Menstrual Cycle

• Menstrual cycle:

  • When: 28 day cycle
  • Where: Ovaries and uterus
  • Why: To produce a mature ovum and prepare the uterus for possible implantation.

  
• Ovarian cycle steps (1 - 5):

  1. Pituitary gland
  2. Secretes: FSH
  3. Stimulates Graffian follicle
  4. Follicle produces oestrogen
  5. Causes Endometrium to thicken/repair

  
• The Menstrual cycle starts when:

  • Pituitary gland secretes LH
  • Matures Graafian follicle

  
• The ovarian cycle refer to the changes in the ovaries.
• FSH and LH cause ovulation to occur
• Ovulation is the release of an ovum into the Fallopian tubes.
• Which TWO hormones does the pituitary gland secrete for the menstrual cycle?


  1. FSH
  2. LH
• FSH stimulates the growth of a follicle into the Graafian follicle.
• Oestrogen is secreted from the Graafian follicle.
• Name the hormone that is secreted by the corpus luteum.


  Progesterone
• If progesterone levels drop then what will occur?

  The endometrium will fall away
• High levles of progesterone inhibits FSH and LH.
• If FSH falls too low then oestrogen levels will also drop.
• Uterine cycle steps (1-5)

  1. Oestrogen from follicle repairs and thickens endometrium
  2. ovulation occurs
  3. Progesterone is released from corpus luteum
  4. Progesterone make the endometium thicker and more vascular
  5. Oestrogen and Progesterone inhibit the secretion of FSH and LH
• Uterine cycle steps (6-10)

  6. if pregnancy does not occur, corpus luteum shrinks

  7. Progesterone levels drop

  8. Oestrogen levels also drop

  9. Endometrium falls away

  10. FSH is no longer inhibited and rises