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

Explain the energy - releasing metabolic process, The energy - releasing me...

The energy - releasing metabolic process in which substrate is oxidised without an external electron acceptor is known as: 1. Glycolysis 2. Fermentation 3. Aerobic respira

Lungs - respiratory organs, Lungs - Respiratory Organs In arachnid art...

Lungs - Respiratory Organs In arachnid arthropods such as scorpion and spider, respiration takes place by means of book lungs. There are four pairs of these structures in the

What are respiratory pigments, What are respiratory pigments? What is the r...

What are respiratory pigments? What is the respiratory pigment present in some arthropods? Which is the analogous molecule in humans? Respiratory pigments are molecules able t

Define the disorders due to the iodine deficiency, Define the Disorders due...

Define the Disorders due to the iodine deficiency? Mild goitre, i.e., a larger thyroid gland than normal. The mildest form of goitre ranges from those only detectable by to

Inrinsic conduction system of the heart, The cardiovascular system controls...

The cardiovascular system controls the movement of blood through thousands of miles of capillaries so that every tissue  in every part of the body is perfused. Essential nutrients

Where would expect to see its growth, If you inoculate an organism know to ...

If you inoculate an organism know to chemically reduce sulfur (as done by organisms capable of anaerobic respiration), where would you expect to see its growth in the test medium u

Determine about the diseases sleep attacks, Determine about the diseases Sl...

Determine about the diseases Sleep attacks These are brief, often irresistible, episodes of sleep, probably slow wave, NREM, naplike sleep that last about 15 minutes and can oc

Obesity a health hazard, Obesity a health hazard: The factors of obe...

Obesity a health hazard: The factors of obesity are complex. Obesity is due to over eating and excess of energy intake. The obese child when grows up will be a target

What are atherosclerosis, Atherosclerosis, the most common part of hardenin...

Atherosclerosis, the most common part of hardening of the arteries, is characterized by the presence of cholesterol-rich arterial thickenings (atheromas).  This progressive  diseas

What type of selection is being demonstrated, If a cow develops a preferenc...

If a cow develops a preference for eating white four o'clock flowers and ignoring pink and red four o'clock flowers, what type of selection is being demonstrated? Would the cow eve

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