Chapter 3: Human Reproduction

Reproductive system is a collection of internal and external organs in both male and females that work together for purpose of producing a new generation of living organisms similar to their parents.

  • Reproduction ensure survival of species and transmission of genetic information from one generation to next.
  • Reproduction units are specialized cells called gametes, which are of two types: male gametes (spermatozoa or sperm) and female gametes (ova). These sex cells or gametes are formed in separate, paired organs of mesodermal origin, called gonads.
  • The gonads that produce male gametes or sperms are called testes, while those producing female gametes or ova are termed as ovaries.
  • Reproduction system of both the sex consists of organs which can be categorized into primary and secondary sex organs.
  • Organs which produce gametes or sex hormones are called primary sex organs. E.g. testis in male and ovaries in female.
  • Organs which neither produce gametes nor secrete sex hormones but perform important functions in reproduction are termed as secondary sex organs.
  • Secondary sex characters are external features which provide distinctiveness to the two sexes. They have no direct role in sexual reproduction.
  • The phenomenon when male and female individuals are differentiated externally is called sexual dimorphism.
  • Puberty is defined as the state at which the gonads come to maturity. These changes occurs in response to rising levels of gonadal hormones. It occurs sometime between 10 and 15 years.
  • Adolescence is the period between puberty and complete sexual maturity. Generally, it is considered to start with the development of secondary sexual characteristics and to end when physical growth of body slows down. In humans, age 11 to 20 years for boys and 10 to 18 years for girls is the adolescence period.

Humans are sexually reproducing and viviparous. The reproductive events in humans include:

  • Gametogenesis (Formation of gametes).
  • Insemination (Transfer of sperms into female genital tract).
  • Fertilization (Fusion of male and female gametes to form zygote)
  • Formation of blastocyst
  • Implantation (Attachment of blastocyst to uterine wall)
  • Gestation (Embryonic development)
  • Parturition (Delivery of the baby)


1. Male Reproductive System
2. Female Reproductive System
3. Gametogenesis
        (a) Spermatogenesis
        (b) Oogenesis
4. Menstrual Cycle
5.Fertilisation and Implantation

Dharmendra Gaur

Dharmendra Gaur (Msc. Zoology) aka DRGP. I love to learn and teach biology. By this blog I want to increase my knowledge and share my knowledge with others. Feel free to ask what ever you want to ask related to biology, I try my best to help you.

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