Human Reproduction Class 12 Notes

Reproduction is the process of giving birth to their young ones which are identical to their parents. As we all are aware of, the process of reproduction in humans is sexual reproduction, which involves internal fertilization by sexual intercourse.

Human Reproductive System

The Human Reproductive System mainly consists of:

The Male Reproductive System

Male reproductive system

  • The male reproductive system is positioned in the pelvis region and comprises a pair of testes in addition to the accessory glands, ducts, and the external genitalia.
  • A pouch-like structure known as scrotum encloses the testes located outside the abdominal cavity
  • Each testis has close to 250 testicular lobules(compartments). These lobules comprise 1-3 seminiferous tubules wherein the sperms are produced. the lining of these tubules consists of two types of cells – male germ cells and sertoli cells
  • The exterior of these tubules consist of spaces containing blood vessels and Leydig cells
  • Male sex accessory ducts comprises rete testis, vasa efferntia, epididymis and vas deferens
  • The urethra opens externally to the urethral meatus
  • The male external genitalia, the penis is covered by foreskin which is a loose fold of skin

The Female Reproductive System

Female Reproductive Organs

The female reproductive system is made up of the internal and external sex organs, which consists of a pair of ovaries and oviducts, cervix, uterus, vagina and the external genitalia situated in the pelvic region. Along with the mammary glands, these female reproductive organs are combined both structurally and functionally in order to support the complete processes of reproduction including ovulation, fertilization, pregnancy, and the birth of a child.

  • The female accessory ducts are constituted by the oviducts, vagina and uterus
  • The section closer to the ovary is funnel-shaped infundibulum that possesses the fimbriae – finger-like projections facilitating the assimilation of ovum post ovulation
  • The infundibulum directs to a wider section of oviduct known as ampulla.
  • The last section of the oviduct, isthmus, has a narrow lumen joining the uterus
  • Uterus is also known as the womb
  • The cervical cavity is known as the cervical canal which goes onto form the birth canal along with the vagina
  • Female external genitalia comprises – mons pubis, labia minora, labia majora, clitoris and hymen

Both the male and female reproductive systems play an important role in the process of reproduction. Other than these reproductive organs, there are sex hormones which are produced by the respective glands and are mainly involved in the development of secondary sexual characteristics and proper functioning of the reproductive tracts.

Further Reading: Important Questions for Class 12 Chapter 3: Human Reproduction

Process of Reproduction

The process of reproduction in all humans are carried out phase-wise as discussed below:

  • Pre-fertilization – Gametes are formed and transferred
  • Fertilization- formation of zygote after a sperm fertilizes the egg
  • Post-fertilization- Mitotic division of zygote leading to the formation of an embryo. This reproductive stage is referred to as embryogenesis.

Duration and Stages of Pregnancy

Human gestation lasts for an average of 266 days or 38 weeks or 9 months and these intervals are called as trimesters.

  • 1st trimester (1st 3 months or week 1 – 12) – pre embryonic and embryonic development.
  • 2nd trimester (next 3 months: week 13 – 24) – The fetal development begins.
  • 3rd trimester (next 3 months: week 25 – birth) – At this stage baby continues to grow and mature.

Also See: Menstrual Cycle: Tears of Uterus

Few Important Questions

  • What are the three stages of parturition?
  • What happens during spermatogenesis?
  • Describe the structure of a male reproductive system?
  • What is the role of sex hormones in the human reproductive system?
  • Explain in detail about the female reproductive system with a neat labelled diagram?

Learn more about human reproduction from the topics given below:

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