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90 Cards in this Set
- Front
- Back
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What is the SRY?
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this is the sex determining region of the Y
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What does SRY make?
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this makes testis determining factor, which promotes testis differentiation
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What does the XO genotype result in?
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this results in ovarian dysgenesis- as two X's are needed for functional ovary development
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What do Setoli cells secrete during testicular development? what does it do?
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Antimullerian hormone. this causes mullerian duct regression.
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What does Leydig cells secrete during testicular development? what does it do?
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this secretes testosterone.
leads to development of wolffian duct. (the testosterone produced becomes DHT (the active form) by 5a-reductase)) |
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What is the default development pathway?
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female differentiation (mullerian duct predominates)
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What does the mullerian duct become?
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internal female genitals
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what does the wolffian duct become?
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internal male gentials
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where are most androgens found?
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bound to proteins, like albumin. but MOST are bound by sex hormone binding globulin
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what cells make androgen binding protein?
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sertoli cells
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What are the two metabolites that have biological activity?
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DHT and estradiol
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What is the enzyme to produce estradiol?
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Aromatase (converts testo)
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What is the enzyme to produce DHT?
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5 alpha reductase (converts testo)
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What is the rate limiting step of ALL steriodogeneis synthesis?
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20,22 desmolase...
Cholesterol-> Pregnenolone. |
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are steroids stored?
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NO- made on demand
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What does 3 Beta Hydroxsteriod dehydrogenase do?
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this converts Pregnenolone-> progesterone
(important in females)- just like in the adrenal pathways. |
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What is the most potent androgen?
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DHT
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What does 17B hydroxysteroid dehydrogenase do?
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this converts Androstenedione into testosterone
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Where is most testosterone made?
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in the testes
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where is most DHT made?
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in the cells its required (peripheral)
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What is the most prevalent androgen?
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DHEA-S
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What do androgen receptors bind to while they wait for androgens to show up?
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heat shock proteins, these help hold them conformationally stable
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What turns testosterone into DHT?
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5 alpha reductase
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What turns testosterone into estradiol?
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aromatase
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What is broken in androgen insensitivity syndrome?
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the androgen receptor cannot get the signal from the leydig cells
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what are the external gentials in androgen insensitivity syndrome like?
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female!
testo is made, 5alpha reductase works, DHT is made, but DHT cannot act to turn the external genitals male. |
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Is AMH secretion present in androgen insensitivity syndrome?
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yes! degrades the mullerian duct, so no female internal gentials
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when does androgen insensititivity syndrome usually get diagnosed?
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pubertiy, due to amenorrhea
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What is the problem in Pseudohermaphroditism?
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congential adrenal hyperplasia.
no 21-hydroxylase, no cortisol production (but aldosterone production)-> causes excess androgen production |
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What is the geneotype in Pseudohermaphroditism
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XX
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what is the internal genetalia in Pseudohermaphroditism?
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female, wolffian duct regresses
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what is the external gentalia in Pseudohermaphroditism
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female, but super enlarged, can appear female
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how would an XY person who lacks the SRY gene develop?
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they would be female internal and externally.
chromosomal sex determines everything else, no SRY, no male |
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how would an XY person who has 5alpha reductase deficiency develop?
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male internal, female external.
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What happens in 5 alpha reductase deficiency?
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female until puberty, the the testosterone levels get so high, that male sex organs develop
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Where does spermatotgenesis take place?
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in the seminiferous tubules
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What do sertoli cells do?
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these hold on to the spermatogonia during their development "mother cells" - also make AMH
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How is GNRH released? from where?
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released in PULSES every 2-3 hours. from hypothalamus
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What happens in constant GNRH?
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this downregulates the GNRH receptor....
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What do gonadatrop cells produce? where are they located? and what do they respond to?
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LH and FSH
these are in the anterior pituitary respond to GnRH |
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What does FSH do?
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this activates sertoli cells to activate spermatogenesis.
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What do setoli cells make in response to FSH?
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adrogen binding protein, and aromatase.
important for high local testosterone production Inhibit (which feeds back pituitary and shuts down FSH) |
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what does inhibit do?
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this inhibits FSH
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What does LH do?
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binds leydig cells, and promotes testoserone via 20,22 desmolase
cholesterol -> pregnenelone. RATE limiting step |
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What is the second messenger system for LH and FSH?
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Gs-> AC-> cAMP-> PKA
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What hormones are necessary for spermatogenesis to occur?
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FSH and Testosterone and LH
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What is spermatogenesis?
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the is the whole process, from spermatogonia to spermatoza
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What is spermatocytogenesis?
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this is from spermatagonial mitosis to spermatides
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what is spermiogenesis?
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packing of spermatids to spermatozoa (changes for mature sperm)
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what is spermiation?
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extrusion of sperm into tubule lumen
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how long does spermatogenesis take?
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60-70 days
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How does production in the seminiferous tubule occur?
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in a wave, the spermatogenic wave
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What hormones is spermatogenesis dependent on?
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both testosterone and FSH
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What are the 3 major stages of spermatogenesis?
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Mitotic proliferation
Meiosis Packaging |
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What is the germline stem cell for males?
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the spermatogonium.
this produces 2 daughter cells, one replaces the original, and the other undergoes mitosis to produce sperm. |
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What is the N and type of primary spermatocytes?
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4N and diploid (4n during mieosis duplication)
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What is the N and type of secondary spermatocytes
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Haploid and 2N
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What happens in the packaging of spermatozoa?
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loss of cytoplasm and development of flagella
condensed chromatin, (due to protamine replacing histones) formaiton of acrosome |
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What hormone promotes the packaging of spermatozoa?
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Testosterone dependent.
requires high testo, aided by sertoli (mother cells) making ABP (androgen binding protein) due to FSH |
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why is it important for the primary spermatocyte to cross the tight junctions?
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the cells are becoming unique, and can cause immune responses (due to protamines)
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What is it called when spermatozoa are released into the seminiferous lumen?
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spermiation
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after spermiation, where do sperm cells do more maturation?
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in the epididymis
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What produces fluid for the efferent ducts?
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sertoli cells
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What does testosterone do to the efferent ducts and epididymis?
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this promotes contraction of SM and movement of fluid/sperm
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why is temp of the testes so important?
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high temps produce low sperm counts
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How does LH promote spermatogenesis?
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LH activates 20,22 desmolase, the rate limiting step in testo production.
in the leydig cells testo promotes spermatogenesis. |
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How does FSH promotoe spermatogenesis?
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FSH binds the sertoli cells, and promotes ABP production, increasing testosterones concentration
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What happens to a man with mutant ABP?
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they would be infertile, due to no super high testosterone gradient.
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How long does sperm hang around in the epididymus?
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about 2 weeks
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What happens in the epididymus?
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sperm maturation, sperm concentration.
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What do the vas deferens do?
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store sperm
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What happens when mechanoreceptors of the penis are stimulated?
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inhibition of sympathetics, and parasympathetics are stimulated.
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Where does direct parasympathetic innervation of arterioles take place?
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in the erectile tissue, and in your brain
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What does Viagra do?
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this blocks phosphodiesterase from degrading cGMP.
NO-> guanylate cyclase-> cGMP-> relax SM |
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What happens in the Emission phase?
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there is Sympathetic stimulation, causes contraction of SM and dumps into the urethra
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What happens in the expulsion phase?
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sympathetic nerve impules due to urethra being filled. activate skeletal muscles to expel sperm
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what is the definition of sterility?
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less than 20 million sperm/ ml
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What is the key factor that determines sperm cell count?
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Sertoli cells
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What does the seminal vesicle do?
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this dilutes the sperm
fluid includes ascorbic acid, PG's, fibrinogen, fructose. |
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Where does the seminal vesicle empty into?
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the ampulla
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what does the prostate secrete?
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milky, alkaline fluid- wiht PO4
citic acid, acid phosphatase, clotting enzymes. |
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what does the bulbourethral gland do?
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this secretes a mucus secretion prior to ejaculation.
for lubircation. |
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What does prolactin do in males?
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this stimulates androgen receptors in all accessory gland, and thus it helps maintain them
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What does the prostate grow best to?
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this grows best with DHT
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When does capacittion occur?
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while the sperm swims through the female reproductive duct
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What happens during capacitation?
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cholesterol withdrawal
changes in surface proteins calcium influx- Causes WHIPLASHING |
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What two proteins trigger the acrosome reaction?
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ZP2 and ZP3
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What happens in the acrosome reaction?
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pores in sperm membrane formed
calcium dependent exocytotic event. enzymes released degrade ECM |
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How does testosterone regulate gonadotropin release?
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testo has a negative feed back on GnRH and LH and FSH
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What happens in major testo exogenous administration?
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huge drops in FSH and LH.
will become hypogonadal, sertoli cells shut down due to low FSH and LH |
