Menstrual Cycle

• Events leading to ovulation/ follicular phase

  1. FSH is released from the pituitary

  2. FSH stimulates the development of the follicle in the ovary /the production of oestrogen by the follicle in the follicular phase

  3. Oestrogen stimulates the proliferation on the endometrium preparing it for implantation/affects the consistency of the cervical mucus making it more easily penetrated by sperm
• Events leading to ovulation/ follicular phase

  4. Peak levels of oestrogen stimulate a surge in the secretion of Luteinising Hormone (LH) from the pituitary gland

  5. This surge in LH triggers ovulation from the ovary.

  6. Ovulation is the release of an egg (ovum) from the follicle in the ovary.

  7. It usually occurs around the mid-point of the menstrual cycle.
• Events following ovulation/ luteal phase

  1. The follicle develops into a corpus luteum

  2. The corpus luteum secretes progesterone

  3. Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation in fertilisation occurs.

  4. Ovarian hormones inhibit secretion of FSH and LH from pituitary

  5. Lack of LH leads to degeneration of corpus luteum and therefore a drop in progesterone levels leading to menstruation

  6. If fertilisation occurs progesterone levels remain high.