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Flashcards by sabrinapar22, updated more than 1 year ago
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Created by sabrinapar22
almost 10 years ago
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| Question | Answer |
| What are the three major categories of risks that can harm human health? | -physical (environmental factors such as natural disasters, exposure to UV radiation, radioactive substances) -biological (associated with diseases) -chemical (exposure to chemicals) |
| What is a disease? | any impaired function of the body with a characteristic set of symptoms |
| Which category of human health risks causes the most human deaths? | biological -3/4 of human deaths worldwide |
| infectious diseases | caused by infectious agents (pathogens) -eg. pneumonia, STDs |
| Which six types of illnesses account for 94% of all deaths caused by infectious diseases? | -respiratory infections 30% -HIV/AIDS 21% -diarrheal diseases 14% -tuberculosis 12% -malaria 9% -childhood diseases 8% -other 6% |
| chronic diseases | slowly impair the functioning of a person's body -eg. heart disease, cancers |
| acute diseases | rapidly impair the functioning of a person's body -eg. Ebola |
| leading health risks for chronic disease of low income countries, from greatest risk to least | -low weight during childhood -high blood pressure -unsafe sex -unsafe water, sanitation, hygiene -high blood glucose -indoor smoke from solid fuels -tobacco use -physical inactivity -suboptimal breast feeding -high cholesterol |
| leading health risks for chronic disease of high income countries, from greatest risk to least | -tobacco use -high blood pressure -overweight and obesity -physical inactivity -high blood glucose -high cholesterol -low fruit and vegetable intake -urban outdoor air pollution -alcohol use -occupational risks |
| epidemic | a rapid increase in disease caused by a pathogen |
| pandemic | an epidemic that occurs over a large geographic region such as an entire continent |
| plague | -bubonic plague, Black Death -caused by infection from bacterium Yersinia pestis carried by fleas -transmitted to people by flea bites or contact with rodents -swollen glands, black spots on skin, extreme pain -killed 1/4 of European population in 1300s -last major pandemic occurred in 1900s Asia -antibiotics kill bacterium if infected |
| malaria | -caused by infection from protists in genus Plasmodium --parasite spends one stage of life in mosquito and another stage inside a human -flulike symptoms -350 to 500 million/year infected -1 million people die (mostly under age of five) -subsaharan Africa, Asia, Middle East, Central and South America -eradicated in US through use of DDT |
| tuberculosis | -caused by becterium Mycobacterium tuberculosis -highly contagious, spread when parseon coughs and expels bacteria in air -bacteria persists for several hours -infects lungs -weakness, night sweats, coughing blood -1/3 of world population is infected -9 million/year infected, 2 million die -treated by taking antibiotics for 1 year |
| What happens when a patient does not take the prescribed dose of medicine for the full duration time? | -pathogen quickly rebuilds population -the last few bacteria are the most resistant to drugs -20% of infected people in Russia and Africa carry drug resistant strain |
| emergent infectious diseases | infectious diseases that were previously not described or have not been common for at least the prior 20 years -world average of 1 emergent disease / year -pathogens jump unexpectedly from animal hosts to human hosts |
| AIDS | -Acquired Immune Deficiency Syndrome -caused by HIV |
| HIV | -Human Immunodeficiency Virus -spread through sexual contact, shared drug needles -hunters in Cameroon ate infected chimpanzees -33 million infected with HIV -25 million died from AIDS related illnesses -antiviral drugs extend life |
| Ebola Hemorrhagic Fever | -caused by Ebola virus -50 to 89% death rate of infected individuals -fever, vomiting, internal and external bleeding -no drugs -no known source; primates suspected |
| Mad Cow disease | -bovine spongiform encephalopathy BSE -pathogen slowly damages cow's nervous system -prions in brain mutate into deadly proteins that act as pathogens -loss of coordination, death -transmitted to other cows by eating infected nervous system -transmitted to humans by infected meat, can't be destroyed by cooking -humans develop Creutzfeldt Jakob disease |
| bird flu | -Spanish flu, avian influenza -cause by H1N1 virus -fatal to domesticated birds -H5N1 jumps from birds to people -humans have few defenses against H5N1 because we have no evolutionary history with it -destroy birds to stop disease -mutations could allow disease to be spread among people, will kill 150 million |
| West Nile Virus | -transmitted among birds by mosquitoes -1973 West Nile first human case -inflammation of brain leads to illness and death -arrived in NY 1999, highest number of infections in 2002 and 2003 |
| How are diseases combated in low income countries? | -improvement in nutrition, availability of drinking water, proper sanitation |
| How is disease combated in high income countries? | -promote healthier lifestyle choices (physical activity, balanced diet, limit of excess food and tobacco use) |
| How is disease combated in both high and low income countries? | -continued education about the spread of diseases -rapid response plans when new diseases appear |
| neurotoxins | -chemicals that disrupt the nervous system of animals -eg. insecticides interfere with insect's nervous system -lead and mercury cause damage to human's kidneys, brain, and nervous system -lead exposure has declined, mercury remains a problem |
| carcinogens | -chemicals that cause cancer -cell damage, uncontrolled cell growth caused by interference with cell's metabolic processes or by damaging the genetic material of the cell (mutagens) -eg. asbestos, radon, formaldehyde, tobacco chemicals |
| mutagens | carcinogens that cause damage to the genetic material of a cell |
| teratogens | -chemicals that interfere with the normal development of embryos or fetuses -eg. alcohol reduces growth of fetus and damages brain/nervous system |
| allergens | -chemicals that cause allergic reactions -capable of causing an abnormally high response from immune system, causing breathing difficulties and death -eg. chemicals in peanuts milk, drugs |
| endocrine disruptors | -chemicals that interfere with the normal functioning of hormones in an animal's body -endocrine disruptors cause low sperm counts in men and increased risk of breast cancer in women |
| dose-response studies | -expose animals or plants to different amounts of a chemical and then observe a variety of possible responses (mortality, changes in behavior/reproduction), but mainly mortality -sub lethal effects -chemical amounts measured as concentration in air, water, food or as dose absorbed/consumed b the organism -1-4 days (acute studies) |
| What does a graph for a dose-response study generally look like? | -s shaped curve -threshold: dose at which an effect can be detected |
| LD50 | -lethal dose that kills 50% of individuals -assesses relative toxicity of a chemical -compare to other tests -mice/rats represent mammals -pigeons/quail represent birds -trout represent fish -water fleas represent invertebrates |
| sublethal effects | harmful effects that a chemical might have |
| ED50 | effective dose that causes 50% of the population to display harmful but nonlethal effects |
| Toxic Substances Control Act of 1976 | -gives EPA authority to regulate many chemicals, though excluding food, cosmetics, and pesticides |
| Federal Insecticide, Fungicide, and Rodenticide Act of 1996 | manufacturer must demonstrate that a pesticide will not generally cause unreasonable adverse effects on the environment |
| How is the safe concentration of chemicals calculated for animals? | -LD50 value divided by 10 |
| How is the safe concentration of chemicals calculated for humans? | LD50/ED50 values from rats and mice divided by 1000 |
| chronic studies | -last from the time an organism is very young to when it is old enough to reproduce -examine long term effects of chemicals on survival and reproduction |
| epidemiology | field of science that strives to understand the causes of illness and disease in human and wildlife populations -retrospective and prospective studies |
| retrospective studies | monitor people who have been exposed to a chemical at some time in the past -group of exposed and group of unexposed -Bhopal, India Union Carbide factory explosion: 36000 kg of gas killed 17000 people and 100,000 ill people |
| prospective studies | monitor people who might become exposed to harmful chemicals in the future -eg. ask participants to track amount of alcohol they drink for 40 years and determine if habits are associated with health problems -synergistic interactions are a concern |
| synergistic interactions | two risks together cause more harm than one would expect based on their individual risks |
| What factors determine the concentrations of chemicals that organisms experience? | -routes of exposure -solubility of chemicals, bioaccumulation, and biomagnification -persistence |
| routes of exposure | the ways in which an individual might come into contact with a chemical -eg. air, food, soil, water |
| solubility | how well a chemical can dissolve in a liquid -water soluble: groundwater, surface water -oil/fat soluble: soil, fat tissues |
| bioaccumulation | -increased concentration of a chemical within an organism over time |
| process of bioaccumulation | -individual incorporates small amounts of a chemical from the environment into its body -chemical accumulates in fatty tissues and concentration increases over time |
| What factors does the rate of accumulation of a chemical in an organism depend on? | -concentration of the chemical in the environment -rate the animal takes up each source of the chemical -rate at which the chemical breaks down in the animal -rate at which it is excreted by the animal |
| biomagnification | increase in chemical concentration in animal tissues as the chemical moves up the food chain -each trophic level is exposed to higher concentrations of the chemicals from the food it consumes |
| persistence | how long the chemical remains in the environment |
| What factors determine a chemical's persistence? | -temperature -pH -whether the chemical is in water or soil -whether the chemical can be degraded by sunlight -whether the chemical can be broken down by microbes |
| How do scientists measure the persistence of a chemical | observe the time needed for the chemical to degrade to half its original concentration (half life) |
| environmental hazard | anything in our environment that can potentially cause harm -eg. pollutants, draining swamps, volcanoes |
| risk assessment | -identify a potential hazard and determine the magnitude of the potential harm |
| qualitative risk assessment | judgements based on perceptions but that are not based on actual data -eg. slowing down when driving down a wet driveway |
| perceived risk vs. actual risk | to manage our risks effectively, we need to ask how closely our perceptions of risk match the reality of actual risk |
| quantitative risk assessment | -risk = probability of being exposed to a hazard x probability of being harmed if exposed -the risk of a rare event that has a high likelihood of causing harm can be equal to the risk of a common event that has a low likelihood of causing harm |
| risk acceptance | -level of risk that can be tolerated -causes conflict between those willing to live with the risk and those who are not willing |
| risk management | -balance possible harm against other considerations -integrates data on risk assessment/analysis with a number of additional factors (economic, social, ethical, political) -regulatory -eg. arsenic levels in drinking water |
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