October 15, 2010

Birds and Bees Part III

Let me tell you ‘bout the stars in the sky
And a girl and a guy
And the way they could kiss
On a night like this     (Herb Newman)

The egg’s voyage is no less miraculous than sperms’ journey. Ovulation is a volcano-like eruption on ovarian surface of the follicle where the egg was matured. Some women experience this normal monthly event as mid-cycle pain on one side or the other depending on which ovary ovulation occurred. A small strand of muscle fibers called the fimbriaovarica connects the ovary to the fallopian tubes or oviducts. Depending on which side ovulation has occurred this strand of muscle contracts drawing the oviduct closer to the ovary in which ovulation is occurring. The ovulated egg is caught by the sweeping tentacles of the flowered end of the fallopian tube called the fimbria. The fallopian tube’s capture of the egg is facilitated by its enclosure in a surrounding sticky shell-like structure called the zona pellucida, which is further surrounded by a cluster of cells called the corona composed of cumulus cells which nurture the egg and together form the cumulous oophorus whose stickiness allows for an easy catch by the fimbria. The egg is then quite literally swallowed by the fallopian tube and propelled in a conveyor-like fashion by the beating hair-like projections called cilia lining the fallopian tube. Finally the egg reaches the mid-portion of the fallopian tube called the ampullary region where it rests and will die within 24 hours unless successfully courted by an amorous suitor (fertilized).

Joseph A. Hill, III, M.D.

Joseph A. Hill, III, M.D. Board-Certified in Reproductive Endocrinology and Infertility