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Reproductive System1
Duke PA Physiology
| Question | Answer |
|---|---|
| When are primordial germ cells in male and female generated? | embryogenesis |
| What are the chromosomal sex determinates? | XX and YY |
| What does expression of the gene SRY on chromosome Y result in? | testes (male) |
| What determines gonadal sex? | presence of testes vs ovaries |
| What is the source of hormone which determines external and internal genitalia? | gonad |
| What is phenotypic sex? | external and internal genitalia |
| What is necessary for maleness? | SRY |
| Is SRY sufficent for maleness? | NO |
| What in addition to SRY is necessary to have a phenotypic male? | genes on X chromosome that encode the testosterone receptor |
| When is male phenotype induced? | after 8 weeks of gestation |
| Sexual differentiation | the process by which specific gene products result in a gonad whose products make possible a male or female phenotype |
| female ducts | Mullerian ducts |
| male ducts | Wolferian ducts |
| What do Sertoli cells secrete? | Mullerian inhibitory hormone (MIF) |
| What does MIF cause? | regression of mullerian ducts in male |
| sexual identity | refers to whether indviduals consider themselves male or female |
| sexual preference | refers to whether individual is attracted to the same sex or the opposite sex |
| sexual functioning | refers to whether an individual has testes, ovaries, or gonads with both features |
| hermaphroditism | gonads with both features - retain Wolferian and Mullerian ducts |
| What responds to levels of circulating steroid hormones? | hypothalamus |
| What does GnRH regulate? | FSH and LH |
| What do FSH and LH do? | regulate the development and function of the gonads in male and female |
| What is GnRH secretion like in male? | continuous and pulsatile |
| What is GnRH secretion like in female? | cyclic (monthly pattern) |
| How sensitive is the hypothalamus in development? | super-sensitive |
| How sensitive is the hypothalamus in adult? | feedback |
| What does inhibin do? | inhibits FSH |
| Does inhibin occur in males or females? | both |
| what causes negative feedback of inhibin? | local secretion of testosterone |
| What is kespeptin? | clock that has to be turned on, allows hypothalamus to gain adult rhythms - absence of these genes products prevents puberty |
| Where are sperm made? | testes |
| Where do sperm go from the testes? | epididymis |
| Where do sperm go from the epididymis? | vas deferens |
| How much sperm is in typical ejaculate? | > 100 x 10⁶ sperm per 5 ml |
| What does the blood-testes barrier do? | prevents immune system from accessing developing sperm - protects stem cell population |
| What do the leydig cells produce? | testosterone and DHT |
| What do the sertoli cells produce? | various hormones |
| What coordinates the production of sperm? | hypothalamus |
| What is the length of the seminiferous tubules? | length of 3 football fields |
| What is the length of epididymis? | 6 feet |
| How many days does it take to go from a spermatogonium to a spermatozoon in the lumen? | 64 days |
| Can sperm swim when they are released from seminiferous tubules? | no - they are immobile |
| How long does it take for a sperm to be mobile? | 90 days |
| What does the epididymis do to the sperm? | further differentiate, help them become mobile |
| When do sperm become good swimmers? | in the ova duct - they learn how to swim then - they bury their heads in the ova duct epithelium, searching for an egg |
| What is the hormone control by sertoli cells? | testes-blood barrier, androgen binding protein, inhibin, convert testosterone to estradiol |
| What is 5 α reductase? | critical for making DHT |
| What is DHT? | dihydrotestosterone |