Kaplan Nursing Entrance Practice Exam

What type of digestive enzymes are present in saliva?

1. Proteases

2. Amylases

3. Lipases

4. Nucleases

The correct answer is: Amylases

Saliva primarily contains amylases, which are digestive enzymes that play a key role in breaking down carbohydrates. Specifically, salivary amylase, also known as ptyalin, initiates the process of starch digestion in the mouth by hydrolyzing the alpha bonds in starches, converting them into simpler sugars like maltose and dextrin. This is significant because it starts carbohydrate digestion before the food reaches the stomach, facilitating further breakdown and absorption in the intestines. While proteases, lipases, and nucleases are important digestive enzymes, they are not typically present in saliva or are present in very minimal amounts. Proteases are primarily found in the stomach and intestines where they aid in protein digestion. Lipases, which break down fats, are mainly secreted by the pancreas and also act in the intestines. Nucleases digest nucleic acids, but they are primarily active in the intestinal tract. Thus, the presence of amylases in saliva is the correct and most relevant information regarding digestive enzymes in that context.