NCERT Class 12 Biology Biology: Chapter 2 — HUMAN REPRODUCTION
Chapter 2 of the NCERT Class 12 Biology textbook, titled 'Human Reproduction', details the biological processes involved in human reproduction. It begins by outlining the key reproductive events: gametogenesis (sperm and ovum formation), insemination (sperm transfer), fertilisation (gamete fusion), implantation (blastocyst attachment), embryonic development, and parturition (childbirth). The chapter highlights the differences in reproductive timelines between males and females, such as continuous sperm production in men versus the cessation of ovum formation around age fifty in women. It then delves into the male reproductive system, describing its components like testes, scrotum, seminiferous tubules, Sertoli cells, Leydig cells, and accessory ducts, explaining their roles in sperm production and hormone synthesis. This chapter provides a foundational understanding of human reproductive biology crucial for CBSE curriculum.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 12 |
| Subject | Biology |
| Book | Biology |
| Chapter | Chapter 2 — HUMAN REPRODUCTION |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 517 |
Learning outcomes
- Identify and describe the components of the male reproductive system.
- Explain the process of spermatogenesis and the role of Sertoli and Leydig cells.
- Understand the sequence of reproductive events in humans.
- Differentiate between male and female reproductive timelines.
Vocabulary
| Word | Meaning |
|---|---|
| Viviparous | Giving birth to live young. |
| Gametogenesis | The process of formation of gametes (sperms and ova). |
| Insemination | Transfer of sperms into the female genital tract. |
| Fertilisation | Fusion of male and female gametes to form a zygote. |
| Blastocyst | An early stage of embryonic development. |
| Implantation | Attachment of the blastocyst to the uterine wall. |
| Gestation | Embryonic development within the uterus. |
| Parturition | The delivery of a baby. |
| Spermatogenesis | The process of sperm formation. |
| Scrotum | A pouch that holds the testes outside the abdominal cavity. |
| Seminiferous tubules | Tubes within the testes where sperm are produced. |
| Sertoli cells | Cells in seminiferous tubules that nourish germ cells. |
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Practice questions
- What is the primary function of the scrotum? Answer: The scrotum helps maintain a low temperature (2-2.5°C lower than normal body temperature) necessary for spermatogenesis.
- Name the cells that provide nutrition to the germ cells in the seminiferous tubules. Answer: Sertoli cells provide nutrition to the germ cells.
- What are Leydig cells and what do they secrete? Answer: Leydig cells are interstitial cells found in the interstitial spaces outside the seminiferous tubules. They synthesise and secrete testicular hormones called androgens.
- List the male sex accessory ducts in order. Answer: Rete testis, vasa efferentia, epididymis, and vas deferens.
Practice MCQs
Q1. Which of the following is NOT a reproductive event in humans?
Explanation: Digestion is a metabolic process, not a reproductive event. Gametogenesis, insemination, and parturition are key stages in human reproduction.
Q2. The scrotum helps in maintaining the temperature of the testes for:
Explanation: The scrotum maintains a temperature 2-2.5°C lower than the normal internal body temperature, which is optimal for spermatogenesis.
Q3. Which cells in the seminiferous tubules are responsible for producing sperms?
Explanation: Male germ cells (spermatogonia) undergo meiotic divisions to produce sperms, while Sertoli cells provide nutrition.
Q4. The vasa efferentia leave the testis and open into:
Explanation: The vasa efferentia collect sperm from the rete testis and transport them to the epididymis, located on the posterior surface of the testis.
Q5. Leydig cells are found in which part of the male reproductive system and what do they produce?
Explanation: Leydig cells, also known as interstitial cells, are located in the interstitial spaces outside the seminiferous tubules and produce androgens.
Frequently asked questions
What are the main stages of human reproduction?
The main stages are gametogenesis, insemination, fertilisation, implantation, embryonic development, gestation, and parturition.
Why is the scrotum important for male reproduction?
The scrotum maintains the testes at a temperature 2-2.5°C lower than the normal body temperature, which is essential for spermatogenesis.
What is the function of Sertoli cells?
Sertoli cells are located in the seminiferous tubules and provide nutrition to the developing germ cells during spermatogenesis.
What are androgens and where are they produced?
Androgens are male sex hormones, primarily testosterone, synthesised and secreted by Leydig cells found in the interstitial spaces of the testes.
Trace the path of sperm from the seminiferous tubules to the outside.
Seminiferous tubules → Rete testis → Vasa efferentia → Epididymis → Vas deferens → Urethra → Urethral meatus.
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NCERT Class 12 Biology — Biology — Chapter 2 — HUMAN REPRODUCTION. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.