Urogenital Embryology Flashcards
What are the three pre- kidneys that develop prior to the actual kidney.
And what weeks do each form?
Pronephros - week 4 - cervical region
Mesonephros - week 5 - thoracic region
Metanephros - End of week 5 - pelvic region
During mesonephros phase, excertory ducts form which join into a structure that has also formed. this other structure will remain and be important in the genital formation in males, what is it?
Mesonephric duct
The Metanerphros is formed by two distinct parts, what are they?
Ureteric Bud
Metanephric Cap/ Mesenchyme
At the bottom of the mid-gut is the ‘Drain’ which will eventually split into two, what is it called?
Cloaca
What week do the kidneys become functional?
Week 11/ 12
What creates the divide in the cloaca?
Urorectum Septal
What are the two areas that are created by the urorectum septal?
Urogenital sinus
rectum/ anal canal
What week does the urorectum septal occur?
week 4 - 7
Where does the bladder develop from?
what part does not form from here?
Cranial section of the urogenital sinus.
trigone region does not form from here.
What are the two duct systems present in the fetus - both male and female to begin with.
mesonephric duct
Paramesonephric duct
Where to the premordial germ cells derive from?
Epiblast
What cells make AMH?
Sertoli cells
When does the external genitalia start to develop?
week 3
What action does testosterone have on the genital tubercle?
promotes it to elongate into a phallus
What structure guides the gonads down through the inguinal canal?
Gubernaculum
The outgrowth of the phallus in males is dependent on what?
Testosterone
The genital tubercle elongates to form the penis and genital swelling enlarge to form scrotal pouches, what are these dependent on for formation?
Dihydrotestosterone
When does testicular descent occur?
Between 10th week
What are the three stages of testes decent?
Regress of the cranial suspensory ligament at the cranial end of the testes
Transabdominal descent
Trans-inguinal decent - via the gubernaculum
When does the final stage of testicular descent occur?
In final weeks of pregnancy
What structures does the cloaca form?
Anus
Urethra
What do the urethral folds become?
Male: Scrotal Raphe & ventral of penis
Females: Labia minora
What do the genital swellings become?
Female: Labia Majora
Male: Scrotum
What causes enlargement of the Gabernaculum and when does it occur?
INSL-3 and AMH
weeks 8-15
What causes the gabernaculum to start to decent? and when does it occur?
Testosterone
Weeks 28-38
