Ovarian Cycle

• Menstrual Cycle (Ovarian Cycle)

  1. Follicular phase

  2. Ovulation

  3. Luteal phase
• Ovarian cycle


  The series of physiological events that occur within the ovaries (ovulation) and the subsequent transformation of the ovarian follicles
• Ovarian cycle


  • Regulated by complex interactions between hormones produced by the hypothalamus, pituitary gland, and ovaries
  • Coordinated with the menstrual cycle, which involves changes in the uterus lining in preparation for possible implantation of a fertilized egg
• Follicular Phase


  1. Begins on the first day of menstruation

  2. Lasts for approximately 10 to 14 days

  3. Several follicles within the ovaries start to develop under the influence of follicle-stimulating hormone (FSH) secreted by the pituitary gland

  4. One dominant follicle continues to develop and mature, while others undergo atresia (degeneration)

  5. Follicles produce increasing levels of estrogen, which stimulates the thickening of the uterine lining (endometrium) in preparation for potential implantation

  6. Estrogen inhibits the release of follicle-stimulating hormone (FSH), maintaining the dominance of the selected follicle

  7. As the follicular phase progresses, estrogen levels rise, causing a negative feedback on the pituitary gland and hypothalamus, which prevents the release of further FSH
• Ovulation


  1. Midway through the ovarian cycle, usually around day 14

  2. A surge of luteinizing hormone (LH) is released from the pituitary gland

  3. LH surge triggers the release of the mature egg from the dominant follicle

  4. The egg is swept into the fallopian tube, where it awaits fertilization by sperm

  5. Ovulation is typically accompanied by a slight increase in basal body temperature and a change in cervical mucus consistency
• Luteal Phase


  1. Following ovulation, the ruptured follicle transforms into a structure called the corpus luteum

  2. The corpus luteum secretes progesterone, which prepares the endometrium for possible implantation by further thickening it and increasing its blood supply

  3. Progesterone also inhibits the release of LH and FSH, preventing the development of additional follicles

  4. If fertilization and implantation do not occur, the corpus luteum begins to degenerate around day 22 of the cycle

  5. As progesterone levels decline, the endometrium is no longer maintained, leading to the shedding of the uterine lining and the onset of menstruation

  6. The length of the ovarian cycle can vary from woman to woman but is typically around 28 days
• The menstrual cycle involves the follicular development, ovulation, and luteal phase