Lecture 25 - Testes Flashcards
The androgenic effect of testosterone occurs when it diffuses into the _____ cells where it will be bound to androgen binding protein and also converted to DHT –> DHT diffuses into _____ _____ fluid to promote spermatogenesis.
Sertoli cells
Seminiferous tubule
Only 2% of testosterone is free in circulation, 45-65% is bound to ______, the rest is bound to albumin.
SHBG (sex hormone binding globulin)
Sertoli cells secrete _____ or _____ which promotes the involution of the Mullerian ducts.
AMH (anti-mullerian hormone) or MIF (Mullerian Inhibitory Factor)
By the 8th week of fetal development, _____ cells begin to appear and secrete testosterone, which helps promote the maturation of the Wolffian ducts –> which develop into the ______, _____ _____, and ______ _____.
_____, formed from Testosterone, is responsible for development of the ______ sinus and external male _______.
Leydig
Epididymis, Vas Deferens, and Seminiferous Vesicles.
DHT
Urogenital sinus
Genitalia
Just like the action of ACTH in adrenal cortical cells, _____ acts on Leydig cells to increase the concentration of free _______ and its conversion to Pregnenolone.
LH
Cholesterol
_____ is the hormone produced by Sertoli cells in response to FSH, and it acts via negative feedback on the AP –> decreases FSH.
Inhibin
Sperm can last up to ____ weeks in the tail of the epididymis and vas deferens.
5 weeks
Vasodilation during erection is as follows:
NO –> Soluble ____ cyclase –> increased _____ –> vasodilation.
Soluble guanylyl cyclase –> increased cGMP –> vasodilation
_______ is the enzyme that degrade cGMP, and _____ is a medication that blocks this degradation –> promotes erection.
Phosphodiesterase
Sildenafil (Viagra)
Congenital 5alpha-reductase deficiency results in lack of conversion of testosterone to _____ –> ambiguous genitalia at birth.
Congenital AR deficiency results in _____ (male or female?) phenotype despite presence of androgens.
DHT
Female
