Lect 2: Male Repro Flashcards Preview

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Flashcards in Lect 2: Male Repro Deck (11)
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Full development and function of the seminiferous tubules require

androgens and FSH


In human males testosterone is produced mainly by

Leydig cells


Nitrous oxide synthase contributes to erection by

activating soluble guanylate cyclases to increase cGMP levels that relax smooth muscle and increase blood flow


Testosterone is produced

in Leydig cells from cholesterol and pregnenalone precursors


The pubertal growth spurt is stimulated by the hormone



The hormone inhibin has direct negative feedback effects on the release of



a 16 y/o girl suffers from 5alpha-reductase deficiency. The individual was raised as a male but at puberty secondary sex characteristics and male growth occurred. Levels of which steroid is reduced during puberty?



A 55 y/o man complains of reduced libido and muscle strength. Serum analysis showed reduced levels of testosterone. Reduced activity in which hormone--target axis is causing the symptoms?

Leuteinizing hormone (LH)--Leydig cell


In order for male differentiation to occur during development testosterone must be secreted from the testes. WHich hormone stimulates the secretion of testosterone?


Human chorionic gonadotropin also binds to luteinizing hormone receptors on the interstitial cells of the testes of the male fetus, resulting in the production of testosterone in male fetuses up to the time of birth. This small secretion or testosterone is what causes the fetus to develop male sex organs instead of female sex organs.


A man is taking lots of med, one of which is interfering with the emission phase of sex. Which med is causing this?

inhibitor of sympathetic nervous system receptor


Emission is elicited by reflexes mediated by the sympathetic nervous system. Beta adrenergic antagonists interfere with the reflex. None of the other choices is involved.


Men who take large doses of testosterone-like androgenic steroids are sterile in the reproductive sense of the word. Why?

High levels of androgen compounds inhibit the secretion of gonadotropin-releasing hormone by the hypothalamus, resulting in the inhibition of luteinizing hormone and follicle-stimulating hormone release by the anterior pituitary.

Testosterone secreted by the testes in response to luteinizing hormone (LH) inhibits hypothalamic secretion of gonadotropin-releasing hormone (GnRH), thereby inhibiting anterior pituitary secretion of LH and follicle-stimulating hormone. Taking large doses of testosterone-like steroids also suppresses the secretion of GnRH and the pituitary gonadotropic hormones, resulting in sterility