SFP: renal embryology Flashcards
What is the tissue of origin for the kidneys-ureters?
Intermediate mesoderm
What is the tissue of origin for the bladder and distally?
Endoderm
What are the three sets of kidneys in fetal development?
Pronephros, mesonephros, metanephros
Which of the fetal kidneys produce urine?
Mesonephros, metanephros
From which fetal kidney does the adult kidney derive?
Metanephros
When does the ureteric bud form?
Week 5
In males, what happens to mesonephric ducts?
They become the epididymis, ductus deferens, and ejaculator duct
In males, what happens to mesonephric tubules?
They become efferent ductules
In women, what happens to mesonephric ducts and tubules?
They have no functional derivatives and regress
What are the essential tissue masses required for the kidneys to develop?
Ureteric bud and metanephric mass; epithelial to mesenchymal interactions
What process forms epithelium of developing tubules?
MET
What is reciprocal induction?
Process of different tissues causing changes in each other due to secreted signals
What is GDNF?
Hormone secreted by metanephric cells that aids in ureteric bud formation by producing bud branching and promoting bud growth
What is the receptor for GDNF?
c-Ret
What is BMP?
It inhibits growth of the ureteric bud
What blocks BMP?
Gremlin
What does the ureteric bud form?
Ureters, renal pelvis, calyces, papillary ducts, collecting ducts, collecting tubules
What does the metanephric mass form?
Renal corpuscle, proximal tubule, loop of Henle, distal convoluted tubule
What cell lineages are involved in forming a nephron?
Epithelial, mesenchymal, vascular endothelial
What is the epithelial element of the nephron?
Ureteric bud
What is the mesenchymal element of the nephron?
Metanephric blastema
What is the vascular endothelial element of the nephron?
The surrounding mesoderm
Describe the positioning of the kidneys in weeks 6-9.
They rotate medially and ascend into their abdominal position
What structures is mesoderm responsible for?
Allantois, bladder, cloaca
What causes renal agenesis?
Lack of one of the tissue masses or lack of signaling
What does bilateral renal agenesis cause?
Decreased amniotic fluid (oligohydramnios)
What causes renal hypoplasia?
Abnormal signaling during development
What can happen to the normal kidney in renal hypoplasia?
Hypertrophy
What causes supernumerary kidney?
Development of two ureteric buds
What causes duplications of the ureter?
Splitting or branching of the ureteric bud
What is pelvic kidney? What causes it?
one kidney staying in the pelvis caused by abnormal migration
What is crossed ectopia?
Abnormal migration causes two kidneys on the same side of the body that fuse
What is horseshoe kidney?
Fusion of the kidneys as they begin to migrate; medial rotation is prevented
What causes polycystic disease of the kidney?
Mutations in PKD1 or PKD2
What causes ectopic ureteral orifices?
Metanephric diverticulum being in an abnormal location
What complications arise from abnormal obliteration of the urachus?
Fistula, sinuses, and cysts
What is the normal amount of amniotic fluid?
500-1000 mL
What are the 4 sources of amniotic fluid?
- Diffusion through the decidua parietalis
- Diffusion through chorionic plate
- Diffusion through the skin before keratinization
- Renal and GI systems
What are functions of amniotic fluid?
- Growth without pressure
- Barrier to infection
- Normal expansion of fetal lungs
- Prevents the fetus from adhering to the amnion
- Cushions against injury
- Controls embryo body temperature
- Enables the fetus to move freely, aiding muscular development
- Maintaining homeostasis of fluids and electrolytes
What is a normal AFI?
8-18
