(IP) sec 2: science notes 2021

Titleofcontents:)) HumanDigestiveSystem HumanSexualReproductiveSystem ChemicalBonding ChemicalChanges Forces EnergyWorkPower Electricity InteractionswithinEcosystems HumanDigestiveSystem -consistsofthealimentarycanalandtheassociatedorgans-alimentarycanalconsistofthemouth,oesophagus,stomach,smallintestine,largeintestine,rectumandtheanus(basicallyroutewherefoodpassesthrough)-associatedorgansincludesalivaryglands,pancreas,gallbladderandliver Functionsofthedifferentpartsofthedigestivesystem-Digestionoffoodbeginsinthemouth,andcontinuesinthestomachandendsinthesmallintestine

-Physicaldigestion(e.g.chewingandchurningactionofthestomach)helpstobreakfoodintosmallerpieces-Chemicaldigestionbyenzymeshydrolysesthefoodmoleculesintosimpler,moresolubleanddiffusiblemoleculessothattheycanbeabsorbedintothebloodstream Enzymes-substancesproducedbythebodythatspeedsuptherateofchemicalreactions,includingdigestion,biologicalcatalyst-ORWELLSbiologicalcatalyststhataltertherateofchemicalreactionsinourbodywithoutbeingchangedandarespecificinaction classofenzymes actson end(final)productsofdigestion carbohydrate(e.g.amylaseandmaltase) carbohydrates Simplesugars(e.g.glucose) protease proteins aminoacids lipase fats fattyacidsandglycerol structure functions mouth physicalandchemicaldigestionoccurshere!1. teethbreakfoodintosmallerpieces-increasesurfaceareatovolumeratioofthefoodwhichallowsittobedigestedfaster-easiertoswallow2. salivaryglandssecretesalivawhichcontainssalivaryamylase-amylaseisanenzymethatdigestsstarchtomaltose3. noproteinsorfatsdigestioninthemouth salivaryglands -produceandsecretesalivacontainingsalivaryamylase esophagus -amusculartubethatcontractsandrelaxesrhythmicallytopushthefooddownintothestomach stomach -stomachchurnstobreakfoodupandmixesitwithgastricjuice-gastricjuicecontainshydrochloricacidandprotease-hydrochloricacidkillsbacteria-proteasedigestsproteinsintosimplerproteins(polypeptides)-NOcarbohydrateorfatsdigestion pancreas 1. producespancreaticjuice-containsamylase,proteaseandlipaseforthedigestionofscratch,proteinsandfatsrespectively gallbladder -releasesbileintothesmallintestine-bileisproducedintheliverbutstoredinthegallbladder-bilebreaksupfatsintotinyfatdroplets-thisincreasesthesurfaceareatovolumeratiooffatsfordigestionbylipasetospeedupdigestion smallintestine -partiallydigestedfood(acidchyme)enteringfromthestomachmixedwithdigestivejuicesfromthepancreas,gallbladderandintestinalglands-foodiscompletelydigestedinsmallintestine

largeintestine -onlyfoodthatcannotbedigestedentersthelargeintestine-thecolonabsorbsremainingwateranddissolvedions-therectumstoresfecestemporarily anus -feces(containingundigestedfood)isexpelledfromthebodythroughtheanus Endproducts-arerelativelysmall-smallenoughtopassthroughwallsofsmallintestineandintothebloodvessels,tobedistributedtotheotherpartsofthebodybythecirculatorysystem-mostofthewaterconsumedisalsoabsorbedinthesmallintestine-theremainingwateranddissolvedionsareabsorbedinthecolon endproductofdigestion howtheyareusedbythebody glucose -glucoseisusedincellsduringrespirationtoreleaseenergy aminoacids -aminoacidsareusedbycellstomakeproteins,whichareusedforgrowthofnewcellsandrepairofdamagedtissues fattyacidsandglycerol -fattyacidsandglycerolcombineagaintoformfatswhicharestored-fatscanalsobeoxidisedtoreleaseenergy HumanSexualReproductiveSystem Puberty-aperiodofactivegrowth,whenanadolescentbecomesphysicallymatureandcapableofreproducing-duringpuberty,reproductiveorgansbecomematureandstarttoproducesexhormones,suchastestosteroneinmalesandoestrogenandprogesteroneinfemales-highamountsofgrowthhormonesarealsoproducedleadingtogrowthspurts-attheendofpuberty,boyswillhaveheavierbonesandanincreaseinmusclegrowthandgirlswillexperienceanincreaseintheamountoffattissuesatthebreasts,hipsandpubicregion

Malereproductivesystem Organ(s) Description/function Testis(plural:testes) Producesspermsandmalesexhormonessuchastestosterone Epididymis Storesinactivespermsfromtestisbeforetheyarereleasedintothespermduct Scrotum(scrotalsacs) Apairofpouch-likesacsthatholdthetestes.Theyhelptokeepthetestesbeyondthemainbodycavity,hencemaintainthematalowertemperaturethanbodytemperatureforhealthydevelopmentofsperms. Spermduct Thepathwaytravelledbyspermsaftertheyarereleasedfromthetestistotheurethra Prostategland Releasefluidsthatcontainnutrientsandenzymesthatareneededtoactivatethesperms.Themixtureofthisfluidandspermsiscalledsemen. Urethra Extendsfromtheurinarybladder,throughthepenis,totheoutsideofthe

bodywhereurineandsemenarepassedout. Penis Anerectileorganwithspongytissuesthatwillbefilledwithblood.Duringsexualintercourse,itentersthevaginatodepositsperm-containingsemen. Femalereproductivesystem Organ(s) Description/function Ovaries Produceeggs/ovaandfemalesexhormonessuchasestrogenandprogesterone.Matureeggsarereleasedfromtheovary. Oviduct(fallopiantube) Anarrowmusculartubeleadingfromtheovarytotheuterus.Matureeggsarereleasedfromtheovaryintotheoviduct.Fertilisationoccursinthisorgan.Themuscletissuesintheoviductwallcontractandrelaxtopushtheeggalongtheoviducttowardstheuterus Uterus(womb) Theorganinwhichthefoetusdevelopsduringpregnancy. Themuscletissuesinthewallsoftheuteruscontracttopushthefoetusoutduringbirth. Uterinelining(endometrium) Softinnerliningoftheuterus.Neededforembryoimplantation. Cervix Acircularringofmusclesatthelowerendoftheuterus.Thecervixcontractstokeepthefetuswithintheuterusduringpregnancy. Vagina(birthcanal) Theorganwheresemenisdepositedduringsexualintercourse. Vulva Theopeningofthevagina Sperm-head:containsnucleus,asmallamountofcytoplasm,andanenzyme-containingacrosome-middlepiece:containsnumerousmitochondria-tailorflagellum:enablesthespermtoswimtowardstheegg-producedthroughoutthelifeofasexuallymaturedmalehuman

Egg-atbirth,about70000potentialeggcellsarealreadypresentintheovaries-hasanucleus-relativelylargeamountofcytoplasm-cellsurfacemembranethatissurroundedbyanoutermembrane-cannotmoveonitsown;movedbythesweepingactionoftheciliaandthecontractionandrelaxationofmusclesinthewalloftheoviduct-eggsarereleasedintotheoviductsfromthetimeafemalereachespubertyuntilshereaches45-55yearsofage,andusuallyonlyonematureeggisreleasedeverymonth. comparisonchart(becausewhynot!) comparison sperm egg similarity bothcontainhalfasmanychromosomesasnormalbodycells differences releasedinmillions releasedoneatatime abletomove unabletomoveonitsown verysmall comparativelylarge verylittlecytoplasm alotofcytoplasm TheMenstrualCycle Days Events 1-5 Menstruation-thedischargeofbloodanddeadtissuesfromtheuterineliningthroughthevagina 6-13 Repairofuterinelining(endometrium) 14(+/-1) Ovulation-thereleaseofamatureeggfromtheovaryintotheoviduct 11-28 Growthandcontinuedthickeningofuterinelininginpreparationforimplantation -lengthofcyclemayvaryfrom21-33daysbutonaverageis28days-variationinlengthisnormal,butcanalsobeaffectedbyfactorssuchasstress,illnessandmalnutrition

-IFfertilisationdoesnotoccur,levelofestrogenandprogesteronewillstarttodecrease.-Whenhormonesreachalowlevel,uterineliningcannotbemaintainedandwillbeshedduringmenstruation.-IFfertilisationoccurs,uterineliningwillcontinuetothickenandbemaintainedinpreparationofimplantationofthefertilisedegg. Fertilisation-spermandeggmeet-spermpenetrateseggbyreleasingenzymesfromitsacrosometobreakdownpartoftheeggmembrane-onlyonespermallowedtomeetegg-oncesinglespermhasentered,theeggmembranechangessuchthatnootherspermcanpenetrateit-thenucleusofthespermfuseswiththenucleusoftheeggtoformthezygote,whichnowhasafullsetofchromosomes(46,2pairsof23) Developmentofembryo-Afterfertilisation,thezygotetravelsdowntheoviduct.-zygoteundergoesmultiplecelldivisioncyclesanddevelopsintoaballofcellscalledanembryo-embryoreachestheuteruswhereitgetsembeddedintheuterinelining,thisiscalledimplantation.-afterimplantation,theembryocontinuestogrowanddevelop,theplacentaformsfortheexchangeofsubstancesbetweenthefetusandthemother,fetusconnectedtoplacentabytheumbilicalcord-whenmajororgansareformed,embryonowupgradestobecomefetus.fetuswillcontinuetoincreaseinsizeuntilitisreadytobeborn-duringbirth,contractionsof