Embryology Flashcards
What does the paraxial mesoderm form?
somites
What does the intermediate plate mesoderm form?
urogenital system
What does the lateral plate mesoderm form?
body coverings and cavities
What is the allantois?
Outpouching of endoderm at hindgut that extends into the body stalk
What does the body stalk form?
umbilical cord
What is the cloaca?
single opening for urinary, reproductive and digestive system
What divides the cloaca?
urorectal septum
What is the cloaca divided into? Which is anterior and posterior?
urogenital sinus - A
rectum - P
What does the mesonephric duct drain into?
urogenital sinus
What does the urogenital sinus go on to form?
urinary bladder
urethra (caudal end)
What week does the pronephros form?
4
What forms the pronephros?
intermediate plate mesoderm in the neck
Name the 2 parts of the pronephros
rudimentary pronephric tubules
pronephric duct
What does the pronephric duct drain into?
cloaca
When does the propnephros degenerate by? What remains?
week 5
pronephric duct
What forms the mesopnephros and in what week is this?
intermediate plate mesoderm in trunk
late week 4
When does the mesonephros function?
week 5-9
What does the pronephric duct form?
mesonephric duct
What do the mesonephric tubules drain into?
mesonephric duct
What is the name for the definitive kidney?
metanephros
When does metanephros develop and then start to function?
week 5
week 9
2 parts of metanephros
ureteric bud metanephric mesoderm (most caudal part of intermediate plate mesoderm)
What happens to the mesonephros?
much incorporated into the gonads
What migrates to form spermatogonia and oogonia?
undifferentiated cells from the yolk sac
What do the mesonephric tubules form?
rete testis
What does the mesonephric duct form?
vas deferens
What happens to the mesonephric duct in females?
degenerates
What does the ureteric bud do?
branch at distal end
Stalk of ureteric bud forms?
ureter
Expanded cranial end of ureteric bud forms?
pelvis
first 4 branches of ureteric bud form
major calyces and become confluent
What do the second 4 branches of the ureteric bud form?
minor calyces
What do the remaining branches of the ureteric bud form?
collecting tubules
What do the ureteric bud and metanephric duct do to eachother?
reciprocally induce eachother
What comprises the nephron?
renal corpuscle + PCT + loop of henle + DCT
What comprises the uriniferous tubule?
nephron and collecting duct
What does the nephron develop from?
metanephric mesoderm
What does the collecting duct, calyces, pelvis and ureter develop from?
ureteric bud
Where do the kidneys initially lie?
side of bladder and developing pelvis
Why do the kidneys ascend into abdomen?
differential growth of the lower body
Where do the kidneys lie in an adult? (vertebrae level)
T12-L3
Where does the hilum rotate to?
from ventral to medial - 90 degrees
When does the kidneys ascent stop?
when they reach the adrenal glands
Describe the kidney vascular supply on their ascent
segmental breakdown and reform of vascular supply
