Question

Read the following statements about
menstrual cycle and select the correct
statements.
(i) Lack of menstruation may be indicative of pregnancy.
(ii) The changes in the ovary and the uterus
are induced by changes in the levels of
ovarian hormones only.
(iii) LH surge induces ovulation.
(iv) If fertilization occurs, corpus luteum
degenerates immediately.

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (i) and (iii)
• D. (ii) and (iv)

Answer 1

The correct option is C (i) and (iii)

The process of shedding of the endometrial wall that leads to vaginal bleeding is called menstruation. If fertilisation occurs then the menstrual cycle would be paused during the gestation period. Thus lack of menstruation may indicate pregnancy.

The increase in the levels of luteinizing hormone is called LH surge. The surge results in the rupture of the graafian follicle to release the secondary oocyte. This is called ovulation. Thus LH surge results in ovulation.

The changes in the ovary and uterus are induced by the changes in the levels of not only ovarian but also pituitary hormones (FSH and LH).

Corpus luteum is essential for the establishment of pregnancy. It secretes progesterone hormone which maintains endometrium. The endometrium is essential for implantation of the fertilised egg. Hence corpus luteum does not degenerate if fertilization occurs.

In the absence of fertilisation, the corpus luteum degenerates.