Lecture 4- Embryology Flashcards
What does the urogenital system arise from?
Intermediate mesoderm
What does the intermediate mesoderm form?
Urogenital ridge
What does the urogenital ridge develop into?
Pronephros
Mesonephros
Metanephros
Pronephros
Most cranial set of tubes
Regresses
Mesonephros
Located along the midsection of the embryo
Develops into the mesonephric tubules and mesonephric ducts
Mesonephric tubules
Have some crude kidney function at first, but then mostly regresses
Mesonephric duct
Persists and opens to the cloaca at the tail of the embryo
Metanephros
Most caudal part of urogenital ridge
Forms adult kidney
Develops from the ureteric bud (outgrowth of caudal mesonephric duct) and the metanephric blastema (renogenic intermediate mesoderm)
Nephrogenic cord
Cleaves into nephrotomes
Nephrotomes hollows out into nephrotomal vesicle, which become oval and then S-shaped
The vesicles then fuse, which forms the pronephric duct
What does the ureteric bud give rise to
“Collecting system”
Ureter, renal pelvis, calyces, papillary ducts, and collecting ducts
Goes through consecutive rounds of bifurcation, elongation, and fusion
Metanephric blastema
Gets compressed by the ureteric bud and undergoes the same transformations described for nephrotomes
Gives rise to the nephrons or “excretory system”
Urine formation
Urine is actively formed during prenatal life, but isn’t required
After birth, no more functional units (nephrons) are formed
Describe changes in the position of the kidney
Metanephros is initially located in the pelvic region, but shifts to a more cranial position- “ascent” of the kidney
Hilum initially faces ventrally, but ends up facing medially
How are the urogenital sinnus and anorectal canal formed?
During the separation of the endodermal cloaca by the urorectal septum
Renal agenesis
One or both kidneys fail to develop
