Phys DSA (montemayor) - SRS Flashcards
(46 cards)
What is another name for klinefelter syndrome?
•XXY Seminiferous Tubule Dysgenesis
What promotes the intrauterine development of the testes?
SRY gene produces TDF (testes determining factor)
What cells produce antimullerian hormone?
Sertoli cells
What hormone action is needed for the wolfian duct to develop?
Testosterone
What are the wolfian duct structures?
seminal vesicles
ejaculatory duct
vas deferens
epididymus
Which cells in the testes produce testosterone?
Leydig cells
What hormone stimulates fetal leydig cell production of testosterone during development prior to fetal pit. LH?
HCG
•What is required for the development of the penis, scrotum and prostate?
–DHT (Dihydrotestosterone)
•What enzyme is required for the conversion of testosterone à DHT?
–5α-reductase-2
–5α-reductase-1 is more expressed in skin, so in what condition might this come into play?
Acne treatment
Which binds tighter to their shared receptor, DHT or testosterone?
DHT
5α-reductase-2 deficiencies lead to what phenotypical changes?
ambiguous or feminized external genitalia
What goes down at 6-8 weeks gestation in the male differentiation
Differentiation of testes
[SRY transcription factor]
What happens in weeks 8-9 of male gestational development (UG tract)
- Retention of wolffian ducts
- [Testosterone]
- Regression of müllerian ducts
- [Antimϋllerian hormone]
What happens in weeks 9-13 of male genital development?
Male-type external genitalia
[DHT]
In klinefelters, why the gynecomastia?
–Elevated estradiol levels and increased estradiol-to-testosterone ratio
–Peripheral conversion of testosterone à estradiol
•Which enzyme converts androgen to estrogen?
–CYP19-aromatase
•What hormone is considered to be responsible for the normal initiation of puberty?
–Resurgence of pulsatile sleep-associated GnRH secretion from the hypothalamus during adolescence, along with increased gonadotrope sensitivity to GnRH.
In this patient with Klinefelter Syndrome, increased levels of gonadotropins failed to induce normal testicular growth and spermatogenesis.
What happpens to the testes?
Seminiferous tubules?
- The testis became fibrotic and hyalinized and remain small and firm.
- The seminiferous tubules are largely destroyed and he is infertile.
What hormones are affected and how in primary hypogonadism?
–Gonadotropin levels are elevated
–Androgen production is reduced
What hormone is the key player in development of secondary sex characteristics, such as penis size, bear development, etc?
DHT
What percent of testosterone circulates as….
–SHBG (sex hormone-binding globulin) bound:
–Serum albumin bound:
–Free:
–SHBG (sex hormone-binding globulin) bound: 45-60%
–Serum albumin bound: 38-55%
–Free: 2-5%
•Which cells are the primary site for the production of testosterone in males?
LEydig cells
•What protein is responsible for maintaining testosterone concentration in the testes?
–ABP (androgen-binding protein)