Fertilization
For fertilization to occur, healthy sperm must be placed in a woman's vagina, near the cervix, around
the time of ovulation .Each sperm is about 1/1000 of an inch long; its whiplike tail moves it up through
the cervix, into the uterus, and into the fallopian tubes. Only one sperm can fertilize an egg, but that
one sperm must be strong enough to swim the equivalent of the English Channel at least three times
without stopping. Though millions of sperm may start the race, only a few hundred survive the trip.
An egg recently released in ovulation is usually picked up by a nearby fallopian tube. Most women
have two fallopian tubes, each about 4 inches long. They are positioned just above the ovaries and
come equipped with featherlike fingers called fimbria (that's Latin for fringes) at the ends nearest the
ovaries. The fimbria and the inside of the tubes are lined with cilia, millions of tiny hairs. These hairs
move the egg from the ovary into the tubes. An egg can be fertilized for only about 12-72 hours after
its release.
Mucus, fluids, and cilia move the egg down into the tube. The fallopian tubes have muscular ligaments
throughout their lengths. In the middle, they actually contract to help the sperm and egg move closer
together and toward conception. At the end nearer the uterus, they tighten to close off and keep eggs
from being released into the uterus too soon.
When sperm are present, they cluster around the egg. They release enzymes from their heads to help
make a hole in the egg to allow penetration.
Once one sperm enters the egg, a reaction occurs that prevents other sperm from entering.
Implantation:
Inside the fertilized egg, cells begin to divide. If all goes well, the fertilized egg then journeys from the
fallopian tube to the uterus where it implants itself in the spongy lining of the uterus. There it grows and
develops into an embryo (weeks 2-8), then a fetus for the rest of the pregnancy, and 9 months later, a
baby.
Numerous structural and hormonal factors play a part in fertility. What may look like the simplest of
human activities -- conceiving a baby -- can become a miraculous chain of events, especially to a
couple having problems getting pregnant.
For fertilization to occur, healthy sperm must be placed in a woman's vagina, near the cervix, around
the time of ovulation .Each sperm is about 1/1000 of an inch long; its whiplike tail moves it up through
the cervix, into the uterus, and into the fallopian tubes. Only one sperm can fertilize an egg, but that
one sperm must be strong enough to swim the equivalent of the English Channel at least three times
without stopping. Though millions of sperm may start the race, only a few hundred survive the trip.
An egg recently released in ovulation is usually picked up by a nearby fallopian tube. Most women
have two fallopian tubes, each about 4 inches long. They are positioned just above the ovaries and
come equipped with featherlike fingers called fimbria (that's Latin for fringes) at the ends nearest the
ovaries. The fimbria and the inside of the tubes are lined with cilia, millions of tiny hairs. These hairs
move the egg from the ovary into the tubes. An egg can be fertilized for only about 12-72 hours after
its release.
Mucus, fluids, and cilia move the egg down into the tube. The fallopian tubes have muscular ligaments
throughout their lengths. In the middle, they actually contract to help the sperm and egg move closer
together and toward conception. At the end nearer the uterus, they tighten to close off and keep eggs
from being released into the uterus too soon.
When sperm are present, they cluster around the egg. They release enzymes from their heads to help
make a hole in the egg to allow penetration.
Once one sperm enters the egg, a reaction occurs that prevents other sperm from entering.
Implantation:
Inside the fertilized egg, cells begin to divide. If all goes well, the fertilized egg then journeys from the
fallopian tube to the uterus where it implants itself in the spongy lining of the uterus. There it grows and
develops into an embryo (weeks 2-8), then a fetus for the rest of the pregnancy, and 9 months later, a
baby.
Numerous structural and hormonal factors play a part in fertility. What may look like the simplest of
human activities -- conceiving a baby -- can become a miraculous chain of events, especially to a
couple having problems getting pregnant.
| Men's Health |
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