Days topic

Hormones and Sexuality Part 1APSY 214: Unit 31AdminNo office hours this Friday2Todays goalsAt the end of the today, you should be able toDistinguish between the major structures and hormones involved in the regulation of gonadal hormones Explain the process involved in the regulation of gonadal hormones, starting with the hypothalamus and its hormonesExplain how sexual differentiation occurs for:GonadsInternal reproductive ductsExternal reproductive organs3Todays goalsAt the end of the today, you should be able toDescribe the hormonal changes that occur during puberty and the effect they have on the bodyExplain the aromatization hypothesisSummarize what we understand about sexual differentiation in the mammalian brain, includingAromatization hypothesis and humansKey findings in the area

4Sample test questionSry protein triggers the development of:the testes. a Mllerian system. the penis. ovaries. 5Sample test questionThe aromatization hypothesis states that:Testosterone is directly responsible for masculinizing the brainMale and female brains are not differentiated (i.e. there are no sex difference in brain development)estradiol created in the brains of developing males from circulating testosterone masculinizes their brains. estradiol created in the brains of developing females from circulating testosterone feminizes their brains.

6The Neuroendocrine System7Regulation of gonadal hormonesHypothalamusGonadotropin releasing hormone (via veins)Anterior pituitaryGonadotropinsGonadsEstrogens, androgens, progestinsBody tissue8Goal reviewYou should now be able toDistinguish between the major structures and hormones involved in the regulation of gonadal hormones Explain the process involved in the regulation of gonadal hormones, starting with the hypothalamus and its hormones

9Sexual differentiation10Male or female?How do we become male or female?What role do sex hormones play?

?11Think about itA normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

12Think about itA normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

1:0013Think about itA normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

:3014Activity 2A normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

4:0015Activity 2A normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

3:0016Activity 2A normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

2:0017Activity 2A normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

1:0018Activity 2A normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

:3019Activity 2A normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

Times up!

20Activity 2 - AnswerA normal genetic female receives injections oftestosterone throughout fetal development. She will beborn with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

21Activity 2 - RecapLets walk through typical sexual developmentThere are three components. Differentiation of the:GonadsTestes and ovariesInternal reproductive ductsMale includes vas deferensFemale inclues uterus, fallopian tubesExternal reproductive organsMale penis, scrotumFemale clitoris, labia22Activity 2 - RecapGonads6 weeks after fertilizationBoth sexesPrimordial glandsMalesSry gene (Y chromosome) -> Sry protein -> primordial gonads -> testesFemalesNo Sry gene (no Y chromosome) -> no Sry protein -> primoridal gonads -> ovariesAdd testosterone?

23Activity 2 - RecapInternal Reproductive Ducts6 weeks after fertilizationBoth sexes Wolffian and Mllerian systemsMaleTestes -> androgens -> development of WolffianTestes -> Mllerian-inhibiting substance -> degeneration of Mllerian systemFemaleNo testes -> no androgen -> no development of WolffianAdd testosterone?

24Activity 2 - RecapExternal reproductive organs2nd month of pregnancyBoth sexes biopotential precursorMales Testosterone -> male external genitaliaFemalesNo testosterone -> female external genitaliaAdd testosterone?25Put it all together.A normal genetic female receives injections oftestosterone throughout fetal development. She is bornwith will be born with: ovaries. male internal reproductive ducts. undeveloped female reproductive ducts. male external reproductive organs. all of the above

26PubertySecondary sexual characteristicsDevelop during pubertyDistinguish males and femalesNot directly involved in reproductionFor exampleFacial hair, deep voice, breastsHormonal changesAnterior pituitary -> growth hormoneAnterior pituitary -> gonadotropic and adrenocorticotropic hormones -> maturation of genitals

27Goal reviewYou should now be able toExplain how sexual differentiation occurs GonadsInternal reproductive ductsExternal reproductive organsDescribe the hormonal changes that occur during puberty and the effect they have on the body

28Sample test questionSry protein triggers the development of:the testes. a Mllerian system. the penis. ovaries. 29Sexual differentiation of the brain30Male vs. female brains

31Think about itDefend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.

1:0032Think about itDefend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.

:3033Activity 3Defend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.Prepare at least two arguments in support of your decision (i.e. two reasons why you chose to defend/refute this statement)

3:0034Activity 3Defend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.Prepare at least two arguments in support of your decision (i.e. two reasons why you chose to defend/refute this statement)

2:0035Activity 3Defend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.Prepare at least two arguments in support of your decision (i.e. two reasons why you chose to defend/refute this statement)

1:0036Activity 3Defend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.Prepare at least two arguments in support of your decision (i.e. two reasons why you chose to defend/refute this statement)

:3037Activity 3Defend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.DefendRefutePrepare at least two arguments in support of your decision (i.e. two reasons why you chose to defend/refute this statement)

Times up!

38Activity 3 - RecapDefend/refute: The differences between the male andfemale brains in humans are explained by the presenceor absence of testosterone during development.DefendRefutePresence/absence of testosterone plays a role, but it is far from the whole story39Activity 3 - RecapMales have higher levels of androgens, including testosterone (T)Does T act directly on brain to cause changes?No

40Activity 3 - RecapAromatization hypothesis proposes that:T is converted into estradiol (aromatization)Causes masculinizationEvidence for aromatization theoryEarly estradiol injections -> masculinize brainIf T present, but aromatization blocked -> no masculinization of brain

41Activity 3 - RecapBUT..Most of this research was focused on the hypothalamus..of rats!Why?

42Activity 3 - RecapAromatization hypothesis is not sufficientMuch more complicatedAromatization only critical in certain brain areasSubstantial variation between speciesVariation in different developmental periods within speciesSex chromosomes exhibit unique, independent effectsEstradiol also plays an active role43Activity 3 - RecapTake home messageAromatization hypothesis is not sufficientMuch more complicatedCause of differentiation varies based on part of brain, species and stage of developmentPresence/absence of androgens is not the only important factor44Hormones and behaviorHow do hormones affect behavior?Most of this research is on rodentsStudy reproductive behaviorT in females - masculinizes and defeminizes sexual behaviorNo T in males demasculinizes and feminizes sexual behaviorMuch more complicated in humans

45Masculinization and feminizationTwo separate dimensionsNOT oppositesMasculine behaviorMale typical behaviorsFeminine behaviorFemale typical behaviorsCan have both at once or neither

46Goal reviewYou should now be able toExplain the aromatization hypothesisSummarize what we understand about sexual differentiation in the mammalian brain, includingAromatization hypothesis and humansKey findings in the area

47Sample test questionThe aromatization hypothesis states that:Testosterone is directly responsible for masculinizing the brainMale and female brains are not differentiated (i.e. thereare no sex difference in brain development)estradiol created in the brains of developing males from circulating testosterone masculinizes their brains. estradiol created in the brains of developing females from circulating testosterone feminizes their brains.

48In class assignment 449Male vs. female?INDIVIDUAL ICA Each person should turn in their own answer (make sure to put your name on it!)Consider what youve learned in your reading (including the three case studies at the end of your reading for today pp. 340 342) and in lecture todayHow has this influenced your opinion of what makes us male or female? Do you think male and female are two distinct separate categories? Why or why not?There is no correct answer, but make sure to support your opinion with a well-reasoned argument based on class materialPut in team folder or bring to front of class.50