Read the passage and answer the following questions:
The major events of the 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.
Which of the following secretes large amounts of progesterone?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Corpus luteum
Several glands and structures secrete hormones during the menstrual cycle, and each one has its own hormone. After ovulation, the remaining parts of the Graafian follicle change into the corpus luteum in the luteal phase.
Option (1) Graafian follicle — Incorrect. The growing follicles, including the Graafian follicle, secrete estrogens during the follicular phase. The large amount of progesterone comes later, from the corpus luteum.
Option (2) Corpus luteum — Correct. The corpus luteum secretes large amounts of progesterone, which is essential for the maintenance of the endometrium.
Option (3) Anterior pituitary — Incorrect. The anterior pituitary secretes the gonadotropins LH (luteinising hormone) and FSH (follicle stimulating hormone), which control the ovary. It does not secrete progesterone.
Option (4) Hypothalamus — Incorrect. The hypothalamus secretes GnRH (gonadotropin releasing hormone), which acts on the anterior pituitary, not progesterone.
NCERT Extract:
Menstrual Cycle – “… 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.”
Menstrual Cycle – “… The ovulation (ovulatory phase) is followed by the luteal phase during which the remaining parts of the Graafian follicle transform as the corpus luteum (Figure 2.9). The corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium. Such an endometrium is necessary for implantation of the fertilised ovum and other events of pregnancy.”