In this blog, we will learn about reproduction in human beings. During sexual intercourse, male sperms enter the female body through the vaginal passage. They travel upwards and reach the oviduct where they may encounter the egg. The fusion of male and female gametes to form a zygote is called fertilization.

The fertilized egg, the zygote, gets implanted in the lining of the uterus and starts dividing. Hence the uterus prepares itself every month to receive and nurture the growing embryo.

The lining thickens and is richly supplied with blood to nourish the growing embryo. The embryo gets nutrition from the mother�s blood with the help of a special tissue called the placenta. The placenta is a disc that is embedded in the uterine wall. It contains villi on the embryo�s side of the tissue.

On the mother�s side are blood spaces, which surround the villi. This provides a large surface area for glucose and oxygen to pass from the mother to the embryo. The developing embryo will also generate waste substances that can be removed by transferring them into the mother�s blood through the placenta. The development of the child inside the mother�s body takes approximately nine months. The child is born as a result of rhythmic contractions of the muscles in the uterus.

Let's discuss the male and female reproductive system and their roles in reproduction in human beings.

Male reproductive system

The human male reproductive system consists of the following organs:-

1. Testes
2. Scrotum
3. Vas deferens
4. Urethra
5. Penis

The formation of germ cells/sperms takes place in the testes. Testes are located outside the abdominal cavity in the scrotum because sperm formation requires a lower temperature than the normal body temperature. The sperms are tiny bodies that consist of mainly genetic material and a long tail that helps them to move towards the female germ cell.

The sperms formed are delivered through the vas deferens which unite with a tube coming from the urinary bladder. Along the path of the vas deferens, glands like the prostate and the seminal vesicles add their secretions so that the sperms are now in a fluid that makes their transport easier and this fluid also provides nutrition.

Female reproduction system

The female reproduction system is more complex as compared to that of the male reproductive system. The female reproductive system consists of the following organs.

1. Ovaries
2. Fallopian tube
3. Uterus
4. Vagina
5. The female germ cells are called eggs.

When a girl is born, the ovaries already contain thousands of immature eggs. On reaching puberty, some of these eggs start maturing. One egg is produced every month by one of these ovaries. The egg is then carried from the ovary to the womb through a thin oviduct or fallopian tube. The two oviducts unite into an elastic bag-like structure known as the uterus. The uterus opens into the vagina through the cervix.

Development of Embryo in Human

Let's discuss various stages of the development of an embryo. Once the male and female gamete i.e. sperm and ova fuses, fertilization occurs and a zygote is formed inside the oviduct. Then this zygote divides repeatedly to give rise to a ball of cells. The cells then begin to form groups that develop into different tissues and organs of the body. This developing structure is termed an Embryo.

The embryo then embeds itself on the wall of the uterus. This process is called implantation. The embryo continues to develop in the uterus. It gradually develops body parts such as hands, legs, head, eyes, ears, etc.

The stage of the embryo in which all the body parts can be identified distinctly is called a fetus. When the development of the fetus is complete the mother gives birth to the baby. The birth of a fully developed fetus is called parturition.

Read More: Reproductive Health And Adolescence: Reproduction In Animals