AAMC FL Practice Exam

Where does fat digestion primarily occur?

1. Mouth

2. Stomach

3. Small intestine

4. Pancreas

The correct answer is: Small intestine

Fat digestion primarily occurs in the small intestine due to the presence of bile salts and pancreatic lipase. When fats are consumed, they first undergo emulsification by bile acids produced by the liver and stored in the gallbladder. This emulsification process breaks down large fat globules into smaller droplets, increasing the surface area for enzymes to act upon. Once emulsified, pancreatic lipase, an enzyme secreted by the pancreas, interacts with the fat droplets to break down triglycerides into free fatty acids and monoglycerides. This enzymatic action is crucial as it allows for the efficient absorption of these breakdown products through the intestinal wall into the bloodstream. The mouth and stomach do have minimal fat digestion; however, the primary enzymatic processes for fat digestion occur in the small intestine. The pancreas plays a vital role by producing enzymes such as lipase and sending them to the small intestine, but it does not directly digest fats itself. Thus, the small intestine is the key site for the digestion and absorption of fats in the digestive system.