inhalation, ingestion, injection, absorption
Name four major routes of exposure
Toxins
________- endogenous substances biologically synthesized by living cells or microorganisms that are harmful to cells and tissues.
Poisons
exogenous agents that have adverse effects on biological system
TD50
predicted dose that would produce a toxic response in 50% of the population
LD50
predicted dose that would result in death in 50% of the population
ED50
predicted dose that would be effective or have a therapeutic benefit in 50% of the population
simple irritation to severe tissue destruction
upon inhalation (entry), chemicals can be exhaled or deposited in the respiratory tract This means direct contact with tissues in the upper respiratory tract thus causing
concentration of the chemicals in the air solubility of the substances in blood and tissues length & frequency of exposure respiration rate size of toxic particles conditions of the respiratory tract
factors affecting the inhalation of toxic chemicals
innocuous, destruction, blood, damage
In skin/eye absorption of toxic chemicals, it either cause local effect or enter systemic circulation. In local effect, it is usually relatively ______; redness, mild dermatitis more severe; skin tissue _______ In system circulation, many toxic substances can cross the skin barrier & get absorbed into _____ circulation produce ______ to internal organs
skin conditions (damage to the protective layer) nature of the toxic substances (organic/inorganic substances) eye contact (severe damage/effects even with short exposure)
factors affecting the skin absorption of toxic chemicals
direct ingestion, indirect ingestion, non-dietary ingestion
Three different types of ingestion
ability to diffuse and cross the cell membranes pH rate of dissolution gastrointestinal motility resistance to degradation
factors affecting the absorbance of toxic chemicals from gastrointestinal tract
intravenous injection intramuscular injection intraperitoneal injection intradermal injection subcutaneous injection
different injection routes:
duration and frequency of exposure routes of exposure interspecies & intraspecies variation environmental factors chemical combinations
factors affecting toxic response:
blood-brain, CNS
Increased concentration of aldehyde cross ______ barrier mediate most of the _____ effects of ethanol