Menstrual cycle
Read the following passage carefully and answer the given questions.
The reproductive cycle in the female primates is called menstrual cycle. The first menstruation begins at puberty and is called menarche. The cyclical changes in the ovary and the uterus during menstrual cycle are induced by changes in the levels of pituitary and ovarian hormones. One ovum is released during the middle of each menstrual cycle. The cycle starts with the menstrual phase, when menstrual flow occurs and it lasts for 3-5 days. Menstruation only occurs if the released ovum is not fertilised. Lack of menstruation may be indicative of pregnancy. 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. The secretion of gonadotropins 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. Rapid secretion of LH leading to its maximum level during the mid-cycle called LH surge which induces rupture of Graafian follicle and thereby the release of ovum. The ovulation is followed by the luteal phase.
Duration of menstrual phase is about:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 3-5 days
The passage says that the cycle starts with the menstrual phase, when menstrual flow occurs, and that it lasts for 3-5 days. A full menstrual cycle lasts about 28-29 days, and the menstrual phase is only its first part.
(1) 8-12 days — Incorrect. The menstrual phase is much shorter than this.
(2) 3-5 days — Correct. Menstrual flow lasts for 3-5 days.
(3) 20-25 days — Incorrect. This is close to the length of most of the cycle, not of the menstrual phase.
(4) 28-29 days — Incorrect. This is the average duration of the whole menstrual cycle, from one menstruation to the next.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.