AAMC FL Practice Exam

In which part of the digestive system does carbohydrate digestion begin?

1. Mouth

2. Stomach

3. Small intestine

4. Large intestine

The correct answer is: Mouth

Carbohydrate digestion begins in the mouth due to the action of salivary amylase, an enzyme produced by the salivary glands. When food is chewed, salivary amylase starts breaking down starches into simpler sugars, such as maltose and dextrins. This enzymatic activity occurs early in the digestive process, highlighting the mouth's role in initiating digestion. In the stomach, while gastric juices aid in overall digestion, the acidic environment disrupts starch breakdown, and salivary amylase becomes inactive. The small intestine is crucial for the absorption and further digestion of carbohydrates, but the initial enzymatic action occurs in the mouth. The large intestine primarily focuses on the absorption of water and electrolytes, and the fermentation of certain carbohydrates by gut bacteria, but it does not play a significant role in the digestive process of carbohydrates.