Clinical Chem Toxicology

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