Renal embryology (Bendiak) Flashcards
What structures form from the ureteric bud?
Collecting tubules Collecting ducts Ureters Major calices Minor calices Renal pelvis
What are the metanephric spheroids? What structures develop from them?
The metanephric spheroids become the metanephric vesicle, then the metanephric tubule, and go on to form the remainder of the nephron (minus the ureteric bud structures).
Distal tubule cells and collecting duct cells come from completely different embryonic origins.
CD cells–> Ureteric bud
DCT cells–> metanephric blastema
What structures derive from the metanephric blastema?
The metanephric spheroids develop from the metanephric blastema. So, the remainder of the nephron develops from the mb, incliding the vascular structures: glomerulus, afferent and efferent arterioles, the vasa vasorum, etc.
From which structure does the ureteric bud arise?
The mesonephric duct (aka the wolffian duct)
Describe the development of the ureteric bud into its end structures.
Tubules grow outward from the bud to form the Malpighian Pyramids. The epithelia of these pyramids will become the collecting ducts of the kidney. These continue to branch to form the collecting tubules, then stop.
The urogenital sinus originates as _____, from a caudal structure called the _____. The urogenital sinus separates from the hindgut at approximately ____ weeks
endoderm; cloaca; 6-7
In males, the portion of the ureteric bud connected to the mesonephric duct moves to connect directly to the bladder. It eventually connects to the urethra and becomes part of the _____. So, what is unusual about the dermal origin of the prostatic urethra and the trigone?
prostatic urethra.
A portion of the bladder called the trigone or trigonal vesicle between the insertion of the ureter and Wolffian duct is actually of mesonephric origin, rather than endodermal like the rest of the bladder. In females, the Mulle- rian duct develops into the oviducts and uterus which will be cov- ered in reproductive development.
What is the timeline for the formation of the pronephros, the mesonephros, and the metanephros?
The pronephros (about 3 to 4 weeks), the mesonephros (about 4 weeks-2 months), and the metanephros (about 5 weeks to maturity).
What happens to the allantois and the cloaca?
Eventually, the portion of it called the allantois degenerates to form a fibrous cord called the urachus and the bladder and urethra develop from the urogenital sinus. The cloaca becomes the anorectal canal.
To what structures do the Wolffian ducts give rise?
Epididymus and ductus deferens.
To what structures do the Mullerian ducts give rise?
Oviducts and uterus.
