Ovarian cycle-Menstrual Cycle

Ovarian cycle (Menstrual cycle)

  • It is a series of cyclic changes occurring in the reproductive tract of female with the periodicity of 28 days
  • It is also known as menstrual cycle,
  • also known as endometrial cycle
  • It occur From puberty to menopause
  • It is characterized by loss of vaginal blood (breaking of endometrium wall of uterus)
  • The cycle is under Influenced of hormones secreted by pituitary gland (FSH and LH), and ovary (progesterone and oesterogen).

Complete in 3 phase

  1. Menstrual phase
  2. Proliferative phase or follicular or ovulatory phase
  3. Luteal or secretory phase

Figure: Menstrual cycle

Menstrual phase

  • This phase is characterized by discharge of blood, connective tissues and mucus due to cast off of epithelial lining of endometrium wall
  • It Lasts for 3-5 days
  • Ovum remain unfertilized,
  • At this time level of oestrogen and progesterone is very low in blood resulting in Breaking of endometrium wall of uterus
  • About 50-100 ml blood with mucus are discharges as menstrual flow.

Proliferative phase

  • This phase is characterized by rapid proliferation and repair of damaged endometrium wall
  • It Lasts for 9-10 days (5th – 14thdays)
  • Anterior pituitary gland release Follicular stimulating Hormone (FSH) which stimulates development and maturation of grafian follicle. So, it is also known as Follicular Phase.
  • Mature grafian follicle secrete oestrogen. Its level gradually increases and maximize at 12thday
  • Oestrogen stimulate endometrium repair and proliferation. It also stimulate Ovulation
  • Endometrium become 2-3 mm thick and highly vascular

Luteal phase

  • This phase is characterized by release of Ovum from mature graffian follicle which is stimulated by the secretion of luteinizing hormone (LH) by pituitary gland.
  • It Lasts for 12-14 days (14th-28th┬áday)
  • LH along with FSH stimulate ovulation.
  • Mature graffian follicle release ovum and the rapture follicular cell form corpus luteum
  • Corpus luteum secrete progesterone, high level of progesterone inhibit maturation of any other follicles
  • Progesterone also stimulate thickening of endometrium wall
  • When ovum remain unfertilized, corpus luteum degenerate; level of both hormone (progesterone and oestrogen) decreases, causing breaking of endometrium wall continuing the menstrual phase.