IB BIOLOGY

1. The Male And FemaleThe Male And Female
ReproductiveReproductive
SystemsSystems
(Let’s Keep it clean,(Let’s Keep it clean,
people!)people!)

2. Sex DeterminationSex Determination
 In most animals cells are produced in thisIn most animals cells are produced in this
ways:ways:
 A gene (SRY) on the Y chromosomeA gene (SRY) on the Y chromosome
causes embryonic gonads to developcauses embryonic gonads to develop
testes and secrete male hormonetestes and secrete male hormone
 SRY codes for a DNA binding protein TDFSRY codes for a DNA binding protein TDF
(Testis Determining Factor)(Testis Determining Factor)
 TDF causes other male factors to beTDF causes other male factors to be
expressedexpressed

3. Male ReproductiveMale Reproductive

4. Parts to the SystemParts to the System
 PARTS AND FUNCTIONS:PARTS AND FUNCTIONS:
 In ScrotumIn Scrotum
– TestesTestes – produce sperm in tightly coiled tubes:– produce sperm in tightly coiled tubes:
Seminiferous TubulesSeminiferous Tubules - meiosis- meiosis
– Interstitial CellsInterstitial Cells – in between seminiferous tubules:– in between seminiferous tubules:
produce TESTOSTERONEproduce TESTOSTERONE
– Epididymis –Epididymis – stores maturing spermstores maturing sperm
 TubesTubes
– Vas DeferensVas Deferens – carries sperm from epididymis to– carries sperm from epididymis to
urethra.urethra.
– UrethraUrethra – in penis. Exit point for sperm– in penis. Exit point for sperm
 Food and TravelFood and Travel --
– Seminal Vesicles – releases “sugars”Seminal Vesicles – releases “sugars”
– Prostate Gland – releases alkaline solutionProstate Gland – releases alkaline solution
– Cowper’s Gland – fluid to lubricate urethra, flush outCowper’s Gland – fluid to lubricate urethra, flush out
urineurine


6. HORMONES and NEGATIVEHORMONES and NEGATIVE
FEEDBACKFEEDBACK
 GnRH stimulates the pituitary to release LH and FSHGnRH stimulates the pituitary to release LH and FSH
 LH stimulates the production of testosterone.LH stimulates the production of testosterone.
 FSH works on “sertoli’ cells to provide nourishment forFSH works on “sertoli’ cells to provide nourishment for
sperm.sperm.
 Sertoli cells produce a hormone “inhibin” which inhibitsSertoli cells produce a hormone “inhibin” which inhibits
the pituitary and hypothalamus resulting in lower levelsthe pituitary and hypothalamus resulting in lower levels
of FSHof FSH
 HIGH LEVELS OF TESTOSTERONE PRODUCESHIGH LEVELS OF TESTOSTERONE PRODUCES
NEGATIVE FEEDBACK ON THE PITUITARY GLANDNEGATIVE FEEDBACK ON THE PITUITARY GLAND
DECREASING LEVELS OF LH (ICRH).DECREASING LEVELS OF LH (ICRH).

9. Female Reproductive SystemFemale Reproductive System

11. Parts and FunctionsParts and Functions
 Parts and Functions:Parts and Functions:
– OvariesOvaries –eggs produced in cavities:–eggs produced in cavities:
FOLLICLES. Released at OvulationFOLLICLES. Released at Ovulation ..
– OviductOviduct –– passageway for egg. SITE ofpassageway for egg. SITE of
fertilizationfertilization
– Uterus –Uterus – muscular, pear shaped. Holdsmuscular, pear shaped. Holds
developing organismdeveloping organism
– Cervix –Cervix – lower end of uteruslower end of uterus
– Vagina –Vagina – entry point for sperm. Exitentry point for sperm. Exit
point for Fetus. Birth Canal.point for Fetus. Birth Canal.

13. Menstrual CycleMenstrual Cycle
LH FSH
estrogen progesterone
Follicle Stage
ovulation
Luteal Stages
menstruation

14.  GeneralGeneral: Hormones from Glands control cycle:: Hormones from Glands control cycle:
– Hypothalamus(in brain): GnRH…….secreted toHypothalamus(in brain): GnRH…….secreted to
Pituitary:Pituitary:
 FSH –FSH –
– Stimulates growth of eggStimulates growth of egg
– Stimulates secretion of estrogenStimulates secretion of estrogen
 LH –LH –
– Stimulates ovulationStimulates ovulation
– Stimulates empty follicle to convert to corpus luteumStimulates empty follicle to convert to corpus luteum
– Stimulates corpus luteum to secrete estrogen and progesteroneStimulates corpus luteum to secrete estrogen and progesterone
– OvaryOvary
 EstrogenEstrogen
– Stimulates repair and growth of the uterusStimulates repair and growth of the uterus
 ProgesteroneProgesterone
– Stimulates and maintains growth of the uterine liningStimulates and maintains growth of the uterine lining

15. Hormones: – and + feedbackHormones: – and + feedback
 ESTROGENESTROGEN
– Negative feedback on pituitary to block FSHNegative feedback on pituitary to block FSH
release.release.
– Positive feedback on pituitary to signalPositive feedback on pituitary to signal
release of LHrelease of LH
 ProgesteroneProgesterone
– Negative feedback to block FSH releaseNegative feedback to block FSH release
– Negative feedback to block LH releaseNegative feedback to block LH release

16. Stages of MenstruationStages of Menstruation
 MenstruationMenstruation – (5 days)– (5 days)
– Egg not fertilizedEgg not fertilized
– Inner Uterine lining (endometrium) breaks down and passes out of theInner Uterine lining (endometrium) breaks down and passes out of the
vagina(with the egg).vagina(with the egg).
 Follicle StageFollicle Stage – (9 days)– (9 days)
– FSH production increasesFSH production increases
– Follicles in ovaries develop. (oocyte)Follicles in ovaries develop. (oocyte)
– Estrogen secreted to heal, repair, and thicken endometrium with bloodEstrogen secreted to heal, repair, and thicken endometrium with blood
vesselsvessels
 OvulationOvulation – Middle of Cycle--- 1 day– Middle of Cycle--- 1 day
– High level of estrogen decreases FSH and stimulates secretion of LHHigh level of estrogen decreases FSH and stimulates secretion of LH
– High level of LH – Follicle ruptures and egg is released.High level of LH – Follicle ruptures and egg is released.
 Corpus Luteum StageCorpus Luteum Stage – ( 13 days)– ( 13 days)
– Corpus LuteumCorpus Luteum is produced in ruptured follicle…stimulates progesteroneis produced in ruptured follicle…stimulates progesterone
production.production.
– Maintains endometrial growth.Maintains endometrial growth.
– Egg implantation if fertilization takes placeEgg implantation if fertilization takes place

18. William HarveyWilliam Harvey
 Again……Again……
 Tested “Seed and Soil” theory of AristotleTested “Seed and Soil” theory of Aristotle
 READ…….READ…….

19. In Vitro FertilizationIn Vitro Fertilization

20. In vitro fertilizationIn vitro fertilization
 Approximately 1 of 6 couplesApproximately 1 of 6 couples
 Used mainly as a way to overcomeUsed mainly as a way to overcome
a female infertility (physiological)a female infertility (physiological)
issue: blocked oviducts or timelyissue: blocked oviducts or timely
ovulationovulation
 Can be used in the case of lowCan be used in the case of low
sperm count.sperm count.

21. In Vitro FertilizationIn Vitro Fertilization

22. IVF ProcessIVF Process
1.1. Drug given to stop menstrual cycle.Drug given to stop menstrual cycle.
2.2. Large doses of FSH given – 2 weeksLarge doses of FSH given – 2 weeks
3.3. HCG given 48 hours before collection – matures eggsHCG given 48 hours before collection – matures eggs
4.4. Man provides semen.Man provides semen.
5.5. Eggs extracted through the vaginaEggs extracted through the vagina
6.6. Each egg is mixed with some sperm in a petri dish –Each egg is mixed with some sperm in a petri dish –
incubated 24 hoursincubated 24 hours
7.7. Check to see if fertilized!Check to see if fertilized!
8.8. Embryo’s selected and placed in uterusEmbryo’s selected and placed in uterus
9.9. Wait approximately 2 to 3 weeks and take pregnancyWait approximately 2 to 3 weeks and take pregnancy
test – implantationtest – implantation
10.10. Scan as normal for any developmental issuesScan as normal for any developmental issues

23. Ethical Issues of IVFEthical Issues of IVF
Pro:Pro:
 Environmental infertilityEnvironmental infertility
will not affect offspringwill not affect offspring
 Not developed – no painNot developed – no pain
to embryoto embryo
 Genetic screening beforeGenetic screening before
transferringtransferring
 Parents have strongParents have strong
desire for childdesire for child
Against:Against:
 Fate of extra embryos?Fate of extra embryos?
 Long term storage ofLong term storage of
embryos – stem cells?embryos – stem cells?
 Multi pregnancy placesMulti pregnancy places
stress on familystress on family
 ExpensiveExpensive
 High rate of failureHigh rate of failure
 religiousreligious

24. Puberty!Puberty!
 MaleMale
– Secretion ofSecretion of
testosteronetestosterone
increases!increases!
– Growth of hair,Growth of hair,
under arm, pubic,under arm, pubic,
facialfacial
– Lengthening of theLengthening of the
penis!penis!
– Deep voice!Deep voice!
– More musculature!More musculature!
 FemaleFemale
– Increased secretionIncreased secretion
of estrogen andof estrogen and
progesteroneprogesterone
– Growth of hair:Growth of hair:
underarm and pubicunderarm and pubic
– Enlargement ofEnlargement of
breastsbreasts

25. ENDEND