Parts of an Egg

3 Newly Laid Eggs

Have You Ever Wondered About the Parts of an Egg?

 Until recently, I never did and I love eggs and think chickens are pretty cool.

To me there were only three parts to an egg and only two of them were important. The shell went in the trash and you ate the white and the yolk.

Simple as that!  

Well not really...

From a scientific standpoint it appears that there are at least 15 separate and specific parts of an egg that make up its anatomy.

Of these 15, there are 8 major parts that can be pretty easily identified and explained.

Working from the outside and moving inward, they are:

  • The Shell, this is the hard, protective outer covering of the egg. It is made up of primarily calcium, filled with 1000’s of small holes called pores that allow oxygen to move into the shell and carbon dioxide and moisture to move out allowing for the chick to breathe. It can be many different colors depending on the breed and what they’re fed.
  • The Membrane(s), there are 2, an inner and outer. They both do pretty much the same thing which is to act as a barrier against bacteria. The outer membrane is attached to the shell and the inner membrane is attached to the albumen (egg white).
  • The Air Cell, this is a pocket of air formed at the large end of the egg. A chicken’s body temperature is 106° F so the freshly laid egg is much warmer than the surrounding air. As the egg cools, it causes the albumen to contract pulling the inner membrane with it, creating an air cell.
  • Albumen, this is also known as the white part of the egg. This surrounds the yolk and is the space where the embryo develops and receives a large amount of the protein it needs to develop properly.
  • Chalaza, these are twisted cords that are part of the albumen at the top and bottom of the egg. They're twisted in opposite directions and their job is to keep the yolk centered in the egg.
  • Vitteline Membrane, this is a clear membrane that surrounds the yolk and is sometimes referred to as the yolk membrane. Its job is to keep the albumen (white) and the yolk from mixing. When they do mix it is called mottling. Mottling doesn't affect the quality of the egg, only the appearance.
  • The germinal disk, this is a small area on the outside of the yolk that contains the female’s genetic material. This is also where the sperm would enter creating fertilized chicken eggs.
  • The Yolk, this is the yellow part of the egg. It is filled many nutrients and protein for the growing embryo as well as all of the fat and cholesterol in an egg.

Well there you are; a semi scientific breakdown of the parts of an egg. Pretty cool stuff; I hope you enjoyed learning a little about it as much as I did.

Return from Parts of an Egg to Hatching Chicken Eggs

Protected by Copyscape Online Plagiarism Scanner