Read the given passage and answer the following questions:
The menstrual cycle starts with the menstrual phase, when menstrual flow occurs and it lasts for 3-5 days. The menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels which forms liquid that comes out through vagina. Menstruation only occurs if the released ovum is not fertilised. Lack of menstruation may be indicative of pregnancy. However, it may also be caused due to some other underlying causes like stress, poor health etc. The menstrual phase is followed by the follicular phase. During this phase, the primary follicles in the ovary grow to become a fully mature Graafian follicle and simultaneously the endometrium of uterus regenerates through proliferation. These changes in the ovary and the uterus are induced by changes in the levels of pituitary and ovarian hormones. The secretion of gonadotropins (LH and FSH) increases gradually during the follicular phase, and stimulates follicular development as well as secretion of estrogens by the growing follicles. Both LH and FSH attain a peak level in the middle of cycle (about 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle called LH surge induces rupture of Graafian follicle and thereby the release of ovum (ovulation). The ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle transform as the corpus luteum . The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium.
Given below are two statements:
Statement I: During pregnancy all events of the menstrual cycle stop and there is no menstruation.
Statement II: Cyclic menstruation is an indicator of the normal reproductive phase and extends between puberty and menarche.
In the light of the above statements, choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Statement I is true but Statement II is false.
Menarche is the first menstruation, at puberty. Menopause is the end of menstrual cycles, at about 50 years of age. The years in between are the normal reproductive phase of a woman.
Statement I: During pregnancy all events of the menstrual cycle stop and there is no menstruation. — True. The endometrium kept up by the corpus luteum is needed for implantation and the other events of pregnancy. So during pregnancy the cycle stops and there is no menstruation.
Statement II: Cyclic menstruation is an indicator of the normal reproductive phase and extends between puberty and menarche. — False. Menarche itself happens at puberty, so there is no span of cycles between the two. The reproductive phase extends from menarche to menopause.
NCERT Extract:
Menstrual Cycle – “… The first menstruation begins at puberty and is called menarche.”
Menstrual Cycle – “… During pregnancy all events of the menstrual cycle stop and there is no menstruation. In the absence of fertilisation, the corpus luteum degenerates. This causes disintegration of the endometrium leading to menstruation, marking a new cycle. In human beings, menstrual cycles ceases around 50 years of age; that is termed as menopause. Cyclic menstruation is an indicator of normal reproductive phase and extends between menarche and menopause.”