Biology Class 12 NCERT Solutions: Chapter 3 Human Reproduction Part 5

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Q.15 Name the functions of the following.

(a) Corpus luteum

(b) Endometrium

(c) Acrosome

(d) Sperm tail

(e) Fimbriae

Answer:

(a) Corpus luteum –

  • Corpus luteum is formed from the ruptured Graafian follicle. It secretes progesterone hormone during the luteal phase of the menstrual cycle.

  • A high level of progesterone inhibits the secretions of FSH and LH, thereby preventing ovulation.

  • It also allows the endometrium of the uterus to proliferate and to prepare itself for implantation.

(b) Endometrium –

  • It is the innermost lining of the uterus. It is rich in glands and undergoes cyclic changes during various phases of the menstrual cycle to prepare itself for the implantation of the embryo.

(c) Acrosome –

  • It is a cap-like structure present in the anterior part of the head of the sperm.

  • It contains hyaluronidase enzyme, which hydrolyses the outer membrane of the egg, thereby helping the sperm to penetrate the egg at the time of fertilization.

(d) Sperm tail –

  • It is the longest region of the sperm that facilitates the movement of the sperm inside the female reproductive tract.

(e) Fimbriae –

  • They are finger-like projections at the ovarian end of the fallopian tube. They help in the collection of the ovum (after ovulation), which is facilitated by the beating of the cilia.

Q.16 Identify True/ False statement. Correct each false statement to make it true.

(a) Androgens are produced by Sertoli cells. (True/False)

Answer: Androgens are produced by Sertoli cells. (False)

  • Androgens are produced by Leydig cells found in seminiferous tubules of the testis.

(b) Spermatozoa get nutrition from Sertoli cells. (True/False)

Answer: Spermatozoa get nutrition from Sertoli cells. (True)

(c) Lesydig cells are found in ovary. (True/False)

Answer: Leydig cells are found in ovary. (False)

  • Leydig cells are found in the seminiferous tubules of the testis.

(d) Leydig cells synthesise androgens. (True/False)

Answer: Leydig cells synthesise androgens. (True)

(e) Oogenesis takes place in corpus luteum. (True/False)

Answer: Oogenesis takes place in corpus luteum. (False)

  • Oogenesis takes place in the ovary.

(f) Menstrual cycle ceases during pregnancy. (True/False)

Answer: Menstrual cycle ceases during pregnancy. (True)

(g) Presence or absence of hymen is not a reliable indicator of virginity or sexual experience. (True/False)

Answer: Presence or absence of the hymen is not a reliable indicator of virginity or sexual experience. (True)

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