Urinary Development
During gastrulation, what three germ layers develop?
1. Epiblast
2. Mesoderm
3. Hypoblast
What are the three types of mesoderm? (give a brief description)
1. Paraxial
Forms somites
2. Intermediate
Lateral to somites and borders the intraembryonic coelomic space
3. Lateral
Splits into somatic and splanchnic layers with fluid-filled space
What does the intermediate mesoderm give rise to? (4)
The urogenital system:
Embryonic kidneys
Adult final kidneys
Urinary duct system
Gonads and reproductive duct system
What structure gives rise to the embryonic kidneys in mammals?
Mesonephros
What structure gives rise to the definite kidney in mammal?
Metanephros
What structure gives rise to the definitive kidneys in most fish and amphibians?
The mesonephros
, Why is there a close relationship between the urinary and reproductive system during their
development?
Both systems develop from the urogenital ridge:
Nephrogenic cord (lateral) ---> kidneys, urinary and reproductive ducts
Gonadal ridge (medial) ---> gonads
What happens to the mesonephros in mammalian foetuses? (Compare male and female)
Females:
The mesonephric kidney degenerates and regresses (completely in the female)
Males:
As it regresses part of the mesonephric excretory tubules and ducts are assimilated into the
testis and reproductive duct
Where does the kidney develop from?
The nephrogenic cord (nephrotome)
What are the three sets of kidneys that form during embryonic and foetal development?
Pronephros
Mesonephros
Metanephros
When and how does the pronephric kidney form?
First to form (cervical region, somites 5-8):
1. Nephrotome forms bilateral ducts (pronephric ducts)
2. These ducts elongate towards cloaca
3. Tubules extend from ducts (pronephric tubules)
NOTE not functional kidney in mammals (used as stepping stone to mesonephros)
Describe the characteristics of the mesonephric kidney (functions, blood supply, location,
formation and timings)
During gastrulation, what three germ layers develop?
1. Epiblast
2. Mesoderm
3. Hypoblast
What are the three types of mesoderm? (give a brief description)
1. Paraxial
Forms somites
2. Intermediate
Lateral to somites and borders the intraembryonic coelomic space
3. Lateral
Splits into somatic and splanchnic layers with fluid-filled space
What does the intermediate mesoderm give rise to? (4)
The urogenital system:
Embryonic kidneys
Adult final kidneys
Urinary duct system
Gonads and reproductive duct system
What structure gives rise to the embryonic kidneys in mammals?
Mesonephros
What structure gives rise to the definite kidney in mammal?
Metanephros
What structure gives rise to the definitive kidneys in most fish and amphibians?
The mesonephros
, Why is there a close relationship between the urinary and reproductive system during their
development?
Both systems develop from the urogenital ridge:
Nephrogenic cord (lateral) ---> kidneys, urinary and reproductive ducts
Gonadal ridge (medial) ---> gonads
What happens to the mesonephros in mammalian foetuses? (Compare male and female)
Females:
The mesonephric kidney degenerates and regresses (completely in the female)
Males:
As it regresses part of the mesonephric excretory tubules and ducts are assimilated into the
testis and reproductive duct
Where does the kidney develop from?
The nephrogenic cord (nephrotome)
What are the three sets of kidneys that form during embryonic and foetal development?
Pronephros
Mesonephros
Metanephros
When and how does the pronephric kidney form?
First to form (cervical region, somites 5-8):
1. Nephrotome forms bilateral ducts (pronephric ducts)
2. These ducts elongate towards cloaca
3. Tubules extend from ducts (pronephric tubules)
NOTE not functional kidney in mammals (used as stepping stone to mesonephros)
Describe the characteristics of the mesonephric kidney (functions, blood supply, location,
formation and timings)
