Two major types of chemical substances that are broken down in chemical digestion are:
1. Carbohydrates: Carbohydrates are broken down by enzymes called amylases, which are secreted by the salivary glands and the pancreas. Amylases break down carbohydrates into simpler sugars, such as glucose, which can be absorbed by the body for use as energy or stored in the liver and muscles as glycogen.
2. Proteins: Proteins are broken down by enzymes called proteases, which are secreted by the stomach and the pancreas. Proteases break down proteins into amino acids, which can be absorbed by the body and used for a variety of functions, such as building new proteins, producing enzymes and hormones, and providing energy.