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.
Corpus luteum secretes -
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Progesterone
The passage ends with the luteal phase, which follows ovulation. In this phase, the remaining parts of the Graafian follicle change into the corpus luteum. The corpus luteum secretes large amounts of progesterone. Progesterone keeps the endometrium (the lining of the uterus) ready for the implantation of the fertilised ovum and for pregnancy.
(1) Testosterone — Incorrect. Testosterone is a male hormone (an androgen) made by the Leydig cells of the testis.
(2) Estrogen — Incorrect. In the menstrual cycle, estrogens are secreted mainly by the growing follicles during the follicular phase.
(3) Relaxin — Incorrect. Relaxin is secreted by the ovary only in the later phase of pregnancy. It is not the hormone of the corpus luteum in the menstrual cycle.
(4) Progesterone — Correct. Progesterone from the corpus luteum is essential for the maintenance of the endometrium.
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.
NCERT Extract:
Menstrual Cycle – …
