Patient Care Technician (PCT) AAH Practice Exam

Which nutrient does the body primarily extract during digestion in the small intestine?

1. Water

2. Proteins

3. Fats

4. Carbohydrates

The correct answer is: Carbohydrates

The primary nutrient that the body extracts during digestion in the small intestine is carbohydrates. This process occurs mainly due to the action of enzymes, such as amylase, which break down complex carbohydrates into simpler sugars like glucose. The lining of the small intestine is equipped with microvilli, which significantly increases the surface area for absorption, allowing these simple sugars to be efficiently absorbed into the bloodstream. While proteins, fats, and water are also important substances that are processed in the small intestine, the breakdown and absorption of carbohydrates occur predominantly in this section of the digestive system. Proteins are primarily digested in the stomach and further in the small intestine, while fats undergo emulsification by bile before they can be absorbed. Water, though absorbed throughout the entire digestive tract, is not a nutrient that the body 'extracts' in the sense of complex breakdown and conversion into energy as carbohydrates are. This unique enzymatic process and the specialized absorption mechanisms make carbohydrates the key nutrient extracted during digestion in the small intestine.