Sperm Egg Describe life a sperm life egg start finish. Cover points story: - Trace movements sperm
Where It All Started
In order to properly chronicle the journey of a sperm and egg to fertilization, one must begin with the factors responsible for their creation. It all starts with a thought -- or, from a release from the brain. For sperms to be created, the pituitary gland (which is inside the brain) receives a hormone known as GnRH that causes it to produce the two key chemicals responsible for sperm production (Rosick 2003). The first is called follicle stimulating hormone and the second is known as lutenizing hormone.
Once these hormones are created, sperm development can actually begin in the lower portions of seminiferous tubules, which are located inside of the testicles. The lower part of these tubules are known contain sertoli cells, in which sperm creation begins. Gradually, sperms mature and move up the seminiferous tubules in which they become full grown, with their head and tail, before beginning their long trek towards pregnancy by exiting into the epididymis.
Sperm finish their development in the epididymis. During certain periods of heightened arousal -- which has been known to take place during sexual intercourse, an irrepressible orgasm can cause sperm cells to move into the vas deference, just outside of the prostate gland, into the ejaculatory duct. Aided by the release of fluid from the prostate gland, the sperm continue on into the urethra before exiting out of the penis into the vagina. The real work starts at this phase of the journey. After being ejaculated inside a woman, the sperm attempt to swim through the cervix and into the uterus. The cervix can secrete a form of mucus that is conducive to fertility. The cervix can also release fluids that are not conducive to fertility and which may serve to ward off sperm. Next the sperm has to traverse the entire uterus to get to the fallopian tube, to try to catch a date with destiny -- or with an egg cell that should be coming soon, hopefully.
The hard part, of course, is reaching the fallopian tube. There are numerous reasons for sperm to fail, such as their traveling in errant directions, or simply running out of energy. Once at the fallopian tube, however, sperm has just a matter of days to wait for an egg that has been released and to fertilize it. At this point it is just a waiting game, with the sperm loitering rather conspicuously about the opening of the fallopian tubes, which is near the lower part of it. All it takes is just one sperm, of course, in order to fertilize and egg, in order to produce a child.
Egg cells are engendered by a fairly lengthy process that is aided by a number of factors. One is that all women are born with every egg that they will ever have -- barring some surgical procedure -- at the time of their birth. There are approximately 400,000eggs that women are born with although they do not begin to mature and be released through the body until puberty and menstruation around the time girls turn about 12 years of age. Similar to the process for the creation of sperm, the process for the releasing of an egg in a women begins with the secretion of hormones by the pituitary gland inside the brain. These hormones, again, are follicle stimulating hormones. The latent eggs that a woman is born with are inside of her ovaries. Once the When FSH is released, follicles begin to grow inside the ovary and consist of the fledgling egg and other cells that aid in its development.
There is a little bit of a race between the competing follicles for growth, because the one that can mature quickest and assert itself the most is able to secret another hormone known as estrogen. Estrogen goes into the uterus and helps line it is a matter that is conducive to fertilizing the egg (No author 2011). Simultaneously, estrogen within particles of blood secretes lutenizing hormones which really give a boost in development to the maturing egg. Once the lutenizing hormones kick in, the follicle is able to eventually burst and disseminate the egg cell by means of ovulation. Following the release of the egg, the follicle continues to help it on its journey by releasing yet another hormone, progesterone, which also goes to the lining of the uterus to prepare it to be more conducive to the fertilization of the egg. Once the egg leaves the ruptured follicle, of course, it is fated to be received into that uterus lining. It gets a significant helping hand -- or in this case, helping tentacles, so to speak -- by fimabriae, which are tiny structures that push the egg into the fallopian tube as it tunnels towards the uterus.
The poor egg has no longer than a day's time to meet with a sperm cell at the base of the fallopian tube before it will cease development and eventually die, being shed through the menstrual cycle. But if there is a sperm waiting for it near the entrance of the fallopian tube, it will become fertilized by the happy candidate and they will never part company again.
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