Exam 4- Male Reproductive Physiology I Flashcards
from what do sertoli cells originate?
pluripotent coelomic epithelial cells of the gonadal ridge
what do sperm originate from?
spermatogonia
what do leydig cells originate from?
mesenchyme of gonadal ridge
what do leydig/interstitial cells produce?
testosterone
what do sertoli/sustentacular cells produce?
anti-mullerian hormone (AMH)/mullerian inhibiting substance (MIS)
inhibin
estrogen
androgen-binding protein (ABP)
what gonadotropins/hormones does the hypothalamus produce?
GnRH
LH and FSH
prolactin
oxytocin
vasopressin
estrogen from testosterone via aromatase
what areas of the brain are involved in reproduction?
pituitary/hypothalamus
what is the tonic center of the hypothalamus?
important in male
small frequent surges of GnRH from hypothalamus induce LH which stimulates production testosterone
what is the surge center of the hypothalamus?
important in female
high amplitude surge GnRH leads to large surge LH which leads to ovulation
what is puberty?
age at which majority of males in given breed/species/population exhibit sufficient size and libido and produce adequate sperm to produce pregnancies
how does testosterone defeminize the hypothalamus?
fetal testes produce
aromatase converts to estradiol
estradiol eliminates surge center
alpha-fetoprotein binds estradiol (gonadal) to prevent from crossing blood-brain barrier
what binds to estradiol and prevents it from crossing the blood-brain barrier?
alpha-fetoprotein
what does androgen binding protein do?
binds to testosterone
increases concentration testosterone in seminiferous tubules which is necessary for spermatogenesis to occur
what are the factors that lead to puberty?
metabolic: major
environmental/social cues
genetics/breed
how is puberty inhibited?
GnRH neurons
tonic center only
decreased sensitivity as puberty approaches
what increases at puberty?
testosterone
GnRH secretion
why do accessory sex glands and cells related to secondary sexual development have testosterone receptors?
have 5-alpha reductase in cells
converts testosterone to dihydrotestosterone (DHT): very potent
both males and females
what are the accessory sex glands that develop due to increased testosterone?
ampulla
prostate: body/disseminate parts
vesicular gland
bulbourethral gland
what two hormones’ secretion patterns change at puberty?
GnRH and LH
how long is the complete cycle of seminiferous epithelium?
60 days
what do sertoli cells secrete to control spermatogenesis?
inhibin
estradiol
AMH/MIS
what do leydig cells secrete to control spermatogenesis?
testosterone
what receptors do leydig cells have?
LH receptors
what stimulates the anterior pituitary to release FSH?
GnRH from tonic center
why is it necessary to have episodic testosterone levels in the testes?
would have: metabolic overload
sustained negative feedback on GnRH neurons (reduced LR and testosterone)
sustained negative feedback on FSH
what produces androgen-binding protein?
sertoli cells
what is needed in the seminiferous tubules to support spermatogenesis?
high concentration testosterone
what are the three components of immune privilege?
anatomical
physiological
immunological
what is the immunological component of the immune privilege of the testes?
blood-testis barrier
immune cells within interstitial space
what can produce antibodies against sperm and where are the antibodies found?
accessory sex glands
seminal fluid
what develops without estradiol in the brain?
surge center
what produces alpha-fetoprotein?
fetal liver
how do GnRH neurons inhibit puberty?
have increased sensitivity to negative feedback of testosterone
how does luteinizing hormone impact testosterone?
increases its secretion from leydig/interstitial cells in testes
what are the substances that interfere with GnRH/LH?
GnRH vaccine
LHRH agaonists
LHRH antagonists
what is involved in developing secondary sex characteristics?
dihydrotestosterone
why is luteinizing hormone not secreted for hours, instead of minutes?
would result in:
metabolic overload
sustained negative feedback on GNRH neurons in hypothalamus (reduced LH and testosterone secretion)
sustained negative feedback on FSH
what are the components of the physiological component of immune privilege in the testes?
specialized transport systems
testosterone is immunosuppression within interstitial space
what converts testosterone to dihydrotestosterone?
5-alpha reductase
