What are the characteristics of the structure of male sex cells?
So, spermatozoa, in view of the fact that they must have high mobility for fertilization, are small cells, whose body is elongated. Sperm, in contrast to the ovum, does not have as much cytoplasm. It consists of a nucleus-containing part called a head, and a flagellum (tail), which is its organ of movement. From the so-called subcellular structures in the spermatozoon, there are mitochondria that supply it with the energy necessary for movement, the acrosomal vacuole (containing enzymes for dissolving the envelopes of a ripe egg), the proximal centriole. The total length of the spermatozoon is on average 60 μm, of which the tail is 55 μm.
When leaving the male sex gland, the testicle, sperm are immature, i.e. they do not have mobility, but are completely morphologically formed. Thus, they do not have the ability to fertilize. Activation of male sex cells occurs in the system of vas deferens.
What features of the structure are characteristic of the female germ cell?
The female germ cell, the egg, unlike the spermatozoon, is quite large in size and does not have mobility. Its dimensions reach 100-200 microns in humans. This is partly due to the fact that it is the egg that is the storage for trophic connections, which are simply necessary for the development of the embryo at the earliest stages. Also, a large number of cytoplasmic structures in its composition are needed for the formation of the very first generations of embryonic cells - blastomeres.
The egg cell, in contrast to the spermatozoon, is characterized by a large rounded nucleus, in which euchromatin (nucleoprotein localized closer to the center of the nucleus, more despilized, responsible for the transfer of genetic information) predominates and contains a large amount of cytoplasm. At the same time mitochondria in it are in less quantity, which is caused by low mobility of female sex cells. It is also worth noting that the human female sex cells do not exist isolated. The exception may be, perhaps, the earliest stage of their formation, at the stage of ogony. Usually, the ovules are in close connection with somatic cells, which, in fact, form a connecting and epithelial membrane around each sexual female cell. This complex was called the ovarian follicle. Its structure is complicated in the process of oogenesis .
All the differences of the egg from the sperm can not be placed in one table, so these are two different cells.
What are the main differences between germ cells?
Having told about what eggs are different from spermatozoa and why, summing up, I would like to list their main differences. Among them there are:
- chromosome set (in the spermatozoa - X chromosome, in the oocytes - U);
- different nuclear-cytoplasmic ratio (high in spermatozoon, low in egg);
- size and shape (large and rounded against small and elongated);
- the sperm has a movement organ.
Thus, it can be said that the main differences of the spermatozoon from the egg are in the structure, due to the biological value assigned to them.