|
 |
|
|
 As a result of the changes brought about by puberty, every young woman eventually starts having menstrual cycles. (For more information on MENSTRUAL CYCLES click here.) The average length of a menstrual cycle for a mature woman is 28 days. However, young women, especially teenagers, may have very "irregular" cycles. Some may last two or three weeks, while others may last several months. Most of the time there is no reason for a teenage girl to be concerned if her cycles are not regular. Usually the older she gets, the more consistent her menstrual cycles will become. However, if she is worried about her cycles or experiences lower abdominal pain on a regular basis, she should see her doctor.
During each menstrual cycle, a female experiences what is called menstruation or a "period". "Periods" usually last from three to seven days, and mark the beginning of a particular cycle. The purpose of a "period" is to get rid of the bloody tissue that has accumulated inside her uterus during the course of her menstrual cycle. The thick bloody substance that lines the inside of the uterus is called the endometrium. If the woman happens to be pregnant, she will not have a "period" because the substance that is normally released during her "period" stays inside the uterus to help keep the developing fetus (unborn child) alive. If the woman does not get pregnant, there is no need for this substance to remain in her uterus. Therefore, it begins to break loose and come out of her vagina. Once again, when this occurs, menstruation is taking place - a woman is said to be "on her period".
Another important part of the entire menstrual cycle is something called ovulation. Ovulation is the process by which a mature egg or ovum is released from one of the ovaries. Each female has two ovaries, one on each side of her uterus. Normally, one egg is released at a time from one of her ovaries during each menstrual cycle. Then during the next cycle, an egg will be released from the ovary located on the opposite side of her uterus. Generally, ovulation occurs somewhere in the middle of a woman's cycle. However, because a woman cannot tell when she is about to ovulate, she cannot know for certain when it will take place. That is why there is no 100% safe time to engage in sex and be sure a pregnancy will not occur. A commonly asked question concerning "periods" and pregnancy is, "Can a woman get pregnant when she is on her period?" While it is very unlikely, no one can say it is impossible. The only 100% guarantee a woman has that she will not get pregnant is to not have sex!
After ovulation occurs, the egg is "picked up" by one of the fallopian tubes. There is a fallopian tube on each side of the uterus. It is open near each ovary so that it can receive a mature egg soon after it is released from an ovary. The other end of the tube is connected to the uterus. As a newly released egg cell travels down the fallopian tube, it might join (unite) with a sperm cell which has been released from a male body during sexual intercourse (the physical joining together of a male and female body). The union of a sperm cell with an egg cell is called fertilization. Another word for the fertilization of an egg is conception. Fertilization marks the beginning of a pregnancy, and if all goes well, the fertilized egg (which is called an embryo until the eighth week and a fetus from that time on until it is born) will eventually make its way down the fallopian tube to the uterus and implant in the lining of the uterus (endometrium) where it will develop for the remainder of the pregnancy.
What controls all of these events in the female reproductive system? There are two hormones (special chemical substances) which regulate these activities. They are called estrogen and progesterone. Estrogen is primarily responsible for the changes brought about by puberty, while progesterone has more to do with pregnancy and the development of an unborn child. Both of these hormones cause the lining of the uterus, the endometrium, to thicken during the menstrual cycle. If pregnancy occurs, the production of progesterone continues at a high level to help sustain the health of the baby. However, if there is no pregnancy (an egg is not fertilized by a sperm cell), then the levels of both progesterone and estrogen drop dramatically, and the lining of the uterus sloughs off and is released from the female body, and, once again, the woman has another "period
|
|
|
|
 |
|
|
|
|
|
