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

Stage of meiosis, briefly describe the eggs and follicles, in rabbit

briefly describe the eggs and follicles, in rabbit

Change in symptoms of aortic stenosis, Q. Change in symptoms of aortic sten...

Q. Change in symptoms of aortic stenosis? Asymptomatic severe aortic stenosis patient needs to be followed once in a year or even more frequently. Patients with moderate aortic

In hormonal terms why does menses occur, Q. In hormonal terms why does mens...

Q. In hormonal terms why does menses occur? Menses is the endometrial monthly desquamation that occurs as the progesterone and estrogen levels fall after the regression of the

Determine the blood plasma levels of glucose, Which of the following serves...

Which of the following serves as an actuating signal, or as part of an actuating signal, in a negative feedback system? A. Blood plasma levels of Glucose. B. Blood plasma le

Defines the tenants of pangenesis theory, Defines the tenants of Pangenesis...

Defines the tenants of Pangenesis Theory Which of the following best defines the tenants of Pangenesis Theory? A. The hereditary material is composed in every organ/tissue a

Proteins of plant origin - seed proteins, Proteins of Plant Origin - Seed P...

Proteins of Plant Origin - Seed Proteins Seed Proteins: Although a large number of plants produce seeds having protein contents in excess of 15%, only a few are utilized for fo

Phase (different interference) contrast microscopy, Phase (different interf...

Phase (different interference) Contrast microscopy: Living cells are mostly   transparent. For viewing under ordinary light microscope, therefore, live cells must be stained wi

Describe class aves in details, Describe Class Aves in details? Class ...

Describe Class Aves in details? Class Aves: The fossil record contains evidence that birds evolved from the reptiles. Birds share anatomical features with Protoavis and Archa

Gastropods - feeding and digestion in molluscs, Gastropods - Feeding and Di...

Gastropods - Feeding and Digestion in Molluscs In several gastropods the digestion is extracellular. Though, some herbivore gastropods like Crepidula are ciliary feeders and h

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