Important Questions for Class 12 Chapter 3 - Human Reproduction

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Important questions based on NCERT syllabus for Chapter 3 - Human Reproduction:

Question-1: Write two major functions each of testis and ovary.

Solution: Testes – Testes are the primary sexual organs in male. Two major functions of testes are –
(i) Testosterone production from leydig cells. (ii) Production of sperm cells in seminiferous tubules.
Ovary – Ovaries are the primary female sex organs. Two main functions of ovaries are
(i) Productions of female germ cells called eggs or oocytes.
(ii)Production of hormones – estrogens & progesterone which affect many of the female secondary sexual characters & reproductive functions.

Question-2: Describe the structure of a seminiferous tubule.

Solution: The seminiferous tubule is a structural unit in the adult testis. The seminiferous tubules are situated in testicular lobules. Seminiferous tubule consists of two types of cells – Sertoli or supporting cells & spermatogenic cellsl Sertoli cells, are elongated and pyramidal & partially envelop the spermatogenic cells. The cells provide nourishment to the developing spermatogenic cells. Spermatogenic cells are stacked in 4-8 layers. These cells divide several times & differentiate to produce spermatozoa. Between seminiferous tubules lie the interstitial cells or leydig cells which produces testosterone hormone.

Question-3: Name the hormones involved in regulation of spermatogenesis.

Solution: After sexual maturity, spermatogenesis starts due to the secretion of gonadotropin releasing hormone (GnRH) from the hypothalamus of brain. GnRH acts on pituitary gland and stimulates secretion of luteinizing hormone (LH) and follicle stimulating hormone (FSH). LH induce the Leydig’s cells of the testis to produce male sex hormones called androgens. High level of androgens stimulate the process of spermatogenesis. FSH acts on the Sertoli cells and stimulates secretion of some factors which help in the process of spermiogenesis.