The follicle that ruptured to expel the egg remains on the ovary.  Almost immediately, the hormone LH (leutinizing hormone) begins to change the burst follicle into a yellow-colored piece of tissue called the "corpus luteum" (literally meaning "yellow body").  The corpus luteum begins to secrete progesterone with a small amount of estrogen.  Progesterone will decrease the amount of LH in the blood.   The corpus luteum will continue to secrete progesterone for at least the next two weeks, when you will either get your period or become pregnant. 

 

Cervical fluid   Within an hour to a day later, the egg-white cervical fluid you noticed during ovulation will dry up.  Your cervical fluid might feel sticky or even nonexistent at this time.  Usually this will progress to lotiony cervical fluid within about a week's time. 

 

Ovulation spotting  You may notice spotting the day of or the day after ovulation occurs.   This happens when a bit of blood, released from the burst follicle, makes its way through your tubes, your uterus, and out of your cervix.  Not everyone notices or has this symptom. 

 

Breast tenderness  After ovulation occurs, the hormonal changes in your body can make your breasts tender and sore.  You might also get sore nipples at this time.  Many often think that breast changes are a sign of pregnancy, but they are normal during any cycle.  However, an increase in tenderness can indicate pregnancy, as can tenderness when you normally don't have any.

 

Increased libido  Your body's natural tendancy when not pregnant is to become pregnant - even when you don't want to be.  You will most likely notice an increased desire for sex in the time leading up to and during ovulation.

 

What are the chances I'll get pregnant?  If you have sex anywhere from 5 days prior to or 1 day after ovulation, you have a chance of getting pregnant!  The highest chance exists the day prior to and the day of ovulation.  Once sex has occured, approximately 100 million to 300 million sperm are injected into your vagina.  Your cervix, located at the end of your vagina, is usually closed tightly, but if you have sex during ovulation, your cervix will be open to allow the easy passage of sperm into your uterus.  The sperm cells use a liquid called semen to get into your uterus, and then they use the fluid within your uterus to move around.  Of that large number, only 3,000,000 sperm cells actually make it through your cervix and into your uterus!  Since only one tube holds the egg, many of these sperm will swim up the wrong tube and never find an egg to fertilize.  The ones that do choose the right tube will encounter roadblocks as they search for the egg.  Many get pushed back by the constant motion of the fallopian tubes.  Others get tangled in the cilia of the tubes.  Still others get attacked by white blood cells searching for "intuders."  It is estimated that only 500 sperm actually reach the egg!  This is one way to make sure that only the strongest and healthiest sperm reach the egg.

 

Sperm have been known to live for up to 5 days, which is why you can get pregnant from having sex 5 days before ovulation!  The time that fertility is at its highest is the day before ovulation; that way the sperm are waiting in place before the egg is ovulated.  The egg only lives for 24 hours, so any sex that occurs more than 24 hours after ovulation has occured should not result in pregnancy. 

 

Egg

 

Fimbriae

 

Addominal cavity

 

What is happening in my body?  Last week ended with an egg being expelled out of an ovary and into the abdominal cavity. The egg might have been lost in your abdomen if not for the actions of the fallopian tubes. There are two fallopian tubes, each branching off of the uterus and opening onto an ovary.  The part of the tube closest to the ovary has finger-like projections called fimbriae that move over the surface of the ovary in a constant, wave-like motion.  This motion will sweep the newly ovulated egg up and into the fallopian tube. Once the egg is in the tube, more finger-like projections, called cilia, continue to brush the egg towards the uterus. 

 

Videos

 

From the moment of conception, the baby's entire genetic makeup is determined. The fertilized egg burrows itself into the side of mom's uterus, preparing for the lengthy journey ahead. After just six days, one cell develops into nearly 200 and by the end of the third week the brain begins to form. From Discovery Health.

 

What happens at the moment of conception? Embryologist Ian Gallicano, M.D., describes the delicate cellular choreography that creates a new life. From Discovery Health.

 

Most of the time, when a cell in our bodies divides, each new cell carries a complete set of chromosomes. The cells involved with human reproduction, however, carry only half after division occurs. In this step-by-step explanation, learn about mitosis and meiosis, the two types of cell division.  From Nova Online.

 

Covers advantages of sexual reproduction, sperm formation, and meiosis. Running time 09:53. From Nova Online.

 

Covers a story about expectant parents, egg formation, ovulation, travel through the  fallopian tube, finding a mate, and sexual intercourse. Running time 6 minutes.  From Nova Online.

 

Covers obstacles faced while seraching for the egg, what happens upon reaching the egg, and the process of entering the egg (fertilization). Running time 05:41. From Nova Online.

 

Covers DNA combination, cell division, embryo implantation, and morning sickness. Running time 04:58. From Nova Online.

 

Winamp image of cleavage while traveling through the fallopian tube.  Click "Open" in the window that pops up.

 

What is happening with my baby?

 

Fertilization Once the egg has been swept into the fallopian tube (assuming there are sperm present from sex a few days prior to or

 

the day of ovulation) the egg will be

 

covered with sperm.  The egg is

 

surrounded by a protective layer, called

 

the zona pellucida, which houses little

 

receptors (think of them as wall outlets). 

 

The sperm that cover the egg are

 

searching for a receptor to "plug into."

 

Once the sperm find and begin plugging

 

into receptors on the egg, the front of

 

their heads release a chemical,

 

called acrosome, that breaks down the

 

zona pellucida so that each sperm can

 

drill a hole to get to the egg. 

 

Once the sperm have made it through the zona pellucida, which takes about 20 minutes, they finally encounter the actual egg cell, known as the oocyte.  The sperm cell that does this the fastest is able to bind to the oocyte.  When this happens, the zona pellucida hardens and locks any competing sperm cells in place so that only one sperm is able to fertilize the egg.  The sperm cell that made it into the oocyte releases its DNA into the egg.  Fertilization has just occured!

 

DNA Combine When the sperm cell enters the egg, the new creation they form is called a zygote, and it is the first of many steps your baby will make on the road to birth.  Within 12 hours from fertilization, the DNA from both the sperm and the egg

 

join together and form a unique combination of DNA that your baby will have in every cell of his or her body for the rest of his or her life.  This DNA will determine, based on the genes that were passed on by you and your partner, whether your baby is a boy or a girl, whether he or she has brown eyes or blue, brown hair or blond, is tall or short, and whether he or she likes to read or prefers sports.  Everything your child will be is mapped out in this one instant!  Pretty amazing!

 

Cell Division Now that the two cells have become one, one cell must become two.  The zygote undergoes something called mitosis, also known as "cleavage."  Within a few hours of the DNA fusing together, the DNA will make a clone of itself.  The two copies of DNA will be pulled to opposite ends of the cell, and the cell will split down the center, resulting in two seperate cells with the same DNA in each one. (To view this in action, click on "How Cells Divide" in the video box on the right side of this page, and pay close attention to the left side of the screen.) After the first cell division takes place, a chemical is secreted from the zygote called Early Pregnancy Factor (EPF). Without EPF, your body might mistake the zygote for a foreign body (like a bacterium or virus) and attack it.  With EPF, your baby can continue to develop safely.  Approximately every 20 hours, each cell will split again - leading to 4 cells, then 8 cells, then 16 cells.  When they have split into 16 cells, the zygote becomes a morula, which is Italian for muberry.  Using the fluids within your reproductive system, the morula begins to float toward the end of the fallopian tube, headed for the uterus.  The cells of the morula rely on the nutrients stored in the egg that you produced for nourishment.

 

Cell Differentiation   When the 16- to 32-cell morula enters the uterus, distinct changes start to occur.  In the fallopian tube, the cells of the morula were clumped together in a cluster.  Now, however, the cells cling to the outer ring of the cell membrane, leaving a hollow, fluid-filled space in the center of the morula. When the cells make this transition, the morula becomes known as a blastocyst.  It is at this point that the cells within the blastocyst start to do different jobs - known as differentiation.  Some cells clump together on one side.  These cells will become the baby, while the remaining cells in the outer ring, called the trophoblast, will become the placenta, the amniotic sac, and the umbilical cord.

 

Week 1

 

Of Note This Week

 

Wondering what it is and what it does?  Click here to find out!

 

Human Egg

 

Human Sperm

 

Copyright © 2004 Choice to Live With, Inc.

 

(3 weeks since your last period)