Body BugsNOVA | Bugs That Live on You
Follicular Mites found in all hair folliclesDust Mites found on your body, your bed, any fluffy surface that you spend time with
Normal Skin Color DeterminantsSlide 4.14Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsDetermined by a combo of:Types of pigments presentBlood circulationStratum corneum thickness
Normal Skin Color DeterminantsSlide 4.14Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsMelaninYellow, brown or black pigments produced in melanocytes found in stratum basale transferred to keratinocytesLocal accumulations form freckles & pigmented molesAmount of melanin produced depends upon genetic and exposure to sunlightSolar elastosis clumping of elastin fibers = leathery looking skin
Slide 4.14Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsCaroteneOrange-yellow pigment from some vegetablesVitamin A precurser vitamin A forms retinal which is needed for sightAccumulates in adipose and stratum corneum cellsNormal Skin Color Determinants
Normal Skin Color DeterminantsSlide 4.14Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsHemoglobin & blood circulationRed coloring from oxygenated blood cells in dermis capillariesOxygen content determines the extent of red coloringMore obvious in fair skinned individuals
Blood flowVasodilation causes increase in flowVasoconstriction causes decrease in flow
Skin as a DiagnosticSlide 4.14Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsSkin color is influenced by emotional & disease states: You should know the states that cause these.Cyanosis bluish color - lack of oxygenErythema redness heat, inflammation, feverAdd this -Pallor paleness lack of blood flowJaundice yellowish color liver damageBronzing bronze (tan) Addisons diseaseHematomas black & blue blood under skin
Hair AnatomySlide 4.19Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsCentral medullaCortex surrounds medullaCuticle on outside of cortexSingle layer of overlapping cellsSplit ends cuticle flakes off fibers in cortex fray outFigure 4.7b
Hair anatomyHair shaft above skinHair root below skin
Appendages of the SkinSlide 4.18Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsHairShaft projects from skinAdd in margins: Shape determines hair curlinessFlat = curlyOval = wavyRound = straightFigure 4.7c
Hair FollicleSlide 4.18Hair - Extends into dermis & hypodermisProduced by hair bulb- expanded endPapilla contains capillaries in bulb for hair nourishment (fix in notes!)Matrix = growth zone directly surrounds papillaFigure 4.7c
Associated Hair StructuresSlide 4.20Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsArrector pilliSmooth muscle regulated by emotionsContraction pulls hair upright - Normally at angleFigure 4.7a
Arrector Pili Muscle
Hair ColorSlide 4.19Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsCaused by proportions of 3 types of melaninDetermined by geneticsMelanin is replaced by air bubbles in gray/white hair causes different textureFigure 4.7b
Hair TypesSlide 4.20Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsVellus hair softer body hairTerminal hair coarser hair found in axillary & anogenital regions & other body regionsLanugo newborn baby fuzzFigure 4.7a
Hair GrowthSlide 4.20Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsInfluenced by (in order):Nutrition: main influencehormonesBlood flowFigure 4.7a
Thought Question: know the answers to these questions!!Why is the hair on your head longer than the hair in your eyebrows?
Why does some hair fall out every day?
Approx 100 hairs per day are lost from your head! That is why your sink is stopped up!
Androgenetic Alopecia Slide 4.20Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsMale pattern baldnessSex linked, recessive traitPunnett Square!Figure 4.7aCauses thinning hair in women
Androgenetic AlopeciaIncreased activity in androgen receptors causes hair loss & increases other health risks such as coronary heart disease and prostate cancer in men and polycystic ovary syndrome in womenTerminal hair replaced by vellus hair -progresses posteriorlyTreatment: drugs that inhibit testosterone production (Rogaine, Propecia)
FYI: Polycystic Ovarian SyndromeMore on these topics when we study the Endocrine System
Imbalance: FYIThinning hair can be caused by an abundance of factors.Heterozygous traitsNutritionMedicationsStress (affects nutrition & hormones)HormonesPhysical factors
Appendages of the SkinSlide 4.21Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsNails: Just know diagram & these imp. facts add to diagram:Scale-like modifications of the epidermisHeavily keratinizedStratum basale extends beneath the nail bed to form nail matrixWhich is responsible for growthLack of pigment makes them colorless
Nail StructureKnow all parts labeled on diagramWhy is lunula white?What happens if matrix is damaged?
Sweat GlandsSlide 4.16Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsSudoriferous (sweat) glandsThree typesEccrine glandsWidely distributed in skin: abundant on palms, soles, foreheadOpen via duct to pore on skin surfaceSweat composition: mostly water with a slightly acidic 4-6 pHFunction: thermoregulation
Sweat GlandsSlide 4.17Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsApocrine glands (also sudoriferous) Ducts empty into hair follicles Found mainly in anogenital & axillary regionBegin to function at puberty due to hormonesOrganic contents: Fatty acids and proteins can have a yellowish color that stains clothesOdor is from associated bacteria
Sweat GlandsSlide 4.17Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsCeruminous glands
Modified apocrine gland Found in outer 1/3 of ear canalProduce ear wax to trap invaders
Appendages of the SkinSlide 4.15Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsSebaceous glands (all over except palms and soles of feet)Produce oil for waterproofingLubricant for skin & kills bacteriaMost with ducts that empty into hair folliclesGlands are activated at puberty: stimulated by hormones
ImbalancesUpper right hand box in notes;Acne active infection of sebaceous glandsWhitehead - Sebaceous gland duct blocked by sebumBlackhead sebum oxidizes, dries, and darkensSeborrhea cradle cap Over activity of sebaceous glands in infants
Protection - biologicalBiological cells macrophages & Langerhans cells engulf invaders.
Protection - mechanicalMechanical physicalContinuity skin is made impermeable through the tight junctions & desmosomesKeratin physically blocks the passage of water and water soluble substancesFYI: Molecules that can pass through your skin:Lipid soluble O2, CO2, ADEK, steroids, nicotine, & other transdermal medicationsOleoresins poison ivy & poison oak, etc you have less than 10 min to wash it off!
Protection - ChemicalChemical Skin secretions: tears, sweat, oil lower pH and contain lysozyme (chemical that lyses cells)Melanin pigment shield against UV radiation
ExcretionLimited amounts of nitrogen containing wastes (most is excreted in urine unless you have a kidney disorder in which case urea will be excreted in small amounts through skin)Sodium chloride through sweatWater through sweatHeat through sweat
Homeostasis of Body TemperatureHeat production chief determinant is muscle activityHeat loss/gain80% of heat transfer is through the skin the rest is through the mucosa (dogs are opposite!)Regulated by vasoconstriction & vasodilation since heat is carried primarily in the water content of the blood (reminder: on page 1 of notes)
Understand what is happening in these diagrams!!
Vitamin D ProductionVitamin D is important in the uptake of Calcium from the food you eat.Ca has to be absorbed from your stomach into the blood to go anywhereCholesterol molecules when exposed to UV light become a Vitamin D precurserPrecurser becomes active in the liver & kidneys
Sensation skin receptorsDont need to memorize Free nerve ending = pain Meissners corpuscles = discriminating touch, light pressure (think fly on your arm)Krauses coldRuffinis heatMerkel Disc Medium pressurePacinian corpuscle Deep pressureSee diagram in notes
End of Quiz 2 MaterialNow Study!