Biology Class 12 NCERT Solutions: Chapter 3 Human Reproduction Part 3 (For CBSE, ICSE, IAS, NET, NRA 2023)

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Q. 7 Name the hormones involved in regulation of spermatogenesis.

Answer:

  • Follicle-stimulating hormones (FSH) and luteinizing hormones (LH) are secreted by gonadotropin releasing hormones from the hypothalamus.
  • These hormones are involved in the regulation of the process of spermatogenesis. FSH acts on sertoli cells, whereas LH acts on leydig cells of the testis and stimulates the process of spermatogenesis

Q. 8 Define spermiogenesis and spermiation.

Answer:

  • Spermiogenesis:

It is the process of transforming spermatids into matured spermatozoa or sperms.

  • Spermiation:

It is the process when mature spermatozoa are released from the sertoli cells into the lumen of seminiferous tubules.

Q. 9 Draw a labeled diagram of sperm.

Answer:

Labeled Diagram of Sperm

Q. 10 What are the major components of seminal plasma?

Answer:

  • Semen (produced in males) is composed of sperms and seminal plasma. The major components of the seminal plasma in the male reproductive system are mucus, spermatozoa, and various secretions of accessory glands.
  • The seminal plasma is rich in fructose, calcium, ascorbic acid, and certain enzymes. It provides nourishment and protection to sperms.
  • Seminal fluid is the secretion of accessory sex glands of male (i.e.. , of seminal vesicles, prostate gland and Cowper՚s glands) . It is rich in fructose, calcium and certain enzymes

Q. 11 What are the major functions of male accessory ducts and glands?

Answer:

  • The male accessory ducts are vasa efferentia, epididymis, vas deferens, and rete testis. They play an important role in the transport and temporary storage of sperms.
  • On the contrary, male accessory glands are seminal vesicles, prostate glands, and bulbourethral glands.
  • These glands secrete fluids that lubricate the reproductive system and sperms. The sperms get dispersed in the fluid which makes their transportation into the female body easier.
  • The fluid is rich in fructose, ascorbic acid, and certain enzymes. They also provide nutrients and activate the sperm.