Reproductive Lecture 1 Flashcards
What is the most important part of the Y chromosome?
SRY (sex determining region)
contains Testis Determining Factor (TDF)
XY mice w/o SRY develop _______
ovaries
XX mice with SRY develop _________
testis
Loss of 1 X chromosome from female results in _________________________________
ovarian dysgenesis but not loss of female ducts/genitalia
Do meiosis I and II result in haploid daughters?
yes
True or false: male meiosis is continuous process while female is punctuated
true
Where does oogenesis arrest before puberty?
substate of prophase of meiosis I (diplotene stage)
When does meiosis complete?
upon fertilization
Spermatogenesis develops how many daughter cells per germ cell? What about oogenesis?
Spermatogenesis: 4
Oogenesis: 1 (plue polar bodies)
how do oogonia replicate in the ovary?
Mitosis
what is atresia?
lots of eggs/oogonia thrown away (occurs right before birth)
How many eggs do women have at birth?
2.5 million
How many sperm are produced per day?
200 million
When does spermatogenesis begin?
puberty
What are 4 problems that can lead to defects in genetic sex?
1) Aneuploidy (change in # of chromosomes)
2) Mosaicism (different genotypes in different cells)
3) Chimerism (different zygotes that fuse)
4) Structural Errors (recombination)
Is gondal development hormone dependent?
NO (gonads produce the hormones, it can’t be)
Sertoli cells are like ____________ cells in the female
granulosa
What do sertoli cells produce?
anti mullerian hormone
Leydig cells are like _____________ cells in the female
Theca
What do Leydig cells produce?
testosterone
What do the germ cells go on to become?
spermatogonia or oogonia
What direct the specific development of gonads?
germ cells
Development of the _________ (XY): seminiferous tubules, spermatogonia, sertoli cells, leydig cells
medulla
Development of the _________ (XX): secondary sex cords, oogonia, theca cells, granulosa cells
cortex
Are there exclusive female or male hormones?
NO, both sexes have similar hormones and receptors – dimorphism is due to differences in amounts of individual hormones
What two hormones are necessary for male genital duct development?
1) testosterone (keep wolffian ducts)
2) AMH (degrade mullerian ducts)
True or false: take out ovaries and testes and you still get mullerian ducts
TRUE
What do the wolffian ducts become?
epididymis, vas deferens, seminal vesicles, ejaculatory duct
What 2 functions does AMH have?
1) causes mullerian duct atrophy
2) coordinates development and stimulate of Leydig cells
What do mullerian ducts develop into?
fallopian tubes, cervix, upper vagina
Do female structures require estrogen to develop?
NO but they do require it to achieve normal size
If TDF doesnt direct testicular development before 9 weeks, what happens?
an ovary develops
What enzyme converts testosterone to DHT?
5a reductase
What is responsible for male genitalia development?
DHT (via androgen receptors)
What blocks 5a reductase?
Finesteride
Define Klinefelter’s
XXY
seminiferous tubule dysgenesis (have wolffian duct and regressed mullerian)
low testosterone because Leydig cells are hit hard by stimulatory pathways (LH) and estradiol starts getting produced
What is Turner’s syndrome?
XO (streak genitalia, never developed ovaries)
Define male pseudohermaphroditism
have female external genitalia but testes
What is AIS? (androgen insensitivity)
XY but no receptor for androgen so external genitalia is female (have testes which are making hormones but no way to process it)
What testicular cells are stimulated by LH?
Leydig (L–>L)
What testicular cells are stimulated by FSH?
Sertoli
Which cells secrete inhibin?
Sertoli
What effect does testosterone have on the hypothalamus and pituitary?
inhibits it
What enzyme makes estradiol?
aromatase
What does LH do in controlling testosterone production?
controls rate-limiting reaction (cholesterol to pregnenolone)
Describe how testosterone travels through the blood?
45% bound to SHBG
55% bound to albumin and CBG
2% free
