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Flashcards in Reproductive Deck (23):

What is the reproductive system derived from?

Reproductive system is derived from the intermediate mesoderm, forms a urogenital ridge.


During which weeks are the primitive sex cords formed?

During weeks 5-6, the epithelium proliferates and penetrates the underlying mesoderm to form primitive sex cords.


In men, what do the primitive sex cords continue to develop into?

Under the influence of TDF, primitive sex cords continue to develop into medullary (testis) cords.


What do the medullary cords develop into at the hilum?

At the hilum, medullary cords develop into rete testis.


What is the connective tissue layer that develops around the testis?

The connective tissue layer that develops is the tunica albuginea.


What do the remaining medullary cords form?

The remaining medullary cords form the seminiferous tubules.


When does the gubernaculum shorten to pull testes towards the anterior abdominal wall?

The gubernaculum shortens pulling the testes towards the anterior abdominal wall during weeks 7-12. They arrive at internal inguinal ring, where they remain from the 3rd to 7th month.


By what month do the testis reach the scrotum?

Testes reach the scrotum by 9th month, just before birth.


What happens to the processus vaginalis in a male?

Within the first year, the processus vaginalis obliterates leaving a remnant round the testes tunica vaginalis


What can happen if part of the processus vaginalis remains?

Parts of processus vaginalis may remain unused leaving small cysts.

They can produce fluid and swell. If processus vaginalis remains open to abdominal cavity, intestines may protrude through inguinal canal - indirect inguinal hernia.


Which ducts, mesonephric or paramesonephric are preserved in males?

Mesonephric ducts are preserved in males.

Paramesonephric ducts preserved in females.


When gene drives the development of male genital ducts?

SRY gene encodes testis determining factor (TDF).


What does TDF cause epithelial cells to differentiate into?

TDF causes differentiation of epithelial cells into Sertoli cells.

Sertoli cells secrete anti-mullerian hormone. (AMH). AMH causes degeneration of paramesonephric ducts.


What do Sertoli cells cause the mesoderm of the gonad to differentiate into?

Sertoli cells cause mesoderm of the gonad to become Leydig cells, which produce testosterone. Testosterone promotes the survival and further development of mesonephric ducts.


What does the mesonephric duct differentiate into in the male?

The mesonephric duct develops into efferent ductules, epididymis, vas deferens and seminal vesicle.


What are the derivatives of the paramesonephric duct in the male?

The remnants of the paramesonephric duct persist as appendix testis and utriculus prostaticus.


What do the 3 parts of the paramesonephric duct become in the female?

The cranial and horizontal parts become the uterine tubes. The caudal parts fuse to from the uterine canal.


What divides into the the urogenital sinus and anus?

The cloaca divides into the urogential sinus and anus.


What does the urigenital sinus develop in a female?

The urogenital sinus develops sinovaginal bulbs that fuse with caudal tips of paramesonephric ducts to form vagina.


As the cloacal folds untie anteriorly, what do they form?

Cloacal folds unite anteriorly to form genital tubercle - future penis or clitoris.


What do genital swellings eventually become?

Genital swellings appear next to urethral folds - future scrotum or labia majora.


What is the development of external male genitalia dependent on?

Development of external male genitalia is dependent on androgens.

Genital tubercle elongates to form phallus. Genital swellings enlarge and move caudally.


At which week can you determine sex

Week 13.