Ch. 11 The Physiology of Sex Differences Flashcards
Week 3 (31 cards)
What are the classes of steroid hormones?
3 major classes of steroid hormones produced by the adrenal glands: glucocorticoids, mineralcorticoids, and androgens. 3 types of androgens produced by the gonads: estrogens, progesterones, and testosterone. T is responsible for the differentiation of male sex organs, and E and P are responsible for coordinating the menstrual cycle in females.
What is the typical exposure to T for boys?
begins in prenatal weeks 8-24 when the testes first develop, with a second surge occurring 2 wks after birth until they are 4 mths old.
How do internal sex organs develop?
all fetuses have the potential of being M or F regardless of genetic makeup bc they all have the Mullerian and Wolffian tracts to develop M or F int reproductive organs. the SRY gene of the Y chromo is responsible for the bi-potential gonads developing into testes. then sertoli cells in the testes secrete anti-mullerian hormone and get mullerian tract regress. after sertoli cells activate leydig cells to produce T which stimulates the devel of the wolffian tract. if no anti-mullerian hormone hormone is secreted during that initial critical period, than the wolffian tract will regress and the mullerian tract will become the F int organs. its thought that proteins such as FOXL2 or FIGX might work to repress M sex organs transcription factors
How do external sex organs develop?
all fetuses also have a common undifferentiated embryonic structure that develops into either M or F ext genitalia. DHT is responsible for this developing into the prostate, penis, and scrotum in M fetuses.
What does the brains early exposure to T do?
impacts behaviours that are associated with the hypothalamus and preoptic areas which are often found to be larger in Ms. studies in rodents show that early exposure to T during the critical phase will lead to the masculinization of these structures regardless of ones genetic sex, which then affects behaviours related to ones sexual preference. aggressive play behaviour may also be a behaviour thats coded for due to the release of T during the critical period
How does T affect AIS?
we know that XY ppl who have androgen insensitivity are unresponsive or partially unresponsive to T, which can disrupt or potentially halt the masculinization process. if the form of the AIS is complete the person will lack body hair and will present and ID as F. this suggests that gender ID and sexual orientation are likely affected by this process.
How does T exposure in early life affect behaviour and skills?
measurable effects on the two and can influence spatial skills in adulthood. While many of these factors are also influenced by social expectations, cultural gender norms and stereotyping, research on animals have shown similar discrepancies in play styles between females and males of that species. In humans, the only skills to demonstrate robust “sex differences” are those related to spatial skills, where male members of most species tend to show enhanced navigational skills that use directional coordinates or visualization over female members, while women tend to be better at navigating through using landmarks. This might reflect some small, innate sex differences on spatial perception, that result from early testosterone exposure (or lack of exposure) during development.
What are organizational effects?
effects that steroid hormones have on the developing organism in the prenatal and perinatal period.
What are activational effects?
effects that steroid hormones have on postpubertal adults.
What are steroid hormones?
a class of hormones that derive from cholesterol and produced primarily by adrenal glands and gonads.
What is the SRY gene?
critically involved with genital and testicular development.
What is the Mullerian tract?
develops into the F int reproductive organs and is present in the embryo.
What is the Wolffian tract?
develops into the M int reproductive organs and is present in the embryo.
What are Sertoli cells?
in M gonads, at 6 wks of embryonic devel, will secrete anti-mullerian hormone to induce the regression of the mullerian tract. complete by wks 8-9. also stimulate leydig cells.
What are leydig cells?
release T during the 12-17 wks of pregnancy to facilitate the devel of the wolffian tract. T released -> DHT and develops the prostate, penis, and scrotum.
What is the anti-mullerian hormone?
induces the regression of the mullerian tract.
What is sexual dimorphism?
sex differences btwn individuals of the same species.
What is the aromatization hypoth?
T is converted to E and DHT by the enzyme aromatase. these metabolites and their activity at estrogen receptors is what produces the observed effects of masculinization in the brain.
What is Turners syndrome?
an X-linked DSDm ppl with TS wither completely lack a 2nd chromo, or the 2nd chromo is either severely malformed or expressed inconsistently throughout the body. ppl with TS present as F but usu their gonads are undifferentiated.
What is a navigational strategy?
how men and women navigate around them. via landmark based directions or Euclidean based directions.
What are landmark-base directions?
women are better at recalling landmarks and landmark based directions when navigating
What are Euclidean based idrections?
men are better at navigating when given geometrical cues.
What is perceptual speed?
rapidly selecting and identifying items.
What is andropause?
androgens reaching low enough lvls in males as they age. symptoms; sexual dysfxn and loss of bone. mass.
