Difference between revisions of "Intermediate Mesoderm Development - Anatomy & Physiology"
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#Capillaries develop at the medial aspect of the intermediate mesoderm so that waste can diffuse from the blood to the excretory channel. | #Capillaries develop at the medial aspect of the intermediate mesoderm so that waste can diffuse from the blood to the excretory channel. | ||
#Connections between the intermediate mesoderm and somites as well between the intermediate mesoderm and lateral plate mesoderm break down. | #Connections between the intermediate mesoderm and somites as well between the intermediate mesoderm and lateral plate mesoderm break down. | ||
+ | |||
+ | ==Mesonephros== | ||
+ | |||
+ | *''Development occurs in an anterior to posterior direction; the mesonephros kideny is found at the thoracic to lumbar level''. | ||
+ | #The medial portion of the intermediate mesoderm forms a cup in the region of the capillaries. | ||
+ | #*This is an early Bowman's capsule and improves waste removal. | ||
+ | #The excretory channel pinches off from all surrounding tissue (lateral plate mesoderm) to become entirely closed. | ||
+ | #*Excretory duct now known as the '''Wolffian Duct'''. | ||
+ | *Amphibians and fish use the mesonephric kidney. |
Revision as of 14:26, 31 August 2008
Introduction
The intermediate mesoderm exists as a strip of tissue between the lateral plate mesoderm and somites. It gives rise to the urinary system and some parts of the reproductive system. Kidney development includes three forms:
- Pronephros
- Mesonephros
- Metanephros
Mammals develop all three, and continue to use the metanephros in adult life. More primitive animals have only the first one or two.
Pronephros
- The earliest kidney. Develops in the anterior of the animal (adjacent to somites 7 - 10). Eliminated in later development.
- At intervals along the intermediate mesoderm, dorsal evaginations occur.
- Evaginations extend caudally and eventually fuse with more caudal evaginations.
- The caudal - most evagination fuses with the cloaca.
- Forms a continuous excretory tube to the cloaca.
- Capillaries develop at the medial aspect of the intermediate mesoderm so that waste can diffuse from the blood to the excretory channel.
- Connections between the intermediate mesoderm and somites as well between the intermediate mesoderm and lateral plate mesoderm break down.
Mesonephros
- Development occurs in an anterior to posterior direction; the mesonephros kideny is found at the thoracic to lumbar level.
- The medial portion of the intermediate mesoderm forms a cup in the region of the capillaries.
- This is an early Bowman's capsule and improves waste removal.
- The excretory channel pinches off from all surrounding tissue (lateral plate mesoderm) to become entirely closed.
- Excretory duct now known as the Wolffian Duct.
- Amphibians and fish use the mesonephric kidney.