The Female Reproductive System

Human reproduction, always an object of the most intense interest, has lately become the darling of the media, the subject of innumerable television talk shows, magazine articles, and newspaper editorials. With each new medical breakthrough in fertility and family planning, the noise level grows higher. From elementary school onward we're now deluged with information, some factual, some not on menstruation and menopause, conception and contraception. Sorting it all out may seem impossible. But a reasonable understanding of the basics of reproduction can make the job easy. As you weigh your options, whether to encourage pregnancy or forestall it, your best resource is a working knowledge of the organs, glands, and hormones that prepare your body for motherhood.
The reproductive system begins at the external genital area or vulva, which runs from the pubic area downward to the rectum. Two folds of fatty, fleshy tissue surround the entrance to the vagina and the urinary opening: the labia majora, or outer folds, and the labia minora, or inner folds, located under the labia majora (Thibodeau and Patton, 2008.) The clitoris, is a relatively short organ (less than one inch long), shielded by a hood of flesh (Reproductive System, 2009.) When stimulated sexually, the clitoris can become erect like a man's penis. The hymen, a thin membrane protecting the entrance of the vagina, stretches when you insert a tampon or have intercourse. From this point onward, the reproductive system leads deeper and deeper into the body.
The vagina is a muscular, ridged sheath connecting the external genitals to the uterus, where the embryo grows into a fetus during pregnancy (Reproductive System, 2009.) In the reproductive process, the vagina functions as a two-way street, accepting the penis and sperm during intercourse, and roughly nine months later, and then serving as the avenue of birth through which the new baby enters the world (Thibodeau and Patton, 2008.)
The vagina ends at the cervix, the lower portion or neck of the uterus (Thibodeau and Patton, 2008.) Like the vagina, the cervix has dual reproductive functions. After intercourse, sperm ejaculated in the vagina pass through the cervix, and then proceed through the uterus to the fallopian tubes where, if a sperm encounters an ovum (egg), conception occurs (Reproductive System, 2009.) The cervix is lined with mucus, the quality and quantity of which is governed by monthly fluctuations in the levels of the two principle sex hormones, estrogen and progesterone. When estrogen levels are low, the mucus tends to be thick and sparse, which makes it difficult for sperm to reach the fallopian tubes. But when an egg is ready for fertilization and estrogen levels are high the mucus then becomes thin and slippery, offering a much friendlier environment to sperm as they struggle towards their goal. This phenomenon is employed by birth control pills, shots and implants. One of the ways they prevent conception is to render the cervical mucus thick, sparse, and hostile to sperm (Reproductive System, 2009.) Later, at the end of pregnancy, the cervix acts as the passage through which the baby exits the uterus into the vagina. The cervical canal expands to roughly 50 times its normal width in order to accommodate the passage of the baby during birth.
The uterus is the muscular organ which holds the developing baby during the nine months after conception (Thibodeau and Patton, 2008.) Like the cervical canal, the uterus expands considerably during the reproductive process. In fact, the organ grows to from 10 to 20 times its normal size during pregnancy (Reproductive System, 2009.) Each month the uterus goes through a cyclical change, first building up its endometrium or inner lining to receive a fertilized egg, then, if conception does not occur, shedding the unused tissue through the vagina in the monthly process called menstruation (Reproductive System, 2009.)
Beyond the uterus, the fallopian tubes connect the rest of the system to the ultimate source of the eggs, the two ovaries (Fallopian Tube, 2009.) Each of these tubes is roughly five inches long and ranges in width from about one inch at the end next to the ovary, to the diameter of a strand of thin spaghetti. The trumpet-shaped part near the ovary has about 20 to 25 feathery projections called fimbria, one of which is attached to the ovary (Fallopian Tube, 2009.) It is the fimbria that each month urges an egg to exit the ovary and begin its trip towards the uterus.
The ovaries are a woman's storehouse of egg cells. They are among the first organs to be formed as a female baby develops in the uterus. At the 20-week mark, the structures that will become the ovaries house roughly 6 to 7 million potential egg cells. From that point on, the number begins to decrease rapidly. A newborn infant has between 1 million to 2 million egg cells. By puberty the number has plummeted to 300,000. For every egg that matures and undergoes ovulation, roughly a thousand will fail, so that by menopause, only a few thousand remain. During the course of an average reproductive lifespan, roughly 300 mature eggs are produced for potential conception (Reproductive System, 2009.) The egg cells remain inactive until puberty, when the reproductive system is activated by a cascade of substances called sex hormones. Then, each month about 20 egg cells, each encased in a sac called a follicle, begin to ripen. Responding selectively to the sex hormones, one follicle becomes dominant while the others shrink away. The egg within the dominant follicle continues ripening to maturity. Then, helped by the feathery fimbria, it exits the ovary and enters the adjacent fallopian tube to be either fertilized or, if conception fails to occur, expelled from the body during menstruation (Reproductive System, 2009.) If fertilization is to occur, it usually happens when the egg's journey is about one-third complete. Once a sperm unites with the egg, its surrounding gelatinous coat releases substances that prevent more sperm from entering.
The fertilized egg then continues on its journey through the fallopian tube (Fallopian Tube, 2009.) About four or five days after fertilization, it enters the uterus and implants itself on the endometrium, which has been primed by the sex hormones to accept and nurture it.
Meanwhile, the follicle that held the egg still has a critical role to play. First it shrinks markedly, and then begins to accumulate fatty substances, or lipids, that give it a yellowish tinge. The resulting structure, now called the corpus luteum (yellow body), produces progesterone and estradiol, two of the hormones critical to reproduction. In a non-pregnant woman, the corpus luteum lasts for about 14 days, after which it shrinks and dries up, eventually becoming a speck of fibrous scar tissue. If conception occurs, however, a hormone from the developing placenta, which surrounds the baby in the uterus, stimulates the corpus luteum to maintain its production of progesterone during the first trimester of pregnancy (Reproductive System, 2009.)
The Reproductive System is unique in that it does little to contribute to the homeostasis of the organism (Reproductive System, 2009.) Rather than being tied to the maintenance of the organism, the reproductive system relates to the maintenance of the species. Having said that, the sex hormones do have an effect on other body systems, and an imbalance can lead to various disorders. For example a woman who has her ovaries removed early in life is at a much higher risk of osteoporosis.
The female reproductive system is designed to carry out several functions. It produces the female egg cells necessary for reproduction, called the ova or oocytes (Reproductive System, 2009.) The system is designed to transport the ova to the site of fertilization. Conception, the fertilization of an egg by a sperm, normally occurs in the fallopian tubes (Fallopian Tube, 2009.) After conception, the uterus offers a safe and favorable environment for a baby to develop before it is time for it to make its way into the outside world. If fertilization does not take place, the system is designed to menstruate (the monthly shedding of the uterine lining). In addition, the female reproductive system produces female sex hormones that maintain the reproductive cycle (Reproductive System, 2009.) During menopause the female reproductive system gradually stops making the female hormones necessary for the reproductive cycle to work. When the body no longer produces these hormones a woman is considered to be menopausal.
The reproductive system interacts with the endocrine system to drive maturation and maintain sexual functions. For examples in males, testosterone contributes to sex drive and function, while estrogen contributes to a female’s ability to bear children. The circulatory system maintains the tissues and provides physical mechanisms for arousal (Reproductive System, 2009.) Penile and clitoral erectile tissue relies on the circulatory system. The endocrine system supplies hormones that allow the female to conceive, give birth, nourish the young, and form an emotional bond with both their mate and their offspring. The central nervous system sends stimuli to the reproductive system to stimulate various processes, including the contractions that occur prior to giving birth (Involvement in the Interactions Between Immune & Reproductive Systems, 2009) The skeletal system sends nutrients such as calcium and magnesium to the fetus, and the circulatory system sends oxygen and nutrients to the fetus, as well as removing toxins from the fetus while it is in the uterus.
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The research that I have analyzed and read is a clear fact that scientist have researched just about everything there is to know about the female reproductive system. The female reproductive system is where life is produced and where females begin the process of menstruation. In between those two there are several other functions of the female reproductive systems. There has been recent research on certain diseases of the female reproductive system such as one disease known as HPV (Human Papilloma Virus). HPV stands for human papilloma virus. There are more than 100 types of HPV (Hyunjung and Haibin, 2010.) Some types produce warts, plantar warts on the feet and common hand warts. About 40 types of HPV can infect the genital area the vulva, vagina, cervix, rectum, anus, penis, or scrotum. Genital HPV infections are very common (Hyunjung and Haibin, 2010.). HPV is so common that about half of all men and more than 3 out of 4 women have HPV at some point in their lives. But most people who have HPV don't know it. Most HPV infections have no harmful effect at all. Some types of HPV may cause genital warts (Hyunjung and Haibin, 2010.) These are called low-risk types of HPV. Some types of HPV may cause cell changes that sometimes lead to cervical cancer and certain other genital and throat cancers (Hyunjung and Haibin, 2010.) These are called high-risk types. This page discusses these high-risk types. Although most HPV infections go away within 8 to 13 months, some will not. HPV infections that do not go away can "hide" in the body for years and not be detected. It is impossible to know exactly when someone was infected, how long they've been infected, or who passed the infection to them. It can lead to cervical cancer as well. There are treatments and methods of prevention available everywhere.
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Reference Page
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Hyunjung Jade, L., & Haibin, W. (2010). Uterine disorders and pregnancy complications: insights from mouse models. Journal of Clinical Investigation, 120(4), 1004-1015. doi:10.1172/JCI41210. (Hyunjung and Haibin, 2010.)
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(2009). Fallopian tube. Columbia Electronic Encyclopedia, 6th Edition, 1. Retrieved from MasterFILE Premier database. (Fallopian Tube, 2009.)
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(2009). Gynecology. Columbia Electronic Encyclopedia, 6th Edition, 1. Retrieved from Academic Search Premier database. (Gynecology, 2009.)
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(2009). Involvement in the Interactions Between Immune & Reproductive Systems. Fertility Weekly, 2-3. Retrieved from Health Source: Nursing/Academic Edition database. (Involvement in the Interactions Between Immune & Reproductive Systems, 2009)
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(2009). Ovary. Columbia Electronic Encyclopedia, 6th Edition, 1. Retrieved from MasterFILE Premier database. (Ovary, 2009.)
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(2009). Reproductive system. Columbia Electronic Encyclopedia, 6th Edition, 1. Retrieved from Academic Search Premier database. (Reproductive System, 2009.)
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Thibodeau, G. A., PhD., & Patton, K. T., PhD. (2008). The Reproductive System. In Structure & Functions of the Body. Structure & Function of the Body (13th Edition ed., pp. 490-515). United States: Tom Wilhelm. (Original work published 1960) (Thibodeau and Patton, 2008.)