Question

Read the following graph and correlate the uterine events that take place according to the hormonal levels on
(i)6-15 days
(ii)16-25 days
(iii) 26-28 days (if the ovum is not fertilized)

• A. I-Degeneration of endometrium,
  II- Myometrium thickens, becomes vascularised, ready to receive and implant embryo,
  III- Regeneration of endometrium
• B. I-Degeneration of endometrium,
  II--Endometrium thickens, becomes vascularised, ready to receive and implant ovum,
  III- Regeneration of endometrium
• C. I-Degeneration of endometrium,
  II--Endometrium thickens, becomes vascularised, ready to receive and implant embryo,
  III- Regeneration of endometrium
• D. I-Regeneration of endometrium,
  II--Endometrium thickens, becomes vascularised, ready to receive and implant embryo,
  III- Degeneration of endometrium

Answer 1

The correct option is D I-Regeneration of endometrium,

II--Endometrium thickens, becomes vascularised, ready to receive and implant embryo,
III- Degeneration of endometrium

I) 6-15 days: It is the follicular phase where FSH stimulates ovarian follicles to secrete estrogen which in turn stimulates the proliferation of endometrium of uterine wall, which thickens.

II) 16-25 days: Secretion of progesterone maintains endometrium which is necessary for implantation of a fertilized ovum or other events of pregnancy.

III) 26-28 days: When fertilization does not take place, the endometrial lining disintegrates leading to menstruation and thus marking the new cycle.

Thus, the correct answer is

'I-Regeneration of the endometrium,

II--Endometrium thickens, becomes vascularized, ready to receive and implant embryo,

III- Degeneration of endometrium'.