menstrual cycle

• Puberty is the period during which adolescents start to develop secondary sexual characteristics, such as facial hair in men and breasts in women, triggered by reproductive hormones.
• The menstrual cycle is a four-stage process involving the interaction of four hormones: estrogen, progesterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH).
• The average length of a menstrual cycle is around 28 days but it varies a lot between different people and that's perfectly healthy.
• Stage one of the menstrual cycle is known as menstruation, which is the period of bleeding that normally lasts about four days and is due to the breakdown of the uterus lining.
• Stage two of the menstrual cycle is when the uterus lining starts to build up again and becomes a thick spongy layer with lots of blood vessels in it, lasting around ten days up to day 14 and preparing the uterus lining for a fertilized egg.
• Ovulation, the third stage of the menstrual cycle, takes place in a single day and involves the egg being released from one of the ovaries.
• Stage four of the menstrual cycle, which stretches all the way to day 28, involves maintaining the lining of the uterus once we get to the end of the cycle.
• If no fertilized egg has made it to the uterus by the end of the cycle, the uterus lining would start to break down and the cycle would start again.
• If a fertilized egg does make it to the uterus, the cycle would stop because the woman is pregnant.
• The hormones responsible for the menstrual cycle are estrogen, which is produced in the ovaries and stimulates the uterus lining to grow, progesterone, which is also produced in the ovaries and maintains the lining of the uterus, luteinizing hormone (LH), which is produced in the pituitary gland and stimulates the release of an egg on day 14, and follicle stimulating hormone (FSH), which is also produced in the pituitary gland and stimulates the maturation of an egg in one of the ovaries.
• FSH stimulates the ovaries to produce estrogen, which is why we see higher levels of FSH just before estrogen starts to increase.
• LH stimulates the release of an egg on day 14, which is known as ovulation.
• Progesterone inhibits both LH and FSH, which is why we see higher levels of progesterone just before LH and FSH levels get high.