Embryo is unable to ingest food, to what do you attribute the change in size and shape.?

Question

This is about neurula.... The whole question actually was. Since the embryo is unable to ingest food at some time, to what do you attribute the change in size and shape from neurula to tail bud?

Answer 1

The embryo is fed by the placental connection between its mother and it. The mothers blood is rich in both oxygen and dissolved nutrients. This blood passes through the embyo in which it is able to take up these important products.

If you are talking about the embryo in an egg these things are provided by the yolk sac.

Answer 2

The morphological developmental changes going on in the neurula have nothing to do with ingestion. True, they need nutrients to stay alive (refer to the above post on that) but the developmental changes are due to the arrangement of pieces of tissue in the animal secreting special factors, usually proteins, called morphogens (among other things). One example is the generation of the neurula itself. During gastrulation (production of the 3 tissue layers - epidermis, mesoderm and endoderm) a structure called the notochord is generated underneath the dorsal surface of the embryo. This notochord releases a morphogen called Sonic Hedgehog (in humans....seriously) that induced overlying tissue to turn into neurectoderm (cells that will turn into the central nervous system(CNS)). This also causes them to bend inwards, or "invaginate", and form a tube called the "neural tube", which turns into the CNS. This is not the only secreted factor involved in this but I've simplified it to illustrate the point. Limbs, such as the tail you are mentioning, often have organizers (called the "limb bud") secreting, among other things, FGF that elongates and generated the limb.

So, yeah, developmental cues in the forms of gradients of secreted factors are what cause the shape changes and maturation that you see throughout development (it is a very reused tool, Nature sticks with what works), not nutrients. I should mention that sometimes cells can talk to each other by touching each other directly...that happens a lot too.

Answer 3

it is true that embryo cannot ingest food however the embryo is attached to the mothers womb by means of a tissue called placenta food digested by the mother is absorbed by the embryo through the placents which enables it to grow.in cases of tail bud the bud derives digested food directly from the parent body

Answer 4

Ingestion is a mechanism to make food availabl but in embryo it is already available so it is used to increase size

Answer 5

Neurula gets nutrients via blood vesicules inmersed on the spongy tissue that covers the uterus, so the neurula's cells get O2, glucose, minerals, proteins from mom's blood because placenta is not there yet!.
Matter and energy enter the neurula, so it can grow!