IMAT 2018 Q34 [Digestive System]

Which of the following structures make a solution that can raise the pH in the digestive system of a healthy human?

  1. gall bladder
  2. pancreas
  3. stomach

A. 2 and 3 only
B. 1 and 2 only
C. 1 only
D. 2 only
E. 3 only

The answer to this question is choice D, only the pancreas is the correct structure for this question.

Let’s rationalize each of the structures given:

  1. Gallbladder: Immediately, this is already a wrong consideration regardless of what is actually stored in the gallbladder. Why? If you read the question again, it said “…make a solution”, which is not applicable to the gallbladder in the first place. Please be reminded of the main function of the gallbladder, which is to simple STORE bile and NOT produce it. The production of bile itself is the task of the liver. Thus, even though bile is alkaline in nature, the fact that the gallbladder does not produce it eliminates this from your consideration.
  2. Pancreas: This is the only correct structures out of those given. This is because the pancreas has the ability to secrete bicarbonate in response to the acidity it receives from the stomach, in order to neutralize this acidity. In more detail, secretin stimulates the secretion of bicarbonate within the pancreatic juices that are secreted into the small intestine. Therefore, since bicarbonate is alkaline in nature, the pancreas is the only correct choice.
  3. Stomach: This is an incorrect consideration, attributing it to the fact that the gastric environment is very acidic. This acidity is due to the secretion of HCl or hydrochloric acid by the parietal cells of the stomach. This acid component is the most significant part of gastric juices that aid in digestion.

Thus, the only correct structure among all the choices that directly produces an alkaline solution is the pancreas.