Menstrual Cycle

• Puberty


  The period during which adolescents start to develop secondary sexual characteristics
• Secondary sexual characteristics


  • Facial hair in men
  • Breasts in women
• Reproductive hormones


  Hormones that trigger the development of secondary sexual characteristics
• Testosterone


  Hormone produced in the testes that stimulates sperm production in men
• Estrogen


  Hormone produced by the ovaries in women
• Menstrual cycle


  1. Menstruation

  2. Uterus lining building up

  3. Ovulation

  4. Maintaining uterus lining
• Uterus


  The organ in the female reproductive system where a fertilized egg implants and develops
• Fallopian tubes


  Tubes that connect the ovaries to the uterus, where eggs travel after ovulation
• The average length of a menstrual cycle is around 28 days but it varies a lot between different people
• Menstruation


  Breakdown of the uterus lining, resulting in bleeding
• Uterus lining building up


  Uterus lining becomes thick and spongy with blood vessels, preparing for a fertilized egg
• Ovulation


  Release of an egg from one of the ovaries
• Maintaining uterus lining


  Uterus lining is maintained if a fertilized egg implants, otherwise it breaks down and the cycle repeats
• Estrogen


  Hormone that stimulates the growth of the uterus lining
• Progesterone


  Hormone that maintains the uterus lining
• Luteinizing hormone (LH)


  Hormone that stimulates the release of the egg during ovulation
• Follicle stimulating hormone (FSH)


  Hormone that stimulates the maturation of an egg in the ovaries
• FSH stimulates the ovaries to produce estrogen


  As estrogen levels increase, they start to inhibit FSH (negative feedback)
• High estrogen levels


  Stimulate the release of LH, causing ovulation
• Progesterone


  Inhibits both LH and FSH