LE 46-12SpermatogoniumPrimary spermatocyte(in prophase of meiosis I)Mitotic division, producinglarge numbers of spermatogoniaMeiosis I completedDifferentiation and onset of meiosis ISecondary spermatocyteMeiosis IIEarlyspermatidsSpermatids(at two stages ofdifferentiation)DifferentiationSperm cellsNeckHeadMidpieceTailPlasma membraneMitochondriaAcrosome NucleusSertoli cellnucleusLumen ofSeminiferous tubuleCross sectionof seminiferoustubuleTestisEpididymisSeminiferous tubuleLE 46-9aBartholin’s glandVaginal openingVaginaCervix(Rectum)OviductOvaryUterus(Urinary bladder)(Pubic bone)UrethraShaftGlansPrepuceLabia majoraClitorisLabia minoraLE 46-9bVaginaCervixOviductOvariesUterusEndometriumFolliclesCorpus luteumUterine wallLE 46-11Primary germ cellin embryoMitoticdivisionPrimaryoocyteOvaryOogoniumDifferentiationOogoniumin ovaryPrimaryoocytewithinfollicleGrowingfollicleSecondaryoocyteCompletion of meiosis Iand onset of meiosis IIOvulationFirst polar bodyMature follicleEntry of spermtriggerscompletionof meiosis IISecond polar bodyOvumRupturedfollicleOvulatedsecondary oocyteCorpus luteumDegen-erating corpus luteumFig. 46-12gPrimordial germ cellMitotic divisionsOogoniumMitotic divisionsPrimary oocyte(present at birth), arrestedin prophase of meiosis ICompletion of meiosis Iand onset of meiosis IISecondary oocyte,arrested at metaphase ofmeiosis IIFirstpolarbodyOvulation, sperm entryCompletion of meiosis IISecondpolarbodyFertilized egg2n2nnnnnIn embryoFig. 46-12fOvaryPrimaryoocytewithinfollicleRupturedfollicleGrowingfollicleMature follicleOvulatedsecondary oocyteCorpus luteumDegeneratingcorpus luteumFig. 46-15OvaryUterusEndometrium(a) From ovulation to implantation(b) Implantation of blastocystCleavageFertilizationOvulation Cleavagecontinues The blastocystimplantsTrophoblastInner cell massCavityBlastocystEndo-metrium12345Fig. 46-16PlacentaUterusUmbilical cordChorionic villus,containing fetalcapillariesMaternal bloodpoolsMaternalarteriesMaternalveinsMaternalportionof placentaFetal arterioleFetal venuleUmbilical cordFetalportion ofplacenta(chorion)UmbilicalarteriesUmbilicalveinFig. 46-14aControl by hypothalamusInhibited by combination ofestradiol and progesteroneStimulated by high levelsof estradiolInhibited by low levels ofestradiolHypothalamusGnRHAnterior pituitaryFSHLHPituitary gonadotropinsin bloodLHFSHFSH and LH stimulatefollicle to growLH surge triggersovulationOvarian cycleGrowing follicleMaturingfollicleCorpusluteumDegeneratingcorpus luteumFollicular phaseOvulationLuteal phase(a)(b)(c)Days0 51014 15 20 25 28||| | ||| |––+Fig. 46-14bOvarian hormonesin bloodPeak causesLH surgeEstradiol levelvery lowEstradiolProgesteroneOvulationProgesterone and estra-diol promote thickeningof endometriumUterine (menstrual) cycleEndometrium0 51014 20 2528||| |||| |Days15Menstrual flow phase Proliferative phase Secretory phase(d)(e)LE 46-13HypothalamusAnterior pituitaryControl by hypothalamusPituitary gonadotropinsin bloodFSH LHFSHLHGnRHInhibited by combination ofestrogen and progesteroneInhibited by low levels ofestrogenStimulated by high levels of estrogenLH surge triggersovulationFSH and LH stimulatefollicle to growMaturefollicleGrowing follicleOvarian cycleCorpusluteumDegeneratingcorpus luteumFollicular phaseOvulation Luteal phaseProgesterone andestrogen secretedby corpus luteumEstrogen secretedby growing follicle inincreasing amountsProgesterone and estro-gen promote thickeningof endometriumPeak causesLH surgeOvarian hormonesin bloodEstrogen levelvery lowProgesteroneEstrogenEndometriumUterine (menstrual) cycleMenstrual flow phase Proliferative phase Secretory phaseDays28252015141050Fig. 46-18EstradiolOxytocinfromovariesInduces oxytocinreceptors on uterusfrom fetusand mother’sposterior pituitaryStimulates uterusto contractStimulatesplacenta to makeProstaglandinsStimulate morecontractionsof uterusPositive
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