Embryonic Development

The germ (blastodisc) is a small white spot on the yolk where the embryo develops - it's the most important part biologically as it becomes the chick. The yolk provides nutrients, the white (albumen) provides protein and protection, and the shell membrane is part of the protective layer.

The air cell forms between the inner and outer shell membranes at the larger (blunt) end of the egg. As the egg cools after being laid, the contents contract more than the shell, creating this air pocket at the wider end where the membranes separate. The air cell provides the developing chick with oxygen during the final stages of incubation when it internally pips.

The germ spot (also called the blastodisc) is a small white disc on the yolk surface where the embryo develops. It's the most important part because it contains the genetic material that becomes the chick. The yolk and white provide nutrition, but the germ is the actual living part.

The air cell (or air pocket) forms at the larger, blunt end of the egg as it cools after laying. This is a standard anatomical feature of bird eggs, created by the separation of the inner and outer shell membranes at that end. The smaller end has no air cell.

The germ spot or blastodisc is a small white disc on the yolk surface from which the embryo develops. It's the most important part as it contains the genetic material that becomes the chick.

The air cell forms between the shell membranes at the larger end of the egg. As the egg cools after laying, the contents contract and air enters through the pores, creating this pocket at the blunt end.

Here the placentas are located in a central column within a non-sectioned ovary of the flowers. The prominent example is Portulaca.

An egg apparatus is consisted of group of three cells in the seven-celled embryo sac of an angiosperm consisting of the egg cell and two associated cells called synergids. It is located at the end of the embryo sac.

In human beings after one month of pregnancy, the embryo’s heart is formed.

5-7 days after fertilization, the blastocyst attaches to the wall of the uterus (endometrium). When it comes into contact with the endometrium it performs implantation.

The germ layers in organogenesis differ by three processes: folds, splits, and condensation.

Heart, circulatory system and muscles are mesodermal in origin.

Trophoblast cells in contact with embryonal knob are called cells of rauber.

In mammals, decidua basalis is a part of placenta. 

Paramesonephric ducts are paired ducts of the developing foetus that run down the lateral sides of the urogenital ridge. In females, they develop to form fallopian tubes, uterus, cervix and the upper two-thirds of vagina.