Why does menstruation occur?

AcademicBiologyNCERTClass 10

Menstruation, also known as a period or monthly, is the normal and regular discharge of blood and mucosal tissue. It occurs due to the rupture or removal of the inner, thick, and soft lining of the uterus through the vagina when fertilization does not take place.

The menstrual cycle  in human females (or women) is as follows:
  • A female, after attaining puberty, every month one of the ova in the ovaries matures and gets released, once every 28 days, by the process of ovulation.
  • The lining of the uterus becomes thick and spongy before ovulation in order to receive the fertilized egg. If the egg is not fertilized, this lining of the uterus or womb breaks and sheds its lining and passes out of the body through the vagina in the form of blood and tissue, this flow of tissue and blood from the vagina is known as menstrual flow.
  • This occurs on the 14th day of ovulation and usually lasts from 3-5 days.
  • After this flow stops, the uterus starts preparing itself for the fertilized egg. If it does not receive the fertilized egg, the same set of events is repeated.
Menstruation or Periods normally start between ages 11 and 14 and continue until menopause at about age 51.

Common symptoms and signs of this cycle include acne, bloating, sore breasts, feeling tired, food cravings, mood changes, irritability, lower back pain, headache, and fatigue.
Updated on 10-Oct-2022 13:19:08