1/8/2016

1

(Adapted from: Dale McKinnon, LU, 2009)

Eugene Ben-Awuah, PhDBharti School of Engineering

Laurentian University

Office: F211Tel: 705-675-1151 ext. 2195

Email: ebenawuah@laurentian.ca

Occupational Health EngineeringENGR 3126

Lecture 02 Human Body Systems and Hazards

Humanbodysystemsandhazards Hazardlocations

o Cellsanywhereo RoutesofEntry

Inhalation respiratorysystem(lungs);contact skin;ingestion intestines;injection bloodveins,nervesordermis

o InternalSystems circulatorysystem,centralnervoussystem,reproductivesystem

o RoutesofExit liver,kidneys,bladder

1/8/2016

2

MechanismsofentryoftoxicsubstancesIngestionInhalation

Contact Injection

TheHumanCell

Cytoplasm

Mitochondriaareresponsibleforcellularrespiration

Nucleusiscomposedofgeneticmaterial(DNA)

Cellmembraneregulatesfoodandchemicalsfromthebloodandwasteproducts

Cytoplasmcomprisesofthegellikesubstanceenclosedwithinthecellmembraneandthenucleus 25um

1/8/2016

3

Humanbodycontainstrillionsofcellso Specializedfunctions

redbloodcellstransportoxygen, whitebloodcells(phagocytes)produceantibodiestodefendagainstinfection,

livercellscontainenzymestoprotectthebodyagainstpoisonsandharmfulsubstances,

nervecellsgenerateandtransmitelectricalimpulsestocontrolthoughtsandmovement

Organsandtissuearecomprisedofbillionsofsimilarcells

Cellsarelivingandreproducebydividing Cellstakeinnutrients respiration

TheHumanCell

Hazardtocells CellDamage

o DNA(controlscellreproductionandspecializedfunction)canbedamaged

AbnormalGrowthorAbnormalFunction Manyphysicalandchemicalagentsareknowntocausecelldamage

Carcinogens,Mutagens,andTeratogens Otherchemicalandphysicalagentscauseavarietyofhealthandsafetyproblems

1/8/2016

4

RespiratorySystem Inhalationisacommon

pathforhazardoussubstancestoenterthebody

Lunghas3majorAreaso RespiratorySystemo ConnectiveTissueo Structurealveolar

macrophage HealthySeatedMale

o 3to4litresofgas/breatho 95%ofgasintheAlveoli

UpperAirwayso Nose,paranasalsinuses,

mouth,pharynx,andlaranyx

UpperAirways Bringinhaledairclosetobodytemperature(~37oC)(eitherbyheatingorcooling)

Increaserelativehumidityclosetosaturation Removesomesuspendedparticlesandcontaminantgases

1/8/2016

5

LowerAirways Designtoevenlydistributeinhaledairtothealveoli

Airwayssubdividedichotomouslyatthetracheainto17Stagesofpurelyconductiveairwaysendingattheterminalbronchioles

Theterminalbronchiolesleadtotherespiratorybronchioles;wallscontainthealveoli

Alveoli Severalhundredmillionperlung Provideadiffusingsurface(~70m2) O2andCO2 diffusesfromthealveolitothehaemoglobinin

bloodoveradistanceof1umto4uminabout0.3seconds CO2 diffusesfromhaemoglobininredcorpusclestothealveoli

ofthesamedistanceandtime Containmacrophagestocleansethealveoliofinsoluble

particlesthroughphagocytosisanddigestion

1/8/2016

6

Inhalation Mostdangeroussolidparticles/fibresare0.5to7uminsizeo Godeepintothelungandcandamage(scar)thealevolideepinthelung

o Scarringcausesdiseaseslikeasbestosis,silicosis,andcoalworkerpneumoconiosis

o Severeshortnessofbreath Gases,vapours,mists,andfumesenterthebloodstreamo Stimulatesthelungsdefencestoproducealargeamountofphlegm(ChronicBronchitis)

o Candestroythealveoli(Emphysemia) ExposuretoinhaledCarcinogenscancauselungcancer

Silica is found in many rocks, sand, and construction materials. Silica dust is produced while drilling these materials. You can get a lung disease called silicosis by breathing very small silica particles into your lungs. These particles can be seen only with a microscope.

1/8/2016

7

Emphysema,absestosis &silicosis

Carcinogens Agentsorsubstancesthatcausecancer Virtuallyalltypesofcellsarevulnerable Second(40%ofpopulationwillcontract)leadingcauseof

deathnexttoheartdiseaseandstroke Abnormalcellgrowthresultsinamalignant(Cancerous)

tumour Tumourenlargesandspreadstootherareas(secondarysites)

andcancausedeath ChemicalsintheworkplaceareknowntochangeDNA

(Carcinogens) Repeatedexposureisrequired(10to30yearsbeforecancer

develops) Cancermayhavestartedunknowntotheworker

1/8/2016

8

SomeknownorsuspectedcarcinogensAcrylonitrile Arsenic AsbestosBenzo (a)Pyrene (PAH) Beryllium BischloromethylEtherCadmium Chromium CigaretteSmokeCokeOvenEmissions HematiteOre IonizingRadiationIsopropylOil LeatherDust MustardGasNickel RadonGas VinylChlorideDieselParticulateMatters(DPM)

Isocyanates

Mutagens&Teratogens Mutagens

o Causechangestooneormorehereditaryfeaturesbymodifyinggenesinacell

o Example:IonizingRadiation Teratogens

o Causechangetoadevelopingfetuso Example:Thalidomide(NoLongerInUse)

1/8/2016

9

Largestorganofthehumanbodyandhasthelargestsurfacearea Protectsinternalorgansfromtheoutsideenvironment Outerlayercomposedofhardeneddeadcells Containssweatglandsthatcancoolthebodythrough

evapotranspiration

Containssebaceousglandsthatproduceoilswhichservetorepelwater

Capillarybloodvesselsarekeyincontrollingbodytemperatureo Openwhenhot(radiateheat,cool),constrictwhencold

Protectivelayerofoilsandproteinstopreventinjuryandpenetrationofharmfulsubstances

Somesubstances(e.g.solvents)penetrateskintobetransportedviacirculationsystemandbloodtootherpartsofthebody

TheSkin

Absorption Industrialskindiseaseaccountsfor50 75%ofallcompensationclaims

o Hazardoussubstancesabsorbedthroughtheskinandtraveltoanotherpartofthebodyviathelymphaticsystemorcirculatorysystem(important:leadedgasolineandinsecticides)

o Dermatitisismaindisease Canaffectthepointofabsorption SkinAbsorptionThroughtheFolliclesandGlands,alsoknownasappendageal

absorption,mayalsoexhibitreservoireffectsinwhichsubstancesmaybestoredwithintheglandsforabsorptionovertime

1/8/2016

10

Dermatitis Inflammationofskin Causedbyhundredsofworkplacesubstances

o Solvents(Paint),EpoxyResins(PlasticsManufacturing),Acids,CausticSubstances,Metals(MetalPlating),andMore

Redness,itchiness,orscalingofskin Twotypesofdermatitis

o PrimaryIrritationContactDermatitiso AllergicContactDermatitis

PrimaryIrritationContactDermatitis Acuteirritantcontactdermatitis.Thisis

oftentheresultofasingleoverwhelmingexposureorafewbriefexposurestostrongirritantsorcausticagents.Commonworkchemicals,whichcauseacuteirritantreactions,include:

Concentratedacids,e.g.sulphuric,nitric,hydrochloric,chromic,hydrofluoricacids

Strongalkali,e.g.calcium,sodium,potassiumhydroxide,wetconcrete,sodiumandpotassiumcyanide

Organicandinorganicsalts,e.g.dichromates,arsenicsalts

Solvents/gases,e.g.acrylonitrile,ethyleneoxide,carbondisulphide,mustine.

Chronic(cumulative)irritantcontactdermatitis.Thisoccursfollowingrepetitiveexposuretoweakerirritantswhichmaybeeitherwet,suchasdetergents,organicsolvents,soaps,weakacids,andalkalis,ordry,suchaslowhumidityair,heat,powders,anddusts.ChronicICDisduetoastepwiseprogressionofdamagetothebarrierfunctionoftheskin.

1/8/2016

11

AllergicContactDermatitis Allergiccontactdermatitis(ACD)isan

inflammatoryskindiseasethatiscausedbycontactallergens.

ThedamagetotheskinthatresultsinskineczemaiscausedbyTcellswhichrecognizethesecontactallergenswhenpresentedonskincellsandexertcytotoxiceffectsontheseskincells.

Contactallergenscanbeorganicchemicalsormetalionssuchasnickel.

Incontrasttoirritantswhicharechemicalsthathavedirecttoxiceffectsontheskinandcauseirritantcontactdermatitis(ICD),contactallergensmustinteractwithproteinsinordertoactivatetheimmunesystem.Theactivationoftheinnateimmunesystemisrequiredforsensitizationtocontactallergens.

ACD caused by textile dyes

Agentscausingcontactdermatitis

Agentscausingskincancer

Acrylics Chromates EpoxyResinsFormaldehyde Nickel ThiruamsPolyurethane

Pitch Arsenic UltraVioletLightAsphalt Tar XRaysCreosote Benzo(a)Pyrene(PAH) AnthraceneShaleOil CuttingOils Soot

1/8/2016

12

Ingestion/DigestiveSystem Extendsfromthemouthtotheanus

Ingestion,Digestion,Adsorption,andExpulsion

Smallintestineisresponsibleformostdigestionandabsorptionoffoodandwater

Largeintestinegenerallyabsorbsvitaminsandsalts

Ingestion

Toxicsubstancesenterthebodythroughthemouthordigestivetracko Toxicsubstancescanbeonfoodandindrinkso Smokinginadustyenvironment

Fromdigestivetracktobloodstreamtoliverorkidneys LiverandKidneystrytomakethesubstanceslessharmfultothebody(notalwayssuccessful)

Cleanlunchrooms,washhands,donotleaveunwrappedfood

1/8/2016

13

CirculatorySystems

CirculatorySystem Notindirectcontactwith

hazardousmaterialslikethelungs,digestivesystem,andskin

Transportshazardoussubstancestootherpartsofthebody(usefulsubstancesaroundthebody)

Secondaryinvolvementwithinhalation,absorption,ingestionroutesofentry

Primaryinvolvementwithinjectionrouteofentry

Nocellinthebodyismorethanafewmmfromthecirculatorysystem

1/8/2016

14

Hazardsforthecirculatorysystem Likefoodandoxygen,workplacetoxicsubstancesinthebloodcanreach

everycellinthebodythroughthecapillariesofthecirculatorysystem Inthelungs:

o Redbloodcellscontainaprotein(Haemaglobin)thatcarriesoxygentocellso Carbonmonoxidebindstohaemaglobin200to300timesmorereadily(high

levelscanresultindeath)o Lowerlevelsofrepeatedexposurecanaffecttheheartandcentralnervous

system Anemia

o Toxicsubstancescanattackredbloodcellsdirectlyorindirectlyo Anaemiaresultswhenatoxicsubstanceinterfereswiththeproductionofred

bloodcellsinthebonemarrowo Agents:

ArsineGas Cadmium SeleniumCopper Lead Gallium

Stibine Beryllium MercuryCompoundsBenzene Toluene

Injection Hospitalworkersandcontaminatedsyringeso Accidentallyinjectviruses

Diseasecanbecausedbysharingneedles Puncturewound

o Steppingonanail(cancausebloodpoisoning)o Canbecostlyifnottreatedwithantiseptico Slivers

Reportallinjuriesandhavethemtreated

1/8/2016

15

NervousSystem

NervousSystem Controlsmovement,thoughts,emotions,breathing,circulation,andorganfunction

Harmfulsubstancescanaffectitandthesefunctionscanbecomeimpaired

Examples:themetalsPbandHgo UncontrolledMoodSwingstoDeath

Alonglistofeffectsonnervoussystemofheavymetals:

http://www.incrediblehorizons.com/Toxic%20metal%20Chart%20&%20chelators.htm

1/8/2016

16

HazardstoNervousSystem Mostinjuriesarepermanent Damagetotheperipheralnervoussystemcansometimesbereversed

Toxicsubstancescaninterferewithnerveimpulsesandcausetremorsandlossoffeelings,reflexes,orsupplyofoxygentothebrain(dizziness,drowsiness)

SomesubstancestoxictothenervoussystemDepressionofSystem

BrainPoisoning OxygenDepravationtoBrain

NerveFunctionDisorders

Acetates CarbonDisulphide

AsphyxiatingGases(CO2)

OrganoPhosphatePesticides

Alcohols HydrogenCyanide

CO HeavyMetals

BromatedChemicals

HydrogenSulphide

Arsenic

ChlorinatedChemicals

Stibine Hg

Ethers PbKetones Mn

ThebrainispartoftheCentralNervousSystem

1/8/2016

17

ReproductiveSystem TestesandOvaries Producecellsthatallowustoreproduce Highlyspecialized Therefore,pronetodiseaseanddamagebyhazardoussubstances.

SpecifichazardstoreproductiveSystem Toxicsubstancescanresultindeformitiesand/ormiscarriagemayresultbecauseofaseverelydamagedembryo

Anaestheticgasescausehigherthannormalratesofmiscarriagesinfemalemedicalworkers

ReducedspermcountscanoccurinmalesexposedtoPborthepesticide,dibromochloropropane

Cancercausingsubstancesaffectthegeneticmaterialofthecellsandoftencausebirthdefectsandmiscarriages

1/8/2016

18

LiverandKidneys RoutesofExit

TheLiver

Detoxification mechanism

1/8/2016

19

Otherliverfunctions processingdigestedfoodfromtheintestine controllinglevelsoffats,aminoacidsandglucoseintheblood combatinginfectionsinthebody manufacturingbile storingiron,vitaminsandotheressentialchemicals breakingdownfoodandturningitintoenergy manufacturing,breakingdownandregulatingnumeroushormones

includingsexhormones makingenzymesandproteinswhichareresponsibleformostchemical

reactionsinthebody,forexamplethoseinvolvedinbloodclottingandrepairofdamagedtissues

Contains>50%ofbodysmacrophages:Kuppfercells Wasteproductswhicharenotexcretedbykidneysareremovedfromthe

bloodbyliver.Someofthempassintotheduodenumandthenintothebowelviathebileducts.

TheKidneys

1/8/2016

20

Kidneyfunctions Filtersubstancesintheblood(overamillionfilters) Depositedasurinetotubes(Tabules) Tabulesmonitoracidandwaterinthebodytokeepabalance Fromtabulestobladderforexitfromthebody Regulatethefluidbalanceinthebody.Youneedacertainamountof

waterinyoursystem nottoomuch,andnottoolittle.So,kidneyshelpmaintaintherightbalance.Ifthereistoomuchwaterinthebody,thekidneysproducemoreurine.Toolittlewaterresultsinlessurine.

Monitorelectrolytes(sodium,potassium,chloride,calciumandphosphorousbeingthemainelectrolytes)andbalancetheacidsandbasesinthebody

Controlbloodpressure Contributetotheproductionofhormones,suchasErythropoietinand

VitaminD.Erythropoietinstimulatesthebonemarrowtoproducetheredbloodcell.VitaminDpromotesstrong,healthybonesandhelpstomaintainnormalchemicalbalanceinthebody.