Embryology Flashcards
What is the embryological origin for the kidney?
mesoderm
What develops from the intermediate mesoderm?
nephrotome
What happens to the intermediate mesoderm at the cranial end?
begins to segment to form the pronephros
What are the pronephros?
a vistigial structure- is only temprorary
What develops alongside the pronephros?
the mesonephric duct
What happens later to the intermediate mesoderm more caudally?
segments to form the mesonephros
What is the mesonephros?
temprorary kidney between weeks 6-10 then regress once the kidney proper has developed
How do the mesonephros develop?
take on a nephron shape, connect to mesonephric duct
What does the kidney develop from?
metanephros (NOT mesonephros) the ureteric bud and metanephric blastema
What do the ureteric buds sprout from?
the distal mesonephric ducts
What is the metanephric blastema?
sacral portion of the intermediate mesoderm
How do the ureteric buds and metanephric blastema come to form the kidney?
ureteric bud sprouts to penetrate the metanephric blastema
What does the ureteric bud form?
the collecting system
What is the collecting system made up of?
ureter; renal pelvis; major calyces; minor calyces and collecting ducts
How does the ureteric bud grow into the metanephric blastema?
brances to separate the blastema- develop gross lobes
What happens after the ureteric bud has branched into the metanephric blastema?
insussuseption and then branches and then more intussusception
What is the purpose of the intussusception?
proximal branches coalesce again to create larger spaces to collect urine in
What does hte metanephric blastema form?
the nephrons
How does the metanephric blastema form the nephrons?
there is a small “cap” of blastema tissue at the end of the bud branches which form a vesicle which then fuses with the collcting system
Where do the kidneys develop in the embryo?
pelvis near the bifurcation of the aorta
What does the cloaca develop from?
hindgut endoderm
What does the cloaca form?
the rectum and the primitive urogenital sinus
What does the primitive urogenital sinus give rise to?
the bladder; pelvis urethra and the definitive urogential sinus
What is the allantois?
an opening from the cloaca into the umbilical cord
What originally connects with the bladder instead of the ureteric bud?
mesonephric duct- they need to switch
What does the mesopnephric duct form in the males?
vas deferens
What does the mesonephric duct form on its descent to switch places with the ureteric bud?
the smooth trigone
