1. Menstrual Cycle

2. Interaction between the endocrine and reproductive systems. From the Latin “mensis” meaning “month”

3. Defn: Controls (1) the development and release of an egg for fertilization and (2) the preparation of the uterus to receive a fertilized egg.

4. Four stages

5. 1. Follicle phase (~Day 5 - Day 13) Pituitary hormones FSH and LH travel to the ovaries where they cause a follicle to develop. As follicle develops it produces increased amounts of estrogen. This prepares the endometrium.

6. 2. Ovulation (~Day 14) Shortest phase. 3 - 4 days Sudden rush of FSH and LH causes the follicle to rupture and release the ovum.

7. 3. Luteal Phase (~Day 15-28) CL continues to produce estrogen and begins to produce progesterone. Progesterone increases the blood supply to the endometrium and fully prepares it. –If fertilization takes place - zygote divides several times and implants in the endometrium. –CL continues to function for several weeks.

8. 4. Menstruation (~Day 1 - 4) If no fertilizatoion… –egg does not implant –CL begins to disintegrate –levels of progesterone an estrogen fall lining of uterus detaches along with blood and unfertilized ovum is discharged.

9. Menstrual Hormones