Sexual differentiation Flashcards
The bi-potential gonads are undifferentiated when?
The first five weeks of life
Maleness is determined by which gene?
SRY (Sex determining region of Y)
SRY is found on which part of the Y chromosome?
Short arm
In the presence of which transcription factor does the gonad differentiate into the testes at about week 6 of gestation?
TDF ( testes determining factor)
Seminiferous tubules are seen when?
8th to 9th week of gestation
When does the gonad differentiate into the testes?
About week 6 of gestation
The Mullerian Inhibiting Hormone (MIH) is produced by which cells?
Sertoli cells
The Mullerian Inhibiting Hormone (MIH) and Anti-mullerian hormone (AMH) are the same. T/F
T
What is the important function of MIH?
Causes the regression of mullerian (paramesonephric) duct ipsilaterally
Regression of the Mullerian duct occurs when?
7-8 weeks of gestation
Which cells produce testosterone?
Leydig cells
What stimulates testosterone production in the 8th to 10th week of gestation?
HCG
Testosterone is important in the development of which structure in males during the 8th to 10 weeks ofd gestation?
Wolffian ducts
Which substance causes regression of the mullerian duct?
MIH or AMH
Which structures originate from the Wolffian duct?
Epididymis, vas deferens, ejaculatory duct
Dihydrotestostserone (DHT) is a metabolite produced by enzyme 5-alpha reductace from which substance?
Testosterone
What is the effect of DHT in sexual differentiation?
It transforms the genital tubercle into the penis, and the urogenital sinus into the urethra and prostate gland
Which substance causes the development of Wolffian ducts?
Testosterone
In the first three months of life, stimulsation of gonadal steroidogensis is independent on fetal gonadotropins and depends on which hormone?
HCG
Which substances are involved in the desdent of the teste?
HCG and MIH/AMH
When does the testicles descend?
34-35th week of gestation
Which substance causes the genital tubercle to develop into the penis, and the urogenital sinus into the urethra and prostate gland?
DHT
Activation of both X chromosomes in the absence of TDF happens when?
9th week of gestation
What happens in the absence of MIF?
The paramesonephric duct develops into the uterus
When does the paramesonephric duct develop into the uterus?
9-20 weeks of gestation in the absence of MIH/AMH
The development of the paramesonephric duct into the uterus happens without the need for hormonal stimulation. T/F
T