Knowledge Check Solutions
1) pH - This is the correct answer.
The most important factor that determines absorption within the stomach is pH. Weak organic acids, which exist in a diffusible, nonionized and lipid-soluble form are readily absorbed in the high acidity of the stomach (pH 1-3). In contrast, weak bases will be highly ionized and therefore poorly absorbed.
2) Gastrointestinal tract, respiratory tract, and skin - This is the correct answer.
Environmental agents may be found in contaminated food, water, or air. As such, they may be ingested, inhaled, or present on the skin.
3) Small intestine - This is the correct answer.
By far, the greatest absorption takes place in the intestine. This is due to the neutral pH and the large, thin, surface area that allows easy penetrable by passive diffusion. Weak bases, weak acids, lipid soluble substances and small molecules effectively enter the body from the intestine. In addition, special carrier-mediated and active transport systems exist.
1) pH - This is the correct answer.
The most important factor that determines absorption within the stomach is pH. Weak organic acids, which exist in a diffusible, nonionized and lipid-soluble form are readily absorbed in the high acidity of the stomach (pH 1-3). In contrast, weak bases will be highly ionized and therefore poorly absorbed.
2) Gastrointestinal tract, respiratory tract, and skin - This is the correct answer.
Environmental agents may be found in contaminated food, water, or air. As such, they may be ingested, inhaled, or present on the skin.
3) Small intestine - This is the correct answer.
By far, the greatest absorption takes place in the intestine. This is due to the neutral pH and the large, thin, surface area that allows easy penetrable by passive diffusion. Weak bases, weak acids, lipid soluble substances and small molecules effectively enter the body from the intestine. In addition, special carrier-mediated and active transport systems exist.