Menstrual cycle:
- It is found only in primate females.
- Its duration is 28 to 30 days in a woman and 35 days in the chimpanzee.
- In woman, the menstrual cycle begins at an age of 12 years which is called menarche.
- The menstrual cycle ceases naturally at an age of 45 to 50 years which is called menopause.
The menstrual phase has 4 phases of viz:
- Menstrual phase
- Follicular phase or Proliferative phase
- Ovulatory phase or recovery phase
- Luteal phase or secretory phase