Human Reproduction

Human Reproduction

Every  organ  system  in  the  human body  works  continuously  to  maintain homeostasis for the survival of the individual. The human reproductive system is essential for the survival of the species. An individual may live a long healthy life without producing an offspring, but reproduction is inevitable for the existence of a species.

The reproductive system has four main functions namely,

·            to produce the gametes namely sperms and ova

·            to transport and sustain these gametes

·            to nurture the developing offspring

·            to produce hormones

The major reproductive events in human beings are as follows:

·            Gametogenesis: Formation of gametes by spermatogenesis and oogenesis.

·            Insemination: Transfer of sperms by the male into the female genital tract.

·            Fertilisation: Fusion of male and female gametes to form zygote, called fertilisation.

·            Cleavage: Rapid mitotic divisions of the zygote which convert the single celled zygote into a multicellular structure called blastocyst.

·            Implantation: Attachment of blastocyst to the uterine wall.

·            Placentation: Formation of placenta which is the intimate connection between foetus and uterine wall of the mother for exchange of nutrients.

·            Gastrulation: Process by which blastocyst is changed into a gastrula with three primary germ layers

·            Organogenesis: Formation of specific tissues, organs and organ systems from three germ layers.

·            Parturition: Expulsion of the foetus from the mother’s womb.

These functions are carried out by the primary and accessory reproductive organs. The primary reproductive organs namely the ovary and testis are responsible for producing the ova and sperms respectively. Hormones secreted by the pituitary gland and the gonads help in the development of the secondary sexual characteristics, maturation of the reproductive system and regulation of normal functioning of the reproductive system. The accessory organs help in transport and to sustain the gametes and to nurture the developing offspring.