The egg - a female sex cell, which contains a haploid set of chromosomes.Its main purpose - the transfer of genetic information during fertilization.The structure of the egg in nature can be quite varied.For example, the egg - it's fish eggs, egg, etc.Each species of animal has its own characteristics.
Structure bird egg
Perhaps the most striking example of this structure are the eggs of birds and reptiles, which in many ways have a similar structure.Egg - a huge egg, which is easy to learn, with no special equipment.
egg poultry consists of yolk, albumen and shell.Each of these component parts has its own characteristics.The yolk is a dense, yellowish, circular structure located in the center of the egg.It contains many fats, proteins, vitamins, minerals and pigments eggs.Its main purpose - it is the power of the embryo.
Top yolk covered with a thin and dense yolk membrane, the surface of which can be seen a small bright spot - is blastodisc on the site which was the core of the egg before fertilization.
Next is egg white, which is divided into four balls.It contains a lot of protein, vitamins and minerals.In addition, there is a lysozyme - a special enzyme, has an antibacterial effect.Through protein layer can escape only gases.
Protein covered podskorlupovymi two balls between which there is a small gap.Shell eggs - very thick protective shell eggs, which consists mainly of calcium carbonate.Eggshell can have different thicknesses and colors - this is the characteristic features of each type.
structure of human eggs
female egg - a sex cell, which is stored and matured in the follicles of the ovary.Like all animals, human germ cell is designed to transmit a set of chromosomes during reproduction.
Unlike somatic, germ cells are produced by meiosis, so include only the haploid (in humans is 23) set of chromosomes.The structural features of human eggs will be described below.
first distinguishing feature - is the size.If the normal somatic cell rate rarely exceeds 20 mm, the diameter of the female egg is approximately 100 microns.This sex cell is fixed to the end of their maturation is in the follicle.
Thus, the structure of the egg is similar to other cells in the body - it consists of a nucleus, cytoplasm and plasma membrane is limited.As already stated, the haploid nucleus.The cytoplasm contains a huge amount of ribosomes, mitochondria, and the EPS.
also throughout the cell are evenly distributed so-called yolk granule cells that provide power until its introduction into the uterine wall.Yolk vesicles filled with nutrients - mainly small amount of fats and proteins, as well as vitamins and minerals.
structure of a woman's egg has some more features.For example, in the outer bowl of the cytoplasm containing special secretory granules.With the penetration of sperm into the granule contents is released and acts on the shell of the egg - as a result it changes its structure so that no other sperm can not penetrate therethrough.
interesting fact is that the number of eggs a woman has laid still in the embryonic stage of development.It was during the development of the ovaries in the fetus is already formed a certain number of follicles and eggs.When compared to the male body, the process of formation of spermatozoa, since puberty, it goes constantly.
As you can see, the structure of the egg is quite specific and is fully compliant of its functions.
