Embryology Flashcards
Name the 3 sets of kidneys which develop and their location
pronephros - cervical
mesonephros - thoracolumbar
metanephros - pelvis
Which of the 3 sets of kidneys are functional?
mesonephros are briefly, but metanephros are
What does the cloaca divide to form?
rectum
urogenital sinus anteriorly
What does the mesonephric duct drain into?
urogenital sinus
What does the urogenital sinus go on to form?
urinary bladder
cranial end = urethra
What is formed by the medial part of mesonephric ridge thickening?
genital ridge
How is the indifferent gonad formed?
germ cells from the yolk sac migrate into the genital ridge
Explain the paramesonephric duct
epithelium of mesonephros invaginates
develops lateral to the developing gonads and mesonephric duct
What does the cranial end of the paramesonephric duct open into?
peritoneal cavity
What does the gonad form in the male and female?
testis
ovary
What does the mesonephric duct form in the male and female?
epididymis, vas deferens, seminal vesicles
degenerates in females
What does the paramesonephric duct form in males and females?
fallopian tube, uterus, cervix
degenerates in males
Urogenital sinus forms what in males and females?
both = urinary bladder
urethra and prostate
vagina
How does the indifferent gonad know to form testis or ovaries?
on Y chromosome is a SRY encoding for TDF –> male
no Y chromosome = ovary
What is the prostate an outgrowth from?
urethra
What influences the formation of the male external genitalia?
testosterone
How many primordial follicles are there at birth?
2 million
atretic
breakdown of follicles
appearance of post menopausal ovary
fibrosed
The absence of testosterone causes the degeneration of what 2 structures?
mesonephros and mesonephric duct
Cranial end of paramesonephric duct is associated with…
ovary
caudal end of paramesonephric duct becomes…
uterus and superior vagina
Inferior vagina forms from what structure?
urogenital sinus
Where do the gonads originally form?
lumbar region
