Week 3 Flashcards by Sara Richmond

________ the theory that all sex information is determined by chromosomal information then the gonads are responsible for further differentiation in life

central dogma

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_________ occurs in alligators and turtles. Temperature of egg determines gonadal sex

environmental sex determination

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In alligators

high temperature is more females. Reverse in turtles

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______________
Mammals: XX and XY
Birds: ZZ male and ZW female
Fruit flies: XX female and XY male

genetic sex differentiations

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________ is mamalian determining number of X chromosomes is irrelevant

mammalian Y chromosome

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The local on the Y chromosome ___________ is the testis determining factor of the Y chromosome

TDY

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The gene in the TDY locus involved in testes development is the ________

SRY genes

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deletion of the SRY gene. results in

XY gonadal females

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Sryexpressed in undifferentiated gonadal ridge

•Sryinduces differentiation of _________, the first testicular cells!!

Sertoli cells

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•Sryincreases expression of ________an ancient testis differentiation gene, causes cascade of events to commit gonad to testicular fate

Sox9,

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__________ develops in absence of Sry, no matter what the sex chromosome complement (XX or XY)

•Ovary

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Males have all of the genes to make an _________

* Females have all the genes to make a ________ except ____________

ovary.

testis, except Sry (and a few Y genes needed for spermatogenesis).

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SEX in BIRDS

Birds
ZZ male (testes)
ZW female (ovary)
Female has a small W
chromosome lacking in male
(like male mammal’s Y)

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SEX in FLYS

•Presence of Y chromosome is irrelevant to maleness
•X:A ratio is sex determining, if 1 then female (2X or more), if <1 (1X)
then male.

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what is the 20th century dogma

genetics determines the sex of the gonads

- sex differences are determined by hormones

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_________ becomes oviduct, uterus, upper vagina

mullein duct

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__________ becomes a efferent duct, ducts deferens, epididymus, and associated glands

wolfian duct

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Genetics and the appropriate hormones cause the appropriate duct system to develop and the _______________

opposite to degenerate

___________ secrete Müllerian Inhibiting Hormone, causes involution of female ducts (oviducts, uterus, upper vagina)

Sertoli cells

__________ secrete testosterone which causes masculine differentiation (penis, scrotum, sperm ducts, brain, liver, physique)

•Leydig cell

•Hormone effects are __________

permanent and irreversible

a burst of _________ caused wolfing duct to develop

testosterone

Each sex’s phenotype emerges from a previously undifferentiated state
•Undifferentiated state is _________could go either way –some sex-specific force causes the sex difference, pushes the system in one direction

bi-potential,

Both sexes have same undifferentiated form

* Male (scrotum, penis) and female (vaginal labia, clitoris) derive from ________

same precursor

___________ internal genitalia are present in both sexes

•Male (Wolffian) and female (Müllerian)

Permenate: Gonadal hormone-induced

irreversible commitment of a tissue to a masculine phenotype.

Gonadal hormone-induced____________of a tissue to a masculine phenotype

irreversible commitment

What are the primary sex hormones

estradiol, testosterone, progesterone

______________ pathway is the conversion of cholesterol into testosterone and progesterone

stereogenic pathway

The male hormone (testosterone is the precursor to

estrogen

____________ estrogen synthase is an enzyme responsible for a key step in the biosynthesis of estrogens

aromatase

_________ converts testosterone to dihydrotestosterone which is vital for masculinization

5 alpha reductase

After gonadectomy and E2+P treatment of adult rats Females display ___________ Males____________

female reproductive behavior and have an LH surge\ | do not display female behavior nor have an LH surge

When females are treated with testosterone after birth. They perform less lordosis this is because

testosterone defemivnized behavior

When castrated males are injected with E and P what happens

They exhibited lordosis because testicular secretions are not present to defense behavior

Males deprived of testosterone (T) from the testes develop_______ •Females given testosterone around the time of birth exhibit __________ •Testosterone_________ sex behavior! •

female patterns of behavior; less female behavior; DEFEMINIZES

What about male sex behavior (i.e. mounting?) Males deprived of T neonatally do not _________ males, and females given T neonatally do __________ Testosterone _________ sex behavior!

mount like normal mount more than normal females. MASCULINIZES

rhesus monkey and psedohemaphrodites

Pseudohermaphroditesdaughters | of pregnant mothers treated with T

rhesus monkey and psedohemaphrodites

Pseudohermaphroditesdaughters of pregnant mothers treated with T These hemaphrodiets showed more male like behavior in terms of play and pursuit play

_______________ | Sex Difference in CNS male and female

Spinal Nucleus of the Bulbocavernosus (SNB)

_____________ control cupping or rat penis

medial bulbocavernosus and lateral bulbocavernosus

Males and females behave differently because of sex differences in their brains caused _______________ in a manner similar to external genitals and reproductive ducts.

by testicular secretions

1) Established by exposure to T during a critical perinatal period. 3) Blocked by perinatal exposure to an aromatase inhibitor. 4) Blocked by embryonic/postnatal exposure to ER blockers. 2) Masculine brain development is blocked by perinatal castration. Conclusion: C

reation of neural substrates that motivate masculineand NOT femininereproductive behaviors established in males by testicular T converted to E2 in brain and E2 binding to ER. (estrogen receptor) in POA (preoperative area)!

testicular T converted to E2 in brain and E2 binding to _________ in ________

ER. (estrogen receptor) in POA (preoperative area)!