Mechanisms for Toxic Materials

There are three types of defenses against toxic materials internal, antidotal, and external. Three things can happen once a chemical is taken into the body metabolism, storage, and excretion. Internal defenses are the ability of the body to get rid of a toxic material, sometimes referred to as metabohsm. The body normally excretes waste materials through the feces or urine. Additionally, women can also excrete through the ova and breast mUk. In these instances, the excretions from the mother represent exposure to the offspring. 

Toxic materials that enter the body cannot always be excreted and may be stored in the fatty tissues. Examples include the organochlorines, DDT, PCBs, and chlor-dane. When a person loses weight, for whatever reason, toxic materials that have been stored in the fatty tissues are released back into the body as the levels of fat decrease. When this occurs, the body is reexposed to the chemicals and illness can occur. Chemicals that cannot be excreted from the body may also be bound by blood proteins and stored in the blood. Lead is an example of a material that cannot be excreted from the body and is stored in the bones. 

Polarity has an effect on the body s ability to excrete toxic materials. If a poison is polar, it is usually soluble in water, because water is also polar and is more easily removed from the body. The body also has a system of converting nonpolar compounds so that they can also be removed however, the body cannot convert all nonpolar compounds. Therefore, some poisons are difficult to convert and may stay 

Organophosphate pesticides Methanoi or ethylene glycol Nitrites 

Amyl nitrate, sodium nitrate, sodium thiosulfate Atropine, pralidoximine IV ethanol, hemodialysis Oxygen, methylene blue Oxygen 

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Defense Mechanisms for Toxic Materials Toxic Elements Toxic Salts Hydrocarbons Hydrocarbon Derivatives Alkyl Halides Amines Alcohols Aldehydes Organic Acids... 

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