Prenatal Care

Conception is really a kind of a miracle. Nature created a number of complicated mechanisms, the structure of spermatozoon and ovule is marvelous.

Spermatozoon – male cell – has a head containing 23 chromosomes – genetic material, which together with the chromosomes of the woman makes the genome of a human being. The spermatozoon has ferments which help it to get into the ovule, the neck of the spermatozoon is a kind of an energy source, the tail helps it move. Its speed is 1,5 cm per minute. Spermatozoa live 4-5 days.

An ovule is a large and immobile cell. Its size is about 0,1 mm. It contains 23 chromosomes and number of ferments which help is live 3-4 days without other sources of nutrition. The ovule has a number of coats. The life of the ovule is about 24 hours.

After the sperm gets into the vagina, the uterus helps the spermatozoa – after 30-60 minutes the spermatozoa are in the uterus, in 1,5 – 2 hours – near the ovule.

The ovule secretes special substances helping spermatozoa find it. When they find the ovule, they fix on its surface and start turning it round – thus the surface of the ovule becomes thinner. In addition spermatozoa have ferments helping make holes in the surface – as a results one of the spermatozoa gets inside of the ovule. After that the ovule becomes inaccessible for other spermatozoa.

Sometimes two ovules appear in the same period – they both can meet spermatozoa – in such cases a woman gives birth to hetero-ovular twins. Monoovular twins are born in case the zygote divides into two parts. The genes of such twins are absolutely similar.

An ovule always contains only Х-chromosome (it determines the sex of the child), spermatozoa can be of two types – with either Х or Y  chromosome. In case the zygote contains XX chromosomes, the woman gives birth to a girl, if XY – a boy.  

Zhanna Smirnova, Pediatrician.