BIOL 2160 Test 2

BIOL 2160 Test 2 - B IOL 2160 Human Physiology C ANCER 2nd...

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BIOL 2160 – Human Physiology CANCER 2 nd leading cause of death in the US (kills > 500,000 people per year) Causes ~20% of deaths in US 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 Carcinogens environment substances that induce cancer-causing mutations in cells Includes: o UV radiation (excessive sunlight) o Tobacco o Asbestos (illegal now) o Alcohol o Benzene o Lead o Nickel o Countless other chemicals… They can damage your DNA and cause mutations they switch up the order in DNA switching Gs with Ts. . etc. cells keep dividing and copying the mutated DNA hard to stop Oncogenesis
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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 (though mostly accurate – it can make mistakes) Tumor 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 o Example: skin cells, ovarian cells, bone cells Metastasis Metastasis a case in which cells from the primary tumor 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 passing on. Mutations in non-dividing cells (most neurons and muscle cells) USUALLY aren’t cancerous. Brain and muscle cancer are rare conditions in adults. Location Cancer frequently originates at sites of an injury or infection.
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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 Whether or not a tumor becomes bigger and dangerous, depends on 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 ~2mm 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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BIOL 2160 Test 2 - B IOL 2160 Human Physiology C ANCER 2nd...

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