Bodily Defenses Image Map

Toxic substances are everywhere. The body is not only exposed to toxic chemicals in the environment, but also some toxins are produced in the body through normal body chemical reactions.

How can our bodies cope? This module explains some of the ways that animals and humans combat and eliminate toxic chemicals. The organ systems involved include the lungs, the skin, and the digestive tract, but two organs are especially important: the liver and the kidneys.

We call the process of eliminating toxins, "detoxication" or "detoxification," which is the opposite of "intoxication." Different tissues detoxify in varying ways.

  • Lungs can detoxify by removing gases (gas anesthetics are removed from the body by the lungs). 
  • Skin can detoxify by reducing the penetration of toxic substances (toxins in water don't get in through the skin well; however, toxins in oils do penetrate easily). 
  • Digestive System can detoxify by eliminating toxic foods, by either vomiting or diarrhea.
  • Kidneys detoxify by secreting toxins or filtering toxins out of the blood into urine.
  • Liver detoxifies by changing the chemical nature of many toxins.

Kidney and liver are especially important. They are discussed separately because they work in different ways.


Upon completing this unit, the student should be able to:

  • Explain why detoxication systems are needed in the body
  • Identify the systems in the body that have detoxication functions and  summarize how they perform their detoxifying actions

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