The main nutrition of egg cells for embryonic development.

2, blastoderm

The yolk membrane is tightly wrapped around the yolk to protect the yolk.

3. Egg shell

Prevent egg cells from being damaged, reduce water evaporation, exchange gas with pores, and have the functions of support and protection.

4, egg white

It provides nutrition and water for embryo development and also protects egg cells.

5. Airbag

There is air in it, exchanging gas with cells.

6.shoelaces

Has the functions of fixing egg yolk and damping, and is beneficial to hatching.

Extended data

The reproductive organ that produces egg cells is the ovary of the female bird. There are many immature eggs in the ovary, and the eggs gradually mature in the ovary. One is mature, the other is excluded, leaving the ovary, falling into the body cavity and entering the fallopian tube.

Mature eggs produced by ovaries do not have the structure of protein, shell membrane and eggshell when they leave ovaries, but these structures only exist after the eggs are formed due to the secretion of the tube wall in the middle and rear part of fallopian tube during the movement.

Moreover, egg fertilization is the fusion of sperm and egg in the anterior fallopian tube-before the egg is wrapped by protein, shell and eggshell, not in the uterus-after the egg has formed an egg.

Therefore, protein, shell and eggshell do not belong to the structure of the egg itself (they are wrapped outside the egg, which is the adaptation of birds to its oviposition and reproduction mode), and the yolk part hanging in the center of the egg is the egg (when the fertilized egg forms an egg and lays eggs, the cleavage has progressed to the early blastocyst stage, and there is not only one cell in the egg, but many cells).

Baidu encyclopedia-eggs

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