously, some from moles50% survival rateExamine skin for new moles or pigmented spots periodicallyUse ABCD Rule of Detection
35ABCD Rule of Detection (A) Asymmetry Two sides of mole do not match (B) Border irregularityBorders of mole/lesion are not smooth(C) ColorSpot has areas of different colors instead of being one color throughout(D) DiameterSpot larger than 6mm (larger than pencil eraser)