Chapter 8: Toxicology Flashcards
health
a state of complete physical, mental, and social well-being
disease
an abnormal change in the body’s condition that impairs physical or psychological function
what plays a role in morbidity and mortality?
diet and nutrition, infectious agents, toxic chemicals, genetics, trauma, and psychological stress
morbidity
illness
mortality
death
toxins
chemicals, smoking, lead
infectious agents
bacteria, protozoa, viruses
trauma
accidents
radiation
ultraviolet (sun), ioniziong
pollution
air, noise, water
life expectancy increases as
infant mortality decreases
disability-adjusted life years (dalys)
combine premature deaths and loss of healthy life resulting from illness or disability
heart disease
may become the leading source of disability and disease worldwide by 2020
global cancer
rates will increase by 50% by 2020
diabetes
increasing, 1/3 of children born in north america today will develop diabetes in their lifetime due to poor diet and little exercise
psychological conditions
increase their share of global disease burden from 10% currently to 15%, depression will be the second largest cause of years lived with disability, tobacco related lung disease, biggest cause of death worldwide
communicable diseases
still responsible for about 1/3 of all disease-related deaths. majority in countries with poor nutrition, sanitation, and vaccination
pathogens
disease-causing organisms, including: viruses, bacteria, protozoans, parasitic worms including flukes
greatest loss of life in a single year from a pathogen
flu epidemic, h1n1, malaria
emergent disease
one never known before or one which has been absent for at least 20 years, bird flu, ebola fever, hiv
ecological diseases
animal epidemics
white nose syndrome
ecological disease, in bats due to fungus
california sea lions
ecological disease, herpes 1 virus spread to them from human sewage
dermo
ecological disease, parasite of oysters, spreading rapidly along the east coast due to climate warming
conservation medicine
examines how environmental changes threaten the health of humans and natural communities
antibiotics
chemicals that kill or inhibit the growth of bacteria
antibiotic resistance
mutation and selection create drug resistant stains or conjugation transfers drug resistance from one strain to another
toxicology
study of poisons and their effects on living systems
toxic
known poisons that damage or kill cells/tissues, can be general or very specific, often harmful even in dilute concentrations
hazards
dangerous but not toxic, flammable, explosive, irritant, acid, caustic
ectotoxicology
interactions, transformation, fate, and effects of natural and synthetic chemicals in the biosphere
allergens
toxin, substances that activate the immune system
antigens
substances that are recognized as foreign by white blood cells and stimulate the production of specific antibodies, act indirectly by binding to other materials so they become antigenic
immune system depressants
toxin, pollutants that depress the immune system
endocrine disrupters
toxin, disrupt normal hormone functions
environmental estrogens
endocrine disrupters, environmental contaminants which cause reproductive problems in animals even at low doses
neurotoxin
toxin, metabolic poisons that specifically attack nerve cells; most are extremely toxic and fast acting
heavy metals
neurotoxin, kills nerve cells
anesthetics and chlorinated hydrocarbons
neurotoxin, disrupts nerve cell membranes
organophosphates and carbamates
inhibit signal transmission between nerve cells
mutagens
toxin, agents that damage or alter genetic material, can lead to birth defects or tumors
teratogens
toxin, specifically cause abnormalities during embryonic growth and development, alcohol-fetal alcohol syndrome
carcinogen
toxin, substances that cause cancer, cancer is 2nd leading cause of death, 1/2 males, 1/3 females in the US will have cancer
solubility
one of most important characteristics in determining the movement of a toxin, dissolve readily in water or oil
water soluble compounds
move rapidly through the environment and have ready access to cells via tissue fluid
fat soluble compounds
need a carrier to move through the environment, once inside the body they penetrate tissues easily and cross cell membranes. stored in body fat, persist for years
airborne toxins
generally call more illness than other exposures, lining of lungs easily absorb toxins
bioaccumulation
selective absorption and storage of toxins, dilute toxins in the environment can build to dangerous levels inside tissues
biomagnification
toxic burden of a large number of organisms at a lower trophic level is accumulated concentrated by a predator at a higher trophic level: DDT
flame retardants (PBDE)
found in humans and other species everywhere, harm children’s reproductive and nervous systems, persistent organic pollutants
phthalates
found in plastics mimic estrogen and are linked to reproductive abnormalities and reduced fertility, persistent organic pollutant
antagonistic reaction
one material interferes with the effects or stimulates the breakdown, of other chemicals
additive reaction
effects of two chemical occurring together are added to one another
synergistic reaction
one substance exacerbates the effect of the other
metabolic degradation
in mammals, the liver is the primary site of detoxification of both natural and introduced poisons, sometimes harmless compounds are broken down into harmful products
excretion
breathing and urinating eliminate the effects of waste products and environmental toxins
tissues and organs often have mechanisms for damage repair …
cellular reproduction, any irritating agent can be potentially carcinogenic because the more times that the cells divide the greater the chance they will mutate while copying DNA which can lead to cancer
animal testing
most commonly used and widely accepted toxicity test is to expose a population of laboratory animals to measured doses of specific toxins
LD50
dose at which 50% of the animal testing population dies
moderate toxin
takes about 1 g/kg of body weight to produce a lethal dose, very toxic materials require 10% of that amount, extremely toxic materials require 1%
acute effects
caused by a single exposure and results in an immediate health problem
chronic effects
long-lasting, perhaps permanent, can be result of single large dose or repeated smaller doses
delaney clause of the US food and drug act
“no reasonable harm” less than one cancer for every million people exposed over a lifetime, for addition of carcinogens to food and drugs
risk
possibility of suffering harm or loss
risk assessment
scientific process of estimating the threat that hazards pose to human health, not rational, risk identification, dose response assessment, exposure appraisal, risk characterization
risk acceptance
people tolerate high probability of an occurrence if the harm is low, great harm acceptable at very low frequency, 1/100,000 chance of dying is threshold for chancing behavior; environmental protection agency 1/1 million is acceptable for environmental hazards
in setting standards for health policy consider…
combined effects of exposure, different sensitivities, effects of chronic and acute exposure
