Epiboly of ectoderm, Biology

Assignment Help:

Epiboly of Ectoderm

Like the presumptive endodermal notochordal and mesodermal cells migrate inward the areas in the epiblast vacated through them are occupied by expansion (epiboly) of the embryonic epidermal and neural ectoderm. At the same time with gastrulation the ectodermal cells expand as a sheet beneath the vitelline membrane outward from the area opaca finally encircling the yolk. The upper surfaces of ectodermal cells of area opaca are in from contact with the inner surface of vitelline membrane and they spread along this inner surface of the membrane. Also, these cells extend pseudopodia processes which attach to inner side of the vitelline membrane. It appears that these marginal cells of area opaca migrate outward along the inner surface of the vitelline membrane with the help of these pseudopodia and at the same time drag along the expanding sheet of ectodermal cells of that they are the leading members. Removal of the vitelline membrane inhibits epibolic movements and expansion of ectoderm.


Related Discussions:- Epiboly of ectoderm

Short coming of cell theory, SHORT COMING OF CELL THEORY / EXCEPTIONS OF CE...

SHORT COMING OF CELL THEORY / EXCEPTIONS OF CELL THEORY (i)       Viruses can be considered as exception to cell theory. They are made of proteins and ones of nucleic acid i.e.

Intravenous route, Intravenous Route This route of administering drug...

Intravenous Route This route of administering drugs is becoming more popular in the paediatric practice. Purpose of this Route When rapid action is required.

Ozone layer and its depletion, About 90% of ozone of atmosphere resides in ...

About 90% of ozone of atmosphere resides in stratosphere (16 to 40 km) layer of atmosphere as ozone layer. It protects life on this planet from harmful U.V. radiations. In absence

Define chromatography - basic separation technique, Define Chromatography -...

Define Chromatography - Basic Separation Technique? Chromatography is the most effective technique for the separation, purification and identification of one or more biological

Explain lock and key model, Fischer 's template or lock and key model ...

Fischer 's template or lock and key model According to this model, the catalytic site of the enzyme has a proper conformation compatible to a specific substrate even  in  the a

State the types of blood vessels, Blood Vessels There are three types o...

Blood Vessels There are three types of blood vessels. They are: 1) Arteries: Arteries carry blood from heart to different organs. They have thick wall. 2) Veins: Vein

Explain the sedimentation - air sampling, Explain the Sedimentation - Air S...

Explain the Sedimentation - Air Sampling? It is the simplest method, which involves exposing agar plates in air for specified time at a location to be sampled.  Microorganisms

AP Biology, Explain the difference between endoparasite, ecctoparasite, and...

Explain the difference between endoparasite, ecctoparasite, and parasitoidism

Transcribed regions, Transcribed regions The transcribed regions of the...

Transcribed regions The transcribed regions of the genes contain a number of regulatory elements that control exon splicing, mRNA transfer to cytoplasm translation, mRNA target

Excretory system - ureters, URETERS From hilum of each kidney emerge...

URETERS From hilum of each kidney emerges out a tube. Wall is thick. Lumen is star shaped. 28 cm. long. Transitional epithelium present in wall. Open in to urinary bla

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd