Male reproduction system is made up of two separate parts,the one which is responsible for secreting male sexual hormone , and the other one that produces sperms . The major organs of the male reproductive system are the testes,the prostat,the seminal vesicles, the vas deferens , the epididymis and the penis. Male sexual hormone ) testosterone ) is secreted inside the testicle by the cells which are scattered through the seminiferous tubes,and also by known as Leydic cells. There are also other male hormones which are secreted by adrenal gland and have lesser power . These hormones cause masculine characteristics.
The part responsible for the production of sperm , produces male sexual cells or Spermatozoa . The internal wall of the seminiferous tubes is covered with a number of cells called Germ cells . After growing enough these cells develop into Spermatogonium. During the meiosis, cell division ) in which the number of chromosomes are decreased into half ) each of these cells are divided into four Spermatides,each of which contain twenty three chromosomes ) half of the chromosomes in non-reproductive cells (. Spermatides are then transformed into Spermatozoa. Each spermatozoon contains a round or enlongated head,body,and a long tail-like structure used for movement. The head carries genetic information of the father , and in case the sperm is mixed with ovum , this information along with the genetic information from the ovum are used to form the baby.A thin layer covers the head of spermatozoon . In this layer there are special enzyme system which help the process of sperm penetration into the ovum.
The spermatozoa,the secretions from the semen vesticle and the prostate gland altogether make the semen , which is a nourishing and suitable environment for sperms to live in. During the process of ejaculation spermatozoa which are suspended in the semen are come out of man's genital organ . These sperms do not have the reproductive ability immediately and must stay a few hours in women's genital system until they are ready for reproduction. This activation of sperms is called Capacitation.It should be mentioned that only sperms,but not the semen,enter the uterus and fallopian tubes.
The movement of spermatozoa inside the genital system of women happens throug two mechanisms :
1 - actively,hence with the help of it own tail movement spermatozoa can move a few millimeters forward in a minute.
2 - inactively , through the regular contraction of the muscles of the uterus. During every ejaculation a few milliliters of semen,containing millions of spermatozoa, leave man's genital organ . This number of spermatozoa is for the certainty of fertilization.
Spermatozoa usually retain their reproductive ability for twenty four hours . Although spermatozoa may remain active for a longer period,with time they gradually lose their ability for reproductivity ; and usually reproduction by old sperms is not possible and in case it happens unwelcomed consequences is to be expected during the formation of the offspring.