Male Reproductive Physiology Flashcards
Gonadotropin secretion over the lifetime
when is FSH>LH
Review of male hypogonadism
Hypothalamic pituitary gonadal axis male
Hypothalamus secretes GnRH that stimulates the AP. Ap releases LH and FSH. LH receptors on Leydigs, so stimulates them, mediating production of test and other androgens,
testosterone can cross over to the sertoli cells and stimulate them because they have test receptors as well as being stimulated by FSH . products of this are production of abp, estrogen through synthesis of aromatase, mediating the process of spermatogenesis. the other product is inhibin TYPE B. feeds back onto ap negatively for FSH.
the aspect of regenerating estrogen or DHT, influence negatively at AP and the Hypo
Fetal actions of Test
- when does test present?
- causes what during the last 2-3 motnhs of pregnancy?
- whats it called if this fails
phases of Spermatogenesis:
Mitotic divisions (spermatocytogenesis) starts at puberty and mitotic cycles increase and spermatogonia or stem cells divide to produce daughter spermatogonia, resulting in Primary spermatocytes
Meiosis: primary spermatocytes undergo two divisions. first divsion produces to secondary spermatocytes each w/ a haploid DNA, second division produces two spermatids, each with a haploid # unduplicated
Spermiogenesis: spermatids mature into spermatozoa, ends w/ release of spermatozoa by sertolis
Specific actions of DHT:
- fetal differentiaion of ehat?
- hair?
- sebaceous gland?
- prostate?
- 5a reductase inhibitors
Which enzyme converts T to DHT in peripheral tissue
5a-reductase
Synthesis and secretion of T mechanism
Gonadal sex vs phenotypic sex
Feedback regulation of spermatogenesis in normal male vs male receiving exogenous Test
Focus on normal set point is being changed by adding more T to circulation. leads to low levels of LH and fsh but more so LH because LH is more sensitive to levels of androgens. repress hypothalmic and pituitary secretion low levels of LH. Leydig cells produce less Testosterone,which is important for spermatogenesis. impact in fertility of this individual.
DHT role in puberty
DHT binds to androgen receptors w/ greater affinity, deficiency of 5a reductase results in ambiguous external genitalia
Biosynthetic pathway of androgens in male:
- mitochondrial enzymes do what?
- what is the rate limiting step?
Where are the spermatogonia located?
- where are the spermatozoa located?
- percentage seminiferous tubules vs interstitium
Male Hypogonadism: Klinefelter
- dysgenesis of what?
- most common karyotype?
- what production is low, and levels of what are high?
= what degree of hypogonadism?
Capacitation of spermatozoa:
- what happens when they contact female fluid?
- what are the changes in the uterine tubes, cholesterol, Ca+2
Seminal vesicles:
produce what?
purpose?
purpose of prostaglandins? how does it work?
Different stages of male sexual function: plasma T and sperm production
Function of sertoli cells:
provide nutrients to differentiating sperm, form tight junctions with each other creating a barrier between testes and bloodstream, secrete an aqueous fluid into the lumen of the seminferous tubule to help transport sperm through the tubules into the epi
Secretions of vas def, seminal vesicles, and prostate gland
vas def secretes fluid rich in citrate and fructose, seminal vesicles secrete fluid rich in citrate, fructose, prostaglandins and fibrinogen.
-prostate secretes milky aqueous solution rich in citrate, calcium, and enzymes
Andropause:
- as men age what happens to sensitivity to LH? leading to?
- what happens to serum LH/FSH?
- what happens to test levels
- loss of sexual activity
Estrogen production in males
- which fluid is it highest in?
- what is the small and big source of estrogen
- potential role in spermatogenesis?
Emission:
- under what innervation?
- what prevents retrograde ejac of semen into bladder?
- is emission same as ejac?