Question

Refer to the given schematic representation of menstrual cycle showing three phases I, II and Ill.

Select the option that correctly matches these phases with the following events.

(i) FSH secreted by the anterior pituitary stimulates the ovarian follicle to secrete estrogen which stimulates the proliferation of the endometrium.

(ii) LH secreted by the anterior pituitary stimulates the development of corpus luteum which secretes progesterone.

(iii) Reduced production of LH from anterior pituitary causes degeneration of corpus luteum, thereby progesterone production is reduced.

• A. Phase I - (i); Phase II - (ii), Phase III - (iii)
• B. Phase I - (iii); Phase II - (i), Phase III - (ii)
• C. Phase I - (ii); Phase II - (iii), Phase III - (i)
• D. Phase I - (iii); Phase II - (ii), Phase III - (i)

Answer 1

The correct option is C Phase I - (ii); Phase II - (iii), Phase III - (i)

Option C is correct because,

• Phase 1 shows Luteal Phase (Secretary Phase) which begins from day 15 to 28 in a 28-day cycle. in this phase Corpus luteum secrets progesterone. Endometrium thickens and uterine glands become secretory.
• Phase 2 shows Menstrual Phase which begins from day 1 to 5 in a 28-day cycle. In this phase Progesterone production is reduced. In fact, menstrual flow is associated with the withdrawal of progesterone.
  
• Phase 3 shows Follicular phase (Proliferative phase) which begins from day 6 to 14 in a 28-day cycle. in this phase Endometrium rebuilds, FSH secretion and estrogen secretion increase.