Noun:

ஒரு உறுப்பின் வளர்ச்சி நிலையில் அதைச் சரியாகத் தெரிந்து கொள்ளும் காலம்,

primordium's Usage Examples:

4 But, thus defined, the germ is neither more nor less than the "particula genitalis" of Aristotle, or the "primordium vegetale" or " ovum " of Harvey; and the " evolution " of such a germ would not be distinguishable from " epigenesis.

The primordium of the neurochord (neural or medullary plate) referred to above becomes closed in from the surface by the overgrowth of surrounding epiblast, and its edges also bend up, meet, and finally fuse to form a tube, the medullary or neural tube.

This raises the question as to how cells are organized into rosettes within the migrating primordium, and how the prepattern is maintained.

These pits are not isolated, but are connected by an ectodermal ridge, which grows in at the margin of the mantle and forms a continuous band somewhat resembling the ectodermal primordium of vertebrate teeth.

After invagination is completed, the embryo begins to elongate, the blastopore becomes narrower, and the dorsal wall of the gastrula loses its convexity, and becomes flattened to form the dorsal plate, the outer layer of which is the primordium of the neurochord and the inner layer the primordium of the notochord.

Synonyms:

organ, anlage,

Antonyms:

receptor, effector,