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The Menstrual and Ovarian Cycles. The Truth behind PMS!!. What is going on all at once?. The Beginning and the End: Menstruation. Occurs if egg is not fertilized Days 1- 5 Corpus luteum (yellow body) breaks down This causes drop in estrogen and progesterone Uterine lining sheds
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The Menstrual and Ovarian Cycles The Truth behind PMS!!
The Beginning and the End: Menstruation • Occurs if egg is not fertilized • Days 1- 5 • Corpus luteum (yellow body) breaks down • This causes drop in estrogen and progesterone • Uterine lining sheds • FSH increases during
Phase 2: Follicular Phase • Days 5 –13 • Low estrogen = FSH to be released • This stimulates growth of follicle • Egg begins to mature • Follicle matures causing estrogen levels up • Uterine lining begins to thicken again
Phase 3: Ovulation • Days 13-15 • Sudden rush of FSH • Major SPIKE of LH • This causes follicle to break and release egg into fallopian tube • FERTILIZATION MOST LIKELY TO OCCUR AT END OF OVULATION!
Phase 4: Luteal Phase • Days 15-28 • LH and FSH levels crash • Corpus luteum forms from broken follicle • Corpus luteum secretes estrogen and progesterone • This thickens uterine lining to prepare for egg