AAMC FL Practice Exam

What substance does the liver excrete?

1. Glucose

2. Bile

3. Oxygen

4. Urea

The correct answer is: Bile

The liver plays a crucial role in the digestive system and metabolic processes, one of its key functions is the production and excretion of bile. Bile is a digestive fluid that aids in the emulsification and absorption of fats and fat-soluble vitamins in the intestine. It is composed of bile salts, cholesterol, bilirubin, electrolytes, and water. The liver synthesizes bile from cholesterol and other substances, and it is then stored in the gallbladder until needed for digestion. While the liver does perform a variety of functions including glucose metabolism and the detoxification of various metabolites, it does not excrete glucose; instead, it regulates glucose levels in the blood. Oxygen is transported by the blood and is not produced or excreted directly by the liver. Urea, while produced in the liver through the urea cycle, is a waste product excreted by the kidneys, not directly by the liver itself. Therefore, among the listed options, bile is the correct substance that the liver excretes, highlighting its essential role in digestion and metabolism.