arcanegirl
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Sperm Invasion
Spermatozoa can be seen invading the cervical mucus within seconds after ejaculation, but most will not make it. Of some 200 million sperm deposited into the vagina near the cervix in a typical ejaculation, only 100,000 ever get into the womb. Thus, over 99.9 percent of the sperm never have a chance of getting beyond the vagina.
Once the sperm enter the canal of the cervix, they are capable of fertilizing the egg for as long as forty-eight to seventy-two hours, though they may actually live for up to six days. Remember, since the egg is only fertilizable for about twelve hours after ovulation, it is important to have a continuing flow of sperm across the tube so that whenever the egg appears, there will be sperm available. In this sense, the canal of the cervix can be looked upon as a receptacle through which platoons of spermatozoa migrate and in which some are detained in order to ensure a continuous supply of smaller numbers, over a prolonged period of time, to the deeper recesses of the female where fertilization takes place. Of course, these delaying mechanisms can do more harm than good in infertile couples if events do not allow the invasion of sperm to be mounted successfully.
To understand how this invasion of sperm gets launched effectively, we must first understand the remarkable liquid that covers the opening of the womb-the cervical mucus. The cervical mucus presents a very effective barrier to bacteria and thus protects the womb against infection. It is a selective filter, which favors normally active sperm and excludes other objects (including poor-quality sperm) from access. But it doesn't even permit access to normal sperm except during a specific period at midcycle when ovulation is imminent and fertilization is possible. Cervical mucus resembles a thick, clear liquid that can be poured from one container into another. However, in a technical sense, it is not a liquid. As it is being poured, it can actually be cut with scissors; therefore, although it seems to behave as a thick liquid, it also has the characteristics of a very pliable, transparent plastic.
Cervical mucus is absent or very scanty during most of the monthly cycle, gradually becoming more abundant around the middle of the cycle, under the influence of increasing estrogen levels,when ovulation is about to occur. Just prior to ovulation it becomes almost optically clear, although it is translucent at other times. At the moment when fertilization is possible, near the time of ovulation, the mucus can be stretched out into a very thin strand; at other times in the cycle it is more sticky, and if stretched it will break. All of these changes in the cervical mucus, which occur around the time prior to ovulation, are designed to help sperm gain access to the uterus. The more liquidlike character, the greater transparency, and the greater stretchability (called Spinnbarkheit) are all characteristics that favor the successful invasion of an army of sperm. When the mucus is sticky and thick, not as abundant, and translucent rather than transparent, it is difficult if not impossible for any sperm to gain access.
Microscopically, the cervical mucus consists of a dense mesh that, during most of the monthly cycle, represents a solid barrier to invasion. Just prior to ovulation, under the effect of the female hormone estrogen, mucus production rises tenfold, and the water content of the mucus increases. The otherwise impenetrable mesh opens up and allows a successful invasion of sperm.When semen first reaches the cervical mucus after ejaculation, a clear barrier line can be seen separating the two different fluids. Semen does not "mix"with cervical mucus. Soon, however, phalanges of sperm begin to penetrate the mucus, forming branching structures that invade it.
Observing the sperm's penetration of the cervical mucus under the microscope is an exciting event. Sperm at first seem to against the cervical mucus without any evidence that they will ever be able to gain access. Their movements while in the ejaculate are haphazard and not specifically aimed toward the mucus. However, within a matter of minutes, one or two spermatozoa begin to make an indentation in the line separating the cervical mucus from the ejaculate. Once one sperm has been able to initiate the penetration of the mucus, other sperm then quickly follow at that same point of entry. Sperm then continue to invade the cervical mucus at that point much like a single-file line of army ants. Only one or two spermatozoa at a time can pass through this entrance.
The sperm swim in a straightforward direction along parallel rows of the invisible microscopic molecular structure of the mucus. Once this invasion of the cervical mucus has been established, sperm can reach the fallopian tubes in about thirty minutes.
Pregnancy would not be likely if all the sperm got into the fallopian tubes at one time, because they would soon pass on into the abdominal cavity, and not be available to fertilize the egg except during a very brief, lucky interval. If they were not lucky enough to pass through the fallopian tube at exactly the moment of ovulation (or within twelve hours of ovulation), they would be long gone by the time the egg arrived. Thus, nature had to invent some mechanism for allowing a continuous entry to the site of fertilization by a smaller number of sperm. To accomplish this, the cervix and the cervical mucus act as a reservoir from which spermatozoa are slowly released into the uterus and up to the fallopian tubes over a period of several days.
Spermatozoa can be seen invading the cervical mucus within seconds after ejaculation, but most will not make it. Of some 200 million sperm deposited into the vagina near the cervix in a typical ejaculation, only 100,000 ever get into the womb. Thus, over 99.9 percent of the sperm never have a chance of getting beyond the vagina.
Once the sperm enter the canal of the cervix, they are capable of fertilizing the egg for as long as forty-eight to seventy-two hours, though they may actually live for up to six days. Remember, since the egg is only fertilizable for about twelve hours after ovulation, it is important to have a continuing flow of sperm across the tube so that whenever the egg appears, there will be sperm available. In this sense, the canal of the cervix can be looked upon as a receptacle through which platoons of spermatozoa migrate and in which some are detained in order to ensure a continuous supply of smaller numbers, over a prolonged period of time, to the deeper recesses of the female where fertilization takes place. Of course, these delaying mechanisms can do more harm than good in infertile couples if events do not allow the invasion of sperm to be mounted successfully.
To understand how this invasion of sperm gets launched effectively, we must first understand the remarkable liquid that covers the opening of the womb-the cervical mucus. The cervical mucus presents a very effective barrier to bacteria and thus protects the womb against infection. It is a selective filter, which favors normally active sperm and excludes other objects (including poor-quality sperm) from access. But it doesn't even permit access to normal sperm except during a specific period at midcycle when ovulation is imminent and fertilization is possible. Cervical mucus resembles a thick, clear liquid that can be poured from one container into another. However, in a technical sense, it is not a liquid. As it is being poured, it can actually be cut with scissors; therefore, although it seems to behave as a thick liquid, it also has the characteristics of a very pliable, transparent plastic.
Cervical mucus is absent or very scanty during most of the monthly cycle, gradually becoming more abundant around the middle of the cycle, under the influence of increasing estrogen levels,when ovulation is about to occur. Just prior to ovulation it becomes almost optically clear, although it is translucent at other times. At the moment when fertilization is possible, near the time of ovulation, the mucus can be stretched out into a very thin strand; at other times in the cycle it is more sticky, and if stretched it will break. All of these changes in the cervical mucus, which occur around the time prior to ovulation, are designed to help sperm gain access to the uterus. The more liquidlike character, the greater transparency, and the greater stretchability (called Spinnbarkheit) are all characteristics that favor the successful invasion of an army of sperm. When the mucus is sticky and thick, not as abundant, and translucent rather than transparent, it is difficult if not impossible for any sperm to gain access.
Microscopically, the cervical mucus consists of a dense mesh that, during most of the monthly cycle, represents a solid barrier to invasion. Just prior to ovulation, under the effect of the female hormone estrogen, mucus production rises tenfold, and the water content of the mucus increases. The otherwise impenetrable mesh opens up and allows a successful invasion of sperm.When semen first reaches the cervical mucus after ejaculation, a clear barrier line can be seen separating the two different fluids. Semen does not "mix"with cervical mucus. Soon, however, phalanges of sperm begin to penetrate the mucus, forming branching structures that invade it.
Observing the sperm's penetration of the cervical mucus under the microscope is an exciting event. Sperm at first seem to against the cervical mucus without any evidence that they will ever be able to gain access. Their movements while in the ejaculate are haphazard and not specifically aimed toward the mucus. However, within a matter of minutes, one or two spermatozoa begin to make an indentation in the line separating the cervical mucus from the ejaculate. Once one sperm has been able to initiate the penetration of the mucus, other sperm then quickly follow at that same point of entry. Sperm then continue to invade the cervical mucus at that point much like a single-file line of army ants. Only one or two spermatozoa at a time can pass through this entrance.
The sperm swim in a straightforward direction along parallel rows of the invisible microscopic molecular structure of the mucus. Once this invasion of the cervical mucus has been established, sperm can reach the fallopian tubes in about thirty minutes.
Pregnancy would not be likely if all the sperm got into the fallopian tubes at one time, because they would soon pass on into the abdominal cavity, and not be available to fertilize the egg except during a very brief, lucky interval. If they were not lucky enough to pass through the fallopian tube at exactly the moment of ovulation (or within twelve hours of ovulation), they would be long gone by the time the egg arrived. Thus, nature had to invent some mechanism for allowing a continuous entry to the site of fertilization by a smaller number of sperm. To accomplish this, the cervix and the cervical mucus act as a reservoir from which spermatozoa are slowly released into the uterus and up to the fallopian tubes over a period of several days.
sone interesting stuff here hun 
