The humans use sexual mode of reproduction. The organs associated with the process of reproduction in human males (men) and human females (women) are different, so the reproductive systems in males and females are different which are known as male reproductive system and female reproductive system, respectively.
The reproductive systems in human beings become functional (or start functioning) at a definite age called puberty. We will now describe the human male reproductive system and female reproductive system in detail, one by one.
The Male Reproductive System:
The human male reproductive system consists of the following organs : Testes, Scrotum, Epididymis, Vas deferens (or Sperm duct), Seminal vesicles, Prostrate gland and Penis. The human male reproductive system. Since the human male is called man, so we can also say that it is the reproductive system of man.
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Testes are the oval shaped organs which lie outside the abdominal cavity of a man. A man has two testes (singular of testes is testis). Testes are the primary reproductive organs in man (or males). The function of testes is to make the male sex cells (or male gametes) called sperms and also to make the male sex hormone called testosterone.
Please note that the testes of a man make the sex gametes (or sperms) from puberty onwards, throughout his life. The testes of a man lie in small muscular pouch called scrotum, outside the abdominal cavity.
The testes are outside the abdominal cavity of the body (and not deep inside the body), because the sperm formation requires a lower temperature than the normal body temperature. Being outside the abdominal cavity, the temperature of scrotum is about 3°C lower than the temperature inside the body. In this way, the testes provide an optimal temperature (most suitable temperature) for the formation of sperms.
The sperms formed in testes come out and go into a coiled tube called epididymis (see Figure 67). The sperms get stored temporarily in epididymis. From epididymis, the sperms are carried by a long tube called vas deferens (or sperm duct) which joins with another tube called urethra coming from the bladder.
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Along the path of vas deferens, the glands called seminal vesicles and prostrate gland add their secretions to sperms so that the sperms are now in a liquid. This liquid plus the sperms it contains is called semen (which is a thick liquid).
The secretions of seminal vesicles and prostrate gland provide nutrition to the sperms and also make their further transport easier. Urethra forms a common passage^ for sperms and urine.
Urethra carries the sperms to an organ called penis which opens outside the body. The penis passes the sperms from the man’s body into vagina in the woman’s body during mating for the purpose of reproduction. Please note that in man (or human male) there is only one opening for the urine and sperms to pass out of the body.
The Female Reproductive System :
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The human female reproductive system consists of the following organs: Ovaries, Oviducts (which are also called Fallopian tubes), Uterus, and Vagina. The human female reproductive system. Since the human female is called woman, so we can also say that it is the reproductive system of woman.
Ovaries are the oval shaped organs which are inside the abdominal cavity of a woman near the kidneys. A woman has two ovaries. Ovaries are the primary reproductive organs in a woman (or female).
The function of ovaries is to make mature female sex cells (or female gametes) called ‘ova’ or ‘eggs’, and also to make the female sex hormones (called oestrogen and progesterone). Each ovary is composed of several thousand follicles (which are a kind of unripe eggs or unripe ova). At puberty these follicles mature to form the ripe eggs or ripe ova (required for fertilisation).
Just above the ovaries are the tubes called oviducts (which are also known as fallopian tubes). The oviducts are not directly connected to ovaries but have funneled shaped openings which almost cover the ovaries. The ovum (or egg cell) released by an ovary goes into the oviduct through its funnel-shaped opening. The fertilisation of egg (or ovum) by a sperm takes place in the oviduct,
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The two oviducts connect to a bag like organ called uterus (or womb) at their other ends. The growth and development of a fertilised ovum (or fertilised egg) into a baby takes place in the uterus. The uterus is connected through a narrow opening called cervix to another tube called vagina which opens to the outside of the body.
Vagina receives the penis for putting sperms into the woman’s body. Vagina is a tubular structure. Vagina is also called ‘birth canal’ because it is through this passage that the baby is born after the completion of development inside the uterus of the mother. Please note that in woman (or human female) the opening for passing out urine (called urethra) and the vaginal opening are separate.
It is obvious from the above discussion that the female reproductive system in humans is more complex than that of the male reproductive system. The complexity in structure and function of the female reproductive system is necessary for the union of sperms and ovum (or eggs) inside the female body and the development of the baby in the mother’s uterus.
Fertilisation:
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In human beings, internal fertilisation takes place. The sperms (or male gametes) made in the testes of man are introduced into the vagina of the woman through penis during copulation (or mating). In this way, millions of sperms are released into the vagina at one time. The sperms are highly active and mobile (moving). The sperms move up through cervix into the uterus. From uterus, the sperms pass into the oviducts.
When the ovum (or egg) is fertilised in the oviduct, then a zygote is formed. The zygote divides rapidly by mitosis as it moves down slowly in the oviduct and forms a hollow ball of hundreds of cells. This hollow ball of cells, now called an embryo, sinks into the soft and thick lining of the uterus and gets embedded in it. The embedding of embryo in the thick lining of the uterus is called implantation.
After implantation, a disc-like special tissue develops between the uterus wall (called uterine wall) and the embryo (or foetus), which is called placenta (The foetus is connected to placenta in mother’s body through umbilical cord). It is through the placenta that all the requirements of the developing foetus like nutrition, respiration, and excretion, etc., are met from the mother’s body. In other words, the exchange of nutrients, oxygen and waste products between the embryo and the mother takes place through the placenta.
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The time period from the fertilisation up to the birth of the baby is called gestation. The average gestation period in humans (or the average duration of human pregnancy) is about nine months (or about 38 weeks).
During the gestation period, the foetus grows to become a baby. Birth begins when the strong muscles in the walls of the uterus start to contract rhythmically. The rhythmic contraction of uterus muscles gradually pushes the baby out of the mother’s body through vagina. This is how a baby is born. All of us were born from our mother in this way.