Question

What are the phases in the Menstrual cycle?

Answer 1

Menstrual Cycle:

1. The menstrual cycle is the female reproductive cycle that is marked by cyclic changes in the uterine lining. Gonadotropin hormones released by the anterior pituitary govern the menstrual cycle.
2. This cycle is 28 days long.
3. The menstrual cycle is broken down into four stages:
   1. Menstrual phase:
      1. Luteinizing hormone synthesis from the anterior lobe of the pituitary gland is diminished during this phase.
      2. This causes the Corpus luteum to degenerate, as well as a reduction in progesterone and estrogen production.
      3. Menstruation begins when the androecium of the uterus breaks, and the menstrual flow is made up of endometrial secretion, blood, and unfertilized ovum.
   2. Follicular phase:
      1. The initial follicles in the ovary mature into fully grown graafian follicles during this period.
      2. Pituitary and ovarian hormone changes cause the graafian follicle to develop and the endometrium to regenerate..
      3. During this phase, the release of gonadotropins such as luteinizing hormone and follicular stimulating hormone steadily increases, encouraging follicular development as well as oestrogen secretion by the expanding follicles.
   3. Ovulatory phase:
      1. In the middle of the cycle, around the 14th day, both LH and FSH reach a high level.
      2. The rapid secretion of LH, which peaks in the mid-cycle and is known as the LH surge, causes the rupture of the Graafian follicle and, as a result, the release of ovum, which is known as ovulation.
   4. Luteal phase:
      1. The ruptured section of the Graafian follicle turns into a yellow body known as the Corpus luteum during this phase.
      2. The corpus luteum secretes a lot of progesterone hormone, which keeps the endometrium healthy and ready for the fertilised ovum to implant.
      3. During pregnancy, all menstrual cycle events cease and there is no menstruation. In the absence of fertilisation, the corpus luteum degenerates, causing the endometrium to disintegrate, resulting in menstruation and the start of a new cycle.