Biology Questions With Citations – Essay Example

Biology questions with citations Question How does a Pap smear detect cervical cancer? Cervix, which is the lower end of the uterus that opens into the vagina, is covered by a tissue lined by a thin layer of cells. In the process of development, the cells may become abnormal due to factors such as infection, use of the oral contraceptive pill, smoking etc. At times, the abnormal cells can begin to multiply out of control and form pre-cancerous lesions that could develop eventually into tumors. Hence, they need to be removed to prevent cervical cancer. Infection with certain genital forms of the common human papilloma virus (HPV) such as HPV Types 16 and 18, can cause cervical pre-cancer and cancer. The Pap smear or Pap test consists of obtaining a collection of sample cells from the cervix which is smeared onto a glass slide and examined under a microscope by the histopathologist for abnormal/ cancerous cervical cells that indicate precancer changes. The Pap smear does not detect other gynecological cancers including ovarian cancer.
How is HPV spread and how common is it?
HPV is highly contagious and can be transmitted by all kinds of sexual activity involving genital contact, not restricted only to sexual intercourse. Genital HPV infection is very common and could be said to be a normal aspect of life of a sexually active woman. HPV infections are usually self-limiting and without any ill-effects.
What are the symptoms of an HPV infection in men and what are the symptoms in women?
Mostly people with HPV may not have any signs or symptoms. And in a majority of cases, the infection usually self-limiting and without any ill-effects gets cleared naturally by the individual’s immune system within two years. With some types of HPV, infected males as well as females can develop genital warts. In rare cases, these types of HPV infection can also lead to a condition known as recurrent respiratory papillomatosis or RRP which is characterized by the presence of warts in the throat.
What serious health problems can the virus cause in men and in women?
The other serious health problems due to HPV infection in women only are cervical cancer, cancers of the vulva and vagina; cancer of the penis in men only; and cancers of the anus, and head and neck including tongue, tonsils and throat in both women and men. Genital warts-causing HPV are different from the HPV types that cause the cancers.
(Sources: http://www.cervicalcancer.com.au/about-cervical-cancer; and
http://www.cdc.gov/STD/HPV/STDFact-HPV.htm)
Question #2
Difficulty in urination in men aged 50 and above usually indicates an underlying prostate disease. The common problems associated with the prostate are Prostatitis usually caused by bacterial infection, prostate enlargement due to Benign prostatic hyperplasia (BPH), and prostate cancer. All the above diseases of the prostate cause an elevated serum PSA level. Also, urethral trauma due to urinary tract infections could raise serum PSA levels.
PSA or Prostate-specific antigen is a tumor marker used for early detection of prostate cancer. PSA is a protein which is concentrated in the prostatic tissue and its level in serum is normally very low. Any damage to the prostatic structure caused by e.g., prostatic disease, inflammation or trauma causes greater amounts of PSA to enter the circulation (Zieve, 2009).
Question #3
Exposure, however brief, to isotretinoin during pregnancy is associated with a high risk of major fetal malformations at all therapeutic doses of isotretinoin. Congenital malformations associated with isotretinoin-exposed pregnancies include serious craniofacial and central nervous system malformations (Bérard et al., 2007). One of the most severe effects of alcohol consumption during pregnancy is fetal alcohol syndrome (FAS). FAS is a group of problems that lasts a lifetime and includes, among others, mental retardation, abnormal facial features and problems of the central nervous system. Two chemicals with overtly similar effects and producing exaggerated effects because of enhanced combination action when used concurrently are said to have synergistic effects.
(Sources: Bérard, et al., 2007; and
Fetal Alcohol Syndrome, MedLine Plus. Accessed 18 April 2010
http://www.nlm.nih.gov/medlineplus/fetalalcoholsyndrome.html)
Question #4
Tubal ligation (or "tying the tubes") is a form of surgical sterilization which closes a womans fallopian tubes that connect the ovaries to the uterus. Performed under general anesthesia, this procedure permanently prevents the transport of the egg to the uterus. After this surgery, my cousin can no longer get pregnant because although her ovaries continue to release eggs, the eggs are stopped in the tubes and reabsorbed by the body. However, her hormone levels and menstrual cycle will remain unaffected by this method of sterilization. Therefore, her fears that tubal ligation will make her “menopausal” are unfounded (Storck, 2009).
Question #5
Marian could be having kidney stones (renal calculi). (Stöppler, M.C., 2008)
References
Bérard, A., Azoulay, L., Koren, G., et al., 2007. Isotretinoin, pregnancies, abortions and
birth defects: a population-based perspective. British Journal of Clinical
Pharmacology, 63(2): 196–205
Stöppler, M.C., 2008. Kidney stones: symptoms, causes, and treatment. Medicine
Net.com. Accessed 18 April 2010
http://www.medicinenet.com/script/main/art.asp?articlekey=46662
Storck, S. 2009. Tubal ligation. Medline Plus. Accessed 18 April 2010
http://www.nlm.nih.gov/medlineplus/ency/article/002913.htm
Zieve, D. 2009. PSA. MedLine Plus. Accessed 18 April 2010
http://www.nlm.nih.gov/medlineplus/ency/article/003346.htm