BIOL 2160 Test 2 notes

BIOL 2160 Test 2 notes - E xam 2 Notes Cancer - 2nd leading...

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Exam 2 Notes Cancer - 2 nd leading cause of death in U.S. (kills > 500,000 people/year) - Causes ~20% of deaths in U.S. each year. - Due to failure of cellular mechanisms that normally control cell division. - This is a result of genetic damage that is often due to tumor-promoting chemicals, hormones, and sometimes viruses. Carcinogens - Environmental substances that induce cancer-causing mutations in cells. - Includes: o UV radiation (excessive sunlight) o Tobacco o Asbestos o Alcohol o Benzene o Lead o Nickel o Countless other chemicals… Oncogenesis - The cancer-forming process. - Result of an interplay between genetics and the environment. - Most cancers are a result of genes being mutated by carcinogens, or by errors in the copying and repairing of DNA. (Inducing cell division makes you at risk for cancer—ex. sunburn making new layer of skin after being peeled off) Tumor - A rapidly proliferating cell type that escapes normal growth restraints and stimulates the growth of vasculature (blood vessels) to obtain oxygen. - Cells that proliferate quickly, and are in abundant supply, are the most dangerous.
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o i.e. skin cells, ovarian cells Metastasis - A case in which cells from the primary tumor (first tumor introduced in body) migrate to new sites where they can form secondary tumors. - Complex process, and invasion of new tissues is non-random, depending on the nature of both the metastasizing cell and the invaded tissue. - Most cancer deaths are due to invasive, fast-growing metastasized tumors. Proliferating Cells - In order for most mutations in oncogenes to cause cancer, they must occur in dividing cells, so that the mutation is passed on. - Mutations in non-dividing cells (most neurons and muscle cells) usually aren’t cancerous. - Brain and muscle cancer are rare conditions in adults (because these don’t divide and don’t get passed on) Location - Cancer frequently originates at sites of injury or infection. - Immune cells migrate to sites of tissue damage, and release growth factors to promote healing. - The extracellular matrix is reconstructed. - These properties may contribute to the establishment and growth of a tumor. Angiogenesis - Recruitment of new blood vessels is required for the growth of all tumors. - Without blood, the average tumor mass can grow to be only ~2 mm in diameter. - Because as new cells are dividing on the outside of the tumor mass, older tumor cells are dying within the tumor mass due to lack of nutrients.
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Viruses that cause cancer - HPV-Human papilloma virus – causes warts on the skin, mouth, genitals, and larynx. Spread through physical contact with infected areas. - ¾ sexually-active people have HPV . Clears up naturally in 1 or 2 years in 90% of cases. - 80% of women will get HPV in their lifetime.
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This note was uploaded on 06/01/2011 for the course BIOL 2160 taught by Professor Kt during the Summer '08 term at LSU.

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BIOL 2160 Test 2 notes - E xam 2 Notes Cancer - 2nd leading...

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