Kidney Embryology Flashcards
What ducts does the kidney develop from?
Mesonephric
What are the embryo ducts?
Mesonephric/Wolffian duct (males)
Paramesonephric/Mullerian duct (females)
What do the embryo ducts form?
Mesonephric/Wolffian = epididymis, vas deferens, seminal vesicles Paramesonephric/Mullerian = uterine tubes, uterus, cervix, upper 1/3 of vagina
What are the main embryo structures in regards to kidney development?
Ducts - Wolffian/mesonephric and Mullerian/paramesonephric
Immature gonads
Mesenchyme
How do the embryo ducts develop differently for males and females?
- Males: Mullerian/paramesonephric degenerates and mesonephric/Wolffian becomes male reproductive duct (lower part from the ureteric bud)
- Females: Wolffian/mesonephric degenerates apart form the lower part forming the ureteric bud and the Mullerian/paramesonephric forms the oviduct
What are the different embryological parts of the kidney?
Pronephric
Mesonephric
Metanephric (functional)
What is the most important embryological kidney part?
Metanephric
- forms the adult kidney
- functional
- formed from mesonephric duct
What are the parts of the metanephric kidney part?
Ureteric bud
Metanephric bud
What does the ureteric bud form?
Minor calyces
Major calyces
Renal Pelvis
Ureter
What does the metanephric bud form?
LOH DCT PCT Glomerulus and glomerular capillaries Bowman's capsule
What is the fate of the ureteric bud?
Comes into contact with the mesenchyme on the lateral side of the embryo and bifurcates into major calyces.
Major calyces divide into minor calyces which divide into collecting tubules
These structures are surrounded by the mesenchymal mass
How does the kidney ascend from the pelvic region?
Metanephros originates in the sacral region at S1 and ascends to the lumbar region at T12 as the embryo unfolds
Renal arteries degenerate in the sacral region and new ones from at the end of ascent in the lumbar region
What is the fate of the metanephric bud?
Fuses with the collecting duct and forms other structures (DCT, LOH, PCT, glomerulus/Bowman’s capsule/glomerular capillaries)
What is the function of the kidney at the end of the 1st trimester?
Generates amniotic fluid
Placenta responsible for excreting waste products
How is the amniotic fluid recycled?
Kidney produces amniotic fluid, fetus swallows it, kidney excretes it into amniotic fluid again
What are the main congenital pathologies of the kidney?
- polycystic kidney
- kidney agenesis
- bifid ureter
- ectopic pelvic kidney
- horseshoe kidney
What are the features of kidney agenesis?
Ureteric bud does not form and so the mesenchyme doesn’t receive any signals to form the kidney
Unilateral -> common, asymptomatic
Bilateral -> rare, don’t survive after birth, oligohydramnios, birth defects (club foot and lung defects)
What are the features of bifid ureter?
Ureter splits into 2 forming a duplicate kidney or duplicate ureter
Common and doesn’t affect kidney function
What are the features of ectopic pelvic kidney?
1 kidney stays in pelvic region and does not ascend
Both kidneys stay in pelvic region and fuse forming a pancake kidney
Still functional
What are the features of a horseshoe kidney?
Kidneys fuse in the pelvic region and try to ascend however get stopped by the IMA and so ascend around it forming a U shape
Common and functional
What are the features of polycystic kidneys?
Fluid filled cysts develop
Kidneys can fail
Cysts originate as dilations on the tubule -> enlarge and lose nephron contact -> become secretory in the epithelium increasing fluid secretions -> increased proliferation of cysts in the epithelium
What are the causes of polycystic kidneys?
Autosomal Dominant = polycystin mutation, either PKD-1 which is more common or PKD2
Autosomal Recessive = fibrocystic mutations
What is polycystin?
In the primary cilia for cell adhesion, calcium transport and cell cycle functions
