Urinary Embryology Flashcards
What are the components of the urinary system?
Kidneys
Ureter
Bladder
Urethra
What are the components of the kidneys?
Nephron
Collecting duct
Calyces and pelvis
What is the role of the urethra?
Takes the urine from the bladder to the exterior of the body
Which part of the mesoderm forms the urogenital system?
Intermediate plate mesoderm
What is the allantois?
Pouch of the endoderm at the hindgut which extents into the body stalk.
What happens in the allantois?
Waste products are collected- they then go into the umbilical cord and through the placenta into the maternal system
Cloaca?
Single posterior opening for a bird’s digestive, urinary and reproductive tracts
->for poo and eggs x
What does the allantois grow to become?
Body stalk which then goes on to form the umbilicus
What happens to the cloaca in humans?
Is divided by mesoderm into an anterior and posterior part
What does the cloaca divide into posteriorly?
Rectum
What does the cloaca divide into anteriorly?
Urogenital sinus
What does the urogenital sinus go onto form?
Urinary bladder
What does the allantois go onto form?
Urachus*
*a remnant of a channel between the bladder and the umbilicus where urine initially drains in the fetus during the 1st trimester of pregnancy.
What happens to the allantois after birth?
Gets obliterated and forms anterior part of bladder
What happens to the intermediate mesoderm in the neck region during the fourth week of development?
Becomes the pronephros
What does the pronephros become?
Pronephric duct
Rudimentary pronephric tubules
What does the pronephric duct drain into?
Cloaca
During which week of development does the pronephros mainly degenerate, except from the pronephric duct?
5th week
What does the pronephric duct become?
Mesonephric duct
What takes over from the pronephros?
Mesonephros
What is the role of the mesonephros?
Functions as the kidneys for four weeks
After four weeks, the mesonephros starts the degenerate, what takes over?
Metanephros
What does the metanephros become?
Definitive kidney
What does the metanephros consist of?
Ureteric bud that comes off the mesonephric duct
Metanephric mesoderm
What do the mesonephric tubules become?
Testes
->in females, the mesonephros becomes the ovary but the ducts and tubules degenerate
What does the mesonephric duct become?
Vas deferens
Where is the definitive kidney formed from?
Metanephric mesoderm, part of the intermediate mesoderm
Where is the ureter formed from?
Ureteric duct
The uretic bud undergoes repeated branching at it’s distal end.
What do the first 4 generations of branches become?
Major calyces
->next four generations become the minor calyces, remaining generations form the collecting tubules
What does the nephron develop from?
Metanephric mesoderm
List the structures that develop from the ureteric bud.
Ureter, collecting duct, calyces
At what vertebral level do the kidneys end up at?
T12-L3
What is meant by a horse-shoe shaped kidney?
The lower poles of the two kidneys fuse together causing a horseshoe shape
