BIOL 3010 Lecture Notes - Basic Fibroblast Growth Factor, Cell Migration, Tx Network
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Kidney
Takehome Messages:
- Kidney is derived from intermediate mesoderm
- Uretic bud tip as a classical inducer
- Reciprocal induction between bud tip and blastema
- many growth factors are involved
NEPHRON ANATOMY
Urinephrous tubule:
- Nephron – from blastema
- Collecting Ducts – from uretic bud of mesonephric duct
Nephron = renal corpuscle + proximal, distal tubules
corpuscle = Bowman’s capsule + glomerulus (capillaries)
Bowman’s capsule: visceral portion is lined w/ podocytes
(parietal is ss epithelium)
Glomerulus: thick basement membrane – filtration barrier
site of genetic disease
vascular pore – where glomerular vessels enter corpuscle
urinary pore – where distal convoluted tubule leaves
Urinephrous Tubule
nephron, blastema
mesonephric duct
corpuscle
Bowman’s capsule,
glomerulus
podocytes
basement membrane
vascular pore
urinary pore
Kidney
DEVELOPMENT:
PRONEPHROS –
mesenchymal epithelial transition of intermediate mesoderm
tube formation progresses anterior caudal
- duct induces adjacent mesenchyme to form pronephric
kidney tubules (no function in mammals)
MESONEPHROS –
forms in the nephrogenic cord (separate from wolffian duct)
mesonephric tubules = nephrotomes
connected via mesonephric (WOLFFIAN) duct
duct empties into urogenital sinus (bladder + urethra)
Wolffian duct persists in male reproductive system
METANEPHROS –
ureteric bud emerges from Wolffian duct and grows dorsally
eventually forms URETER and COLLECTING DUCTS
induces mesenchyme to form nephrons
nephrons then induce branching of bud (reciprocal ind.)
CLASSICAL INDUCTION –
distal tip of ureteric bud induce BLASTEMA formation
blastema (aka nephron vesicle) nephron
tips of distal tubules eventually connect to collecting tubule
RECIPROCAL INDUCTION –
nephron-forming tissue induces branching of the bud
leads to formation of 1-million nephrons
blood vessels follow ureteric bud glomeruli
TERMINAL DIFFERENTIATION –
tubules elongate
epithelial cell polarity
pump/channel expression
proneprhos
pronephric tubules
mesonephros
nephrogenic cord
nephrotomes
Wolffian Duct
metanephros
ureteric bud
reciprocal induction
blastema