FemaleReproductiveSystem

Lesson10

LearningGoals

1. Whatarethefivehormonesinvolvedinthefemalereproductivesystem?

2. Understandthefour phasesofthemenstrualcycle.

HumanReproductiveSystem

FemaleReproductiveSystem

FemaleAnatomy

• Ovaries– producehormonesestrogenandprogesterone• Siteofeggdevelopmentandovulation

• Fallopiantubes(oviducts)– carryovumfromovarytouterus

• Uterus–organwherefetusdevelops

• Cervix– separatesvaginafromuterus

• Vagina– providesapassageforspermandmenstrualflow

OogenesisandOvulation• Oogenesis – productionofanegg

• Ovariescontainsmallgroupsofcellscalledfollicles• Folliclescontaintheeggandsecreteestrogen

• Duringovulation,theoocyteisreleased• Folliclecellsturnintothecorpusluteum

FemaleHormones

• Estrogen – steroidhormone• Maintenanceoffemalereproductivesystem• Developmentofsecondarysexcharacteristics(e.g.breastdevelopment,thegrowthofbodyhair,thewideningofthepelvis,andthedevelopmentofthesexdrive)

• Progesterone – steroidhormone• ControlledbyLHandFSH• Preparesuterusforimplantationoffertilizedegg

MenstrualCycle

• Preparationforpregnancy

1. Flowphase– day1-5

2. Follicularphase- day6-13

3. Ovulatoryphase- day14

4. Lutealphase- day15-28

FlowPhase(1-5)• Sheddingoftheendometriumliningmarkstheflowphase• Tissuethatlinestheuterinewall• Richwithbloodvessels

• LHandFSHreleasedbytheanteriorpituitary• Stimulatedbythehypothalamus(GnRH)• FSHstimulatestheeggtodevelop• Formsafollicle

• Endometriumliningbeginstogrowagainasthemenstrualflowceases

Follicularphase(6-13)

• FSH andLH causedevelopmentoffollicleswithinovary

• Estrogenissecreted• Estrogenhasanegativefeedbackeffectontheanteriorpituitary• InhibitsthesecretionofFSH

Ovulatoryphase(14)

• HypothalamusandpituitaryglandreleasesaburstofLHtotriggerovulation(LHsurge)

• Eggburstsfromovary• Follicleà corpusluteum

• Afterovulation,estrogenlevelsdeclineandprogesteronelevelsrise• ManyPMS(premenstrualsyndrome)symptomscan

ariseduetoahigherthannormalestrogentoprogesteroneratio

LutealPhase(15-28)

• Developmentofcorpusluteummarksthelutealphase• Corpusluteumproducesestrogenandprogesterone

• Progesterone– stimulatesendometriumandpreparesuterusforfertilizedegg• Inhibitsovulationanduterinecontractions

• Corpusluteumdegeneratesiffertilizationdoesnotoccur(duetolowlevelsofLH)• Estrogenandprogesteronedecrease• Causeweakcontractionsà endometriumpullsawayfromtheuterus(beginflowphase)

Pregnancy

• Iffertilizationoccurs,theeggwillimplantandembryowillbegintoreleasehCG (humanchorionicgonadotropin)

• hCGkeepscorpusluteumfrombreakingdown

• Corpusluteumpreventsmenstruationfromoccurringandkeepsestrogenandprogesteroneathighlevelstomaintainuterineliningandpreventmenstruation

HormonalControl

• Hypothalamus secretesGnRH–signalspuberty

• GnRHcausesanteriorpituitary toreleaseFSHandLH

• FSHcausesfollicle togrow

• LHcausesovulation andmaintenanceofcorpusluteum

•Negativefeedback• Highlevelsofestrogeninhibits releaseofFSH

•Positivefeedback• Highlevelsofestrogenstimulates releaseofLH

Homework

•CaseStudy:ChemicalEric

•HandoutQuestions