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11/14/12 Chapter 8 guide: Outline: 8.1 describe health & disease & how the global disease burden is now changing 8.2 summarize the principles of toxicology 8.3 discuss the movement, distribution, & fate of toxins in the environment 8.4 explain ways we evaluate toxicity & risk 8.5 relate how we establish health policy 8.1 Environmental health Global disease are decreasing such as infectious decease & while internal health problems increase Emergent diseases increases as we come into contact with new environments (sharing germs) Conservation medicine combines ecology with health care Health- well-being of an individual mentally, socially & physically Disease- impairment of body function mentally, socially & physically Morbidity- illness Mortality- death Environmental health- external (outside) factors that causes diseases such as environment & nature The global disease burden is changing Although pollution is increasing on the brighter side there have been significant progress in disease treatments Disability- adjusted life years (DALYs)- measure of disease burden, premature deaths & loss of healthy life cause of illness or disability Chronic obstructive lung diseases (COPD) Infectious & emergent diseases still kill millions of people Pathogens- disease-causing organisms Protozoans- single-celled animals Severe acute respiratory syndrome (SARS) Emergent diseases- not previously learned or have been absent for 20years Conservation medicine combines ecology & health care- Ecological diseases- suffering of new & devastating diseases (widespread epidemics) Conservation medicine- understand how environmental threatens our well-being & those organisms that live in nature & that we depend on for services Resistance to drugs, antibiotics, & pesticides is increasing Diseases thought to be wiped out come back even stronger & insects or organisms that carry them because of developing resistance to cures Humans cause evolution to develop faster when trying to extinguish all pesticides with harmful toxins What would better health cost? Better health cost millions of dollars that’s why there are funds that provide donations to developing countries Africa has a hard time with affording health care & a healthy environment 8.2 Toxicology Many toxins harmful in weak liquid concentrations (billionth or trillionth causes irreversible damages) Toxins found in home in wide variety of products Chemicals disrupt hormonal functions harmful in growth developments even in small doses Toxins- poisons How do toxins affect us? Allergens- substances that activate the immune system Antigens- recognized as foreign by white blood cells stimulate production antibodies protects body foreign diseases Sick building syndrome- poorly ventilated indoor air (causes headaches & allergies) Endocrine disrupters- chemicals that disrupt hormonal functions Neurotoxins- special class of metabolic poisons that specifically attack nerve cells (neurons) Mutagens- chemicals or radiation causes changes in genetic material (DNA) Teratogens- factors or chemicals causes problems during pregnancy growth Fetal alcohol syndrome- cluster of symptoms that happens throughout a child’s life (behavior problems) Carcinogens- substance cause cancer Cancer- out of control cell growth that causes tumors (2nd leading cause of death) How do diet influence health?- 60% adults in U.S. are considered overweight (300,000 links to death) Eating more causes health problem & type of food Eat healthy & less saves people from obesity 8.3 movement, distribution, & fate of toxins Solubility & mobility determine where & when chemicals move through the environment & in our bodies Persistent materials can move concentrated toxic materials through food web to top predators Synergistic interactions increase effects of combined toxins far beyond any single substance Solubility & mobility determine where & when chemicals move Two chemical type dissolve in water or in oil (readily access to body cells) Stays very long time in body Exposure & susceptibility determine how we respond Human breath more in any other activity such as eating etc. making them more prone to toxins & death Bioaccumulation & biomagnification increase concentrations of chemicals Bioaccumulation- selective absorption & storage of a great variety of molecules Biomagnification- toxic burden on large # organisms lower trophic level then concentrated in a predator in a higher trophic level Persistence makes some materials a greater threat Substances that are resistant to degradation Persistent organic pollutants (POPs)- top toxic concentration in top predators (humans, bears, sharks, etc.) Body burden- persistent toxins in our bodies (water, diets, & surroundings) Chemicals interactions can increase toxicity Synergism- one substances makes the effects of another worst Example smoking accelerates the cause of cancer Metabolic degradation & excretion eliminate toxins Toxins can come out of the body through waste Repair mechanisms mend damage Cells that are damaged regularly can repair damages although if frequently it may lose that ability to repair 8.4 Toxicity & risk assessment Toxicology dose makes the poison, amount, timing, exposure determines response Fear proportion but ignores hazards despite effects Substances or factors disruption of developments at low doses We usually test toxins on lab animals Testing population under controlled conditions LD50- test whether 50% of the test population is sensitive There is a wide range of toxicity Toxics reside in food can even kill a mouse imagine what it’s doing to our bodies Acute & chronic doses & effects differ Acute effects- single exposure to toxin & cause immediate health crisis Chronic effects- cause of single dose toxic substances or continuously Detectable levels aren’t always dangerous Toxins are found scattered everywhere in food samplings (maybe insignifigant) Low doses can have variable effects Either good or bad effects, helps or hurts you Protects against cancer or causes health problems Some symptoms can be erroneous When a person describe how sick they are you begin to feel sick as well (no evidence though) Risk perception isn’t always rational Risk- possibility of suffering harm or loss Risk assessment- process estimate hazards pose to human health Risk acceptance depends on many factors Weighing does the benefits outweigh the risks 8.5 establishing health policy Difficult evaluate multiple risks & benefits simultaneously Setting health standards consider combined exposures, difference btwn chronic & acute exposure Precautionary exposure- show substance is not dangerous before they are introduced