Urogenital (kidney and lung)
Kidney, ovary, testis, efferent ducts and secondary sexual glands
o Vertebrates: the 2 organ systems are connected
o Invertebrates: the 2 organ systems are not connected
Connection between kidney and gonads is of medical importance (urology)
Gonads + kidney + efferent ducts– mesodermal
Lungs + vagina + prostate – endodermal – develops from the gut and from pharynx
(keelholte)
Evolution of kidney and testes
Jawless fish (cyclostomes):
o Kidney: elongated organ that extend through
whole body. It has its own duct the
archinephric duct
o Testes: elongated organ that extend through
whole body. It has not its own efferent duct,
so sperm is shed in body cavity and leave
body cavity through small cannels
Gnathostomes: Kidney and tests use the same
efferent duct.
Urodeles: Kidney and testes have separate ducts
Amniotes (mammels, birds, reptiles):
o Kidney: has a new duct (ureter)
o Testes: the archinephric duct (ductus deferens) continues to
serve the testes
3 kidneys in embryonic development of chicken
1. Pronephros:
a. Small: no efferent duct
b. In neck region
c. Not functional in humans – degrade in 4-5 weeks
2. Mesonephros:
a. Efferent duct (archinephric duct)
b. In abdomen
c. Functional in foetus
Mesonephros archineprhic duct cloaca: urine, sexual ductus and
gut end here urachus tube umbillical cord
placenta mothers blood mothers kidney
3. Metanephros:
a. Efferent duct (urether)
b. Adult kidney
Gonad initailly is undifferentiated
Both male and female efferent ducts are formed
Wolffian serves as mesoneprhos (archinephric duct) en Mullerian
stretches to the outside and opens in the coelom
At week 6 SRY is activated and mesonephros is degenerate
Kidney, ovary, testis, efferent ducts and secondary sexual glands
o Vertebrates: the 2 organ systems are connected
o Invertebrates: the 2 organ systems are not connected
Connection between kidney and gonads is of medical importance (urology)
Gonads + kidney + efferent ducts– mesodermal
Lungs + vagina + prostate – endodermal – develops from the gut and from pharynx
(keelholte)
Evolution of kidney and testes
Jawless fish (cyclostomes):
o Kidney: elongated organ that extend through
whole body. It has its own duct the
archinephric duct
o Testes: elongated organ that extend through
whole body. It has not its own efferent duct,
so sperm is shed in body cavity and leave
body cavity through small cannels
Gnathostomes: Kidney and tests use the same
efferent duct.
Urodeles: Kidney and testes have separate ducts
Amniotes (mammels, birds, reptiles):
o Kidney: has a new duct (ureter)
o Testes: the archinephric duct (ductus deferens) continues to
serve the testes
3 kidneys in embryonic development of chicken
1. Pronephros:
a. Small: no efferent duct
b. In neck region
c. Not functional in humans – degrade in 4-5 weeks
2. Mesonephros:
a. Efferent duct (archinephric duct)
b. In abdomen
c. Functional in foetus
Mesonephros archineprhic duct cloaca: urine, sexual ductus and
gut end here urachus tube umbillical cord
placenta mothers blood mothers kidney
3. Metanephros:
a. Efferent duct (urether)
b. Adult kidney
Gonad initailly is undifferentiated
Both male and female efferent ducts are formed
Wolffian serves as mesoneprhos (archinephric duct) en Mullerian
stretches to the outside and opens in the coelom
At week 6 SRY is activated and mesonephros is degenerate
