Intermediate mesoderm
Encyclopedia
Intermediate mesenchyme or intermediate mesoderm is a type of mesoderm
that is located between the paraxial mesoderm
and the lateral plate.
It develops into the part of the urogenital system (kidney
s and gonad
s)
Mesoderm
In all bilaterian animals, the mesoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and endoderm , with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme , mesothelium, non-epithelial blood corpuscles and...
that is located between the paraxial mesoderm
Paraxial mesoderm
Paraxial mesoderm is the area of mesoderm that forms just lateral to the neural tube on both sides.It differentiates rostrally into somatomeres and caudally into somites.It gives rise to the somitomeres/somites and mesoderm of the branchial arches....
and the lateral plate.
It develops into the part of the urogenital system (kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s and gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...
s)
- forms of urogenital system
- series of short evaginations from each segment grows dorsally caudally
- vestiges of the future kidneyKidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
, the pronephrosPronephrosPronephros the most basic of the three excretory organs that develop in vertebrates, corresponding to the first stage of kidney development. It is succeeded by the mesonephros, which in fish and amphibians remains as the adult kidney. In amniotes the mesonephros is the embryonic kidney and a more...
briefly appears. - pronephric ductPronephric duct-Development:The development of the pronephric duct is a part of the development of the urinary and reproductive organs.In the outer part of the intermediate mesoderm, immediately under the ectoderm, in the region from the fifth cervical segment to the third thoracic segment, a series of short...
arises in the intermediate mesoderm just ventral to the anterior somiteSomiteA somite is a division of the body of an animal. In vertebrates this is mainly discernible in the embryo stage; in arthropods it is a characteristic of a hypothetical ancestor.- In vertebrates :...
s - grows caudally until it becomes the cloacaCloacaIn zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
. - it is distinct from the lateral mesoderm, as it is not influenced by the secretion of BMP-4 by the ectodermEctodermThe "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...
, possibly due to the lack of receptors.
