1. The target organ is always the site of the highest concentration of the chemical.
A) True
B) False
2. At low doses, 2,3,7,8-tetrachlorodibenzo(p)dioxin (dioxin) has been postulated to inhibit certain types of estrogen-dependent cancers. This is an example of:
A) potentiation
B) dispositional antagonism
C) hormesis
D) chronic toxicity
E) none of the above
3. Which of the following is NOT an outcome of acute toxicity testing:
A) identification of target organs
B) identification of the LD50
C) identification of species differences
D) provide guidance for the selection of doses for subsequent testing
E) provide guidance for selection of the route of exposure for subsequent testing
4. For some toxicants, oral toxicity is actually increased by diluting the dose. This is probably due to:
A) the lack of competitive inhibition of xenobiotic transporters due increased dosage volume
B) more rapid stomach emptying induced by increased dosage volume - which leads to more rapid absorption in the duodenum
C) increased water solubility of lipid soluble compounds due to increased dosage volume
5. The toxicity of a compound is directly due to the amount of the toxicant that is:
A) bound to plasma proteins
B) unbound to plasma proteins
C) bound to tissue (such as liver or kidney)
D) stored in a depot (such as fat or bone)
E) metabolized
6.Which of the following is NOT a characteristic of the blood-brain barrier?
A) the brain capillary endothelial cells are tightly joined
B) the brain capillary endothelial cells are insensitive to lipid-soluble toxicants
C) the brain capillary endothelial cells contain ATP-dependent transporters that transport some chemicals back into the blood
D) the brain capillaries are surrounded by astrocytes
E) the protein concentration in the interstitial fluid is much lower than that of other body fluids
7. Ammonia (pH 11) would be expected to be concentrated and excreted in breast milk.
A) True
B) False
8. Exposure to a toxicant that induces CYP450 can lead to a situation in a patient wherein larger doses of a particular pharmaceutical must be administered to achieve a therapeutic blood level (due to increased metabolism of the pharmaceutical). This "situation" is known as:
A) induction
B) tolerance
C) inhibition
D) knockout
E) none of the above