The female reproductive system
The ovary is the one of the central organs of the female reproductive system. Every woman has two of each on different sides of her uterus, and a protective capsule with numerous follicles encloses them. The follicles cover an egg cell or ovum. Most women have approximately 400,000 ova, which the body releases once a month for the rest of their lives from puberty. An ovum can be fertilized if a sperm penetrates it. At that point, it will attach itself onto the uterine wall and grow into an embryo.
The ovaries also generate progesterone and estrogen, which are primary hormones responsible for control of the menstrual cycle. They also account for sexual development and pregnancy.
In the adult body, an ovary is about 1.6 inches long and 0.8 inches wide. The organ is also 0.6 inches thick and has uneven tissue on its surface. A number of ligaments or fibrous connective tissues support the ovaries. They include the ovarian, broad and suspensory ligaments. An ovary has an outer part called the cortex that contains oocytes, follicles and interstitial cells. It also has an inner component known as the medulla which also has interstitial cells alongside blood vessels, nerves, lymph ducts and fibrous tissue (McLaughlin et. al. 142).
As stated above, the ovary plays a critical role in reproduction. It controls follicular development throughout a woman’s reproductive life. At birth, an ovary will have anywhere between 150,000 to half a million follicles. By the time a woman reaches puberty, the follicles will reduce to 34,000. As the woman gets old, her follicles keep reducing until they degenerate in menopause.
Only about 400 follicles will mature in a woman’s reproductive cycle. Every menstrual cycle starts with the follicular phase. The zona granulosa is the exterior layer of cells enclosing the follicles. It appears right at the beginning of this phase. Another layer of cells called the theca will form when the interstitial cells, as well as the stromal cells, cover this follicle. A mature follicle will then rapture after it has reached 1.2 inches in diameter.
Follicular development lasts for two weeks, and it leads to the production of hormones. One of these is the androgen hormones, which come from the theca. The granulosa then converts androgens to estrogen. A cavity encapsulating the oocyte has progesterone and androgens as well as estrogen. In the last few days of this phase, a mature follicle will rapture thus releasing an egg. The egg descends into the fallopian tube where it moves to the uterus.
The residual cells of the follicle will enter the follicle’s opening. At this point, a corpus luteum will form, and it will contain high concentrations of progesterone for a period of two weeks. When no fertilization occurs, the luteum will reduce in size and progesterone will also diminish. Menstruation occurs to remove the unfertilized egg by shedding the uterine lining. Conversely, if fertilization occurs, then the corpus luteum will not disappear.
It will be in the ovary for the duration of pregnancy, where high concentrations of progesterone will be present. Progesterone is essential in keeping the fertilized egg in place within the uterus so that it can become an embryo. All the above processes depend on the pituitary gland as well as the hypothalamus.
The pituitary and hypothalamus role in ovarian function
The hypothalamus and pituitary glands are all located in the brain. The pituitary gland is at the base of the brain below the hypothalamus while the hypothalamus is below the thalamus. Blood vessels connect the two parts such that hormones from the hypothalamus can control the pituitary gland.
The Luteinizing (LH) and Follicle Stimulating Hormones (FSH) are responsible for the control of ovarian functions. LH stimulates the theca of the ovary to secrete androgen hormones, which granulosa cells convert into estrogen. Ovulation can only occur when a surge of LH occurs within the ovary. This hormone maintains the corpus luteum such that progesterone can be secreted. The FSH performs a different function. It stimulates the follicles so that they can mature.
The hypothalamus plays a critical role in controlling these hormones through secretion of the gonatropin-releasing hormone (GnRH). The neurons of the hypothalamus synthesize GnRH and then bind it onto receptors in the pituitary gland. The work of the GnRH is to cause the secretion of LH which then stimulates the production of estrogen and progesterone. The anterior component of the pituitary gland accounts for the production of FSH and LH.
For the pituitary gland to carry out its functions, it must receive hormones from the hypothalamus. Therefore, these two structures complement one another in regulating the ovarian function. The same cells of the pituitary gland that secrete FSH are also responsible for producing LH.
Cancer cells and their formation
Cancer is a condition of uncontrolled cell growth. The initial cells affected by the cancer will determine the name of the cancer. Healthy cells follow a stage of development, division and finally death. Cancerous cells do not undergo the final phase as they continue to divide and grow leading to incidences of wild cell growth. Typically, this uncontrolled behavior comes from cell damage or DNA mutations. Therefore, the genes responsible for cell development will not work properly.
For instance, the genes responsible for cell termination may fail. Alternatively those ones that restore damaged DNA, cause cell division or tumor suppression may also mutate. These mutations lead to unmanageable growth. Examples of oncogenes include multiple endocrine neoplasia type 2 (MEN2) and Breakpoint cluster region –Abelson (BCR – ABL). Tumor suppressor genes include Tumor Protein 53 (TP53) and Breast Cancer Gene 1 (BRCA1).
The above gene mutations may come about as a result of a category of substances called carcinogens. These are substances that damage the cell and may lead to cancer. Examples include ultraviolet radiation from the sun, X-rays or gamma rays, radiation, tobacco and asbestos. Car exhaust and other pollutants may also cause gene mutations.
The carcinogens work by taking electrons away from biological molecules in the body. The foreign particles exist in the form of free radicals and can damage cells substantially. Alternatively, gene mutations that lead to cancer may originate from hereditary factors. Patients could be born with the mutation or a gene defect that predisposes them to cancer.
Cancer may also come from certain health conditions. If a patient has the human papillomavirus, the individual is likely to develop cervical cancer. HIV, Hepatitis C and B, as well as Epstein-Barr virus, are all dangerous pathogens that can lead to the development of cancer cells. Sometimes gene mutations have no known cause as they can occur simultaneously. If the level of entropy in the cell increases, a mutation can arise.
Studies indicate that cancer cells are present in high numbers within any normal organism. About 10,000 cells may be found in a healthy person. However, these cells do not always manifest as cancer because of a number of reasons. Many of them do not multiply, so they die and leave the body unaffected. The body has an immune system designed to correct unwanted structures. Cancer cells that have the ability to multiply will leave the body because of the immune system.
Sometimes, the number of cancer cells in the body may overwhelm the immune system, so it may not eliminate all of them. Once the latter conditions are present, then cancer will develop from the cancer cells. If DNA mutations occur at a high rate owing to exposure to unfavorable environmental conditions, the disease will manifest. A patient’s diet, their age and their genetic predisposition all amalgamate to create a high rate of gene mutations.
Diagnosis of ovarian cancer
One of the simplest methods of diagnosing ovarian cancer is the pelvic exam. A doctor examines the external or visible parts of the female genitalia; that is the vulva. Subsequently, the gynecologist then uses his fingers to feel the ovaries for any deformities. This exam also involves a speculum, which is an appliance that exposes the vagina for an examination of cervical and vaginal defects.
Some medical professional may use the CA 125 test. This is a blood test that monitors the level of the protein CA 125 in the body. If the protein concentration is high, then chances are that the patient has ovarian cancer. However, because CA 125 may also come from other conditions, then the test is not a conclusive confirmation of ovarian cancer.
A patient may use the ultrasound for diagnosis of the disease. This test does not just detect the presence of ovarian cancer; it also determines the extent of damage caused by the disease. These high frequency sound waves administered on the external part of the body cause images of the inside of the ovaries to be seen. Thus, a physician can detect the configuration and size of the ovaries as well as surrounding parts so as deduce the level of cancer. Sometimes, the ultrasound probe may be placed inside the vagina in order to see the ovaries and their surroundings clearly.
As a confirmatory test, the gynecologic oncologist may perform surgery to test ovarian tissue. This procedure involves abdominal incisions where the professional uses surgical tools to remove body tissue. Usually, the surgeon will collect abdominal fluid or even remove the ovary for analysis.
Breakthroughs in the diagnosis of ovarian cancer enable early detection of the disease. If a person has one of the many susceptibility genes in their system, then this could indicate their predisposition to the disease. Examples include Breast Cancer Gene 1 (BRCA1), Breast Cancer Gene 2 (BRCA2) and Rec A recombinase (RAD51C). Surgical removal of ovarian tissue and analysis enables identification of this disease (Meindl et. al. 476).
Imaging and surgery results can be used to categorize the extent of the cancer. If ovarian cancer is only in the ovaries, then this is stage I. Stage II refers to cancer that has moved beyond the ovaries but is still within the confines of the reproductive system such as the fallopian tubes, the uterus or pelvis. When the cancer spreads to the abdomen or to areas outside the pelvis, that will be stage III. Finally, the cancer may get into the areas outside the abdomen like the lungs or liver. At this point, it will be stage IV cancer.
Works Cited
McLaughlin, John, Barry Rosen,Joel Moody,Tuya Pal,Isabel Fan,Patricia A. Shaw, Harvey A. Risch,Thomas A. Sellers,Ping Sun and Steven A. Narod. “Long term ovarian cancer survival associated with mutation in BRCA1 and BRCA2.” Journal of the National Cancer Institute 105.2(2013): 141-148. Print.
Meindl, Alfons, Katharina Eirich, Stefanie Engert, Alexandra Becker, Daniela Endt, Nina Ditsch, Rita K. Schmutzler & Detlev Schindler. “Germline RAD51C mutations confer susceptibility to ovarian cancer.” Nature Genetics 44(2012): 476. Print.