MENSTRUAL CYCLE

• Females are born with all the egg cells they will ever have.
• Terms for menstruation


  • Period
  • The Curse
  • Monthly Bleeding
• Menstrual cycle


  Regular changes in the activity of the ovaries and the endometrium that make reproduction possible
• Stages of menstrual cycle

  1. Enumerate and describe the stages of menstrual cycle using a diagram

  2. Explain the effect of hormones and its negative feedback in menstrual cycle
• Ovaries


  Female gonads that produce eggs and hormones
• Endometrium


  Lining of the uterus that thickens and renews itself, preparing for pregnancy
• Menstruation


  Woman's monthly bleeding, often called your "period"
• Puberty


  Time in life when a boy or girl becomes sexually mature
• Follicle


  A fluid-filled sac that are found inside a woman's ovaries which contains an immature egg
• Feedback mechanism


  A physiological loop that brings the body either toward or away from the normal, steady state
• Menarche is the first occurrence of period
• Menopause is the time when the ovulation stops
• Menstrual cycle


  1. Pre-ovulatory Period

  2. Follicular Phase

  3. Ovulation

  4. Luteal Phase

  5. Menstrual Phase

  6. Proliferative Phase

  7. Secretory Phase

  8. Post-ovulatory Period
• Hypothalamus and Pituitary Gland are the mastermind of reproduction
• Ovarian follicular phase


  1. Gonadotrophin Releasing-Hormone (Hypothalamus)

  2. Follicle Stimulating Hormone and Luteinizing Hormone (Pituitary Gland)

  3. Theca and Granulosa cells are hormone secreting cells of the ovary

  4. Theca (LH receptors) = Androstenedione

  5. Granulosa (FSH receptors) = Aromatase

  6. Estrogen was secreted to bloodstream

  7. Dominant Follicle increases the secretion of ESTROGEN (POSITIVE FEEDBACK TO PITUITARY GLAND)
• Uterine - Menstrual phase


  Old endometrial lining is shed and eliminated through vagina, producing menstrual period
• Uterine - Proliferative phase


  1. Increase amount of Estrogen

  2. Thickens the endometrium lining
• Ovulation


  1. The release of matured ova from the ovary to the site of fertilization

  2. During Ovulation: sac containing the mature ovum, splits open releasing it from the ovary

  3. Day 14: estrogen levels peek
• Luteal phase


  1. The empty sac left in the ovary (Corpus Luteum) still produces both estrogen and progesterone

  2. High level of progesterone (NEGATIVE FEEDBACK TO THE PITUITARY GLAND) signals that ovulation has occurred

  3. Uterine glands provide more mucus
• Uterine - Secretory phase

  1. After Day 15: Fertilization window starts to close

  2. Around this time the corpus luteum will slowly stops producing estrogen and progesterone as it turns to corpus albicans

  3. Blood vessels in the uterine wall contract and spasm due to the lack of estrogen and progesterone

  4. The uterine lining is shed as menstrual blood beginning the first day of the new cycle
• Reasons for missing a period

  • You are pregnant
  • Your body is still maturing
  • You are under stress at work, home or school
  • You are approaching menopause
  • You've been exercising vigorously
  • You've lost a lot of weight in a short period of time
  • You have a hormone disorder
  • You've been using prescription or street drugs