Eggs of poultry

Eggs

    The egg is a complex structure distinguished by having four very different main parts ;these are yolk,albumen,shell membranes,and shell.

            The blastoderm is a small disc that contains the genetic code of the egg.The blastoderm lies on the surface of an almost spherical yolk.Yolk material is enclosed in a delicate elastic membrane.

             Two chalazae are firmly attached on the surface of the yolk membrane.They are positioned either side of yolk.The chalazae are long twisted fibres.The other ends of the chalazae are interlaced with fibres in the albumen.Their purpose is to stabilise the position of the yolk and hold it near the geometric centre of the egg.

                 The albumen surrounds the yolk and acts as a shock absorber also a supply of some nutrients.There are three layers of albumen.A liquid albumen surrounds the yolk.This accounts for one-sixth of the total albumen. A middle layer contains a thicker albumen that has a higher concentration of mucin fibres.This layer accounts for 57%of the total albumen in the eggs of domestic fowl. The outer albumen layer is next to the shell and is similar in composition to the inner albumen layer .The two different albumen types are often described as thick and thin albumen.

              Two membranes seperate the albumen from shell.Each membrane consists of a matrix of fibres that allow gases and liquids to diffuse through.