Trypsin, chymotrypsin, and carboxypeptidase are pancreatic proteolytic enzymes that are secreted as zymogens, or inactive precursors of the enzymes, and activated in the digestive canal lumen. Digestion enzymes and bicarbonate are two secretory products found in pancreatic juice that are essential for effective digestion. The exocrine acinar cells produce and secrete the enzymes, whereas the epithelial cells lining tiny pancreatic ducts secrete bicarbonate. Protein digestion begins in the stomach with pepsin, but the pancreatic proteases do the majority of the work. The pancreas produces many proteases, which are released into the small intestine lumen. Trypsin and chymotrypsin are two primary pancreatic proteases that are produced and packaged as the inactive proenzymes trypsinogen and chymotrypsinogen in secretory vesicles. Triglyceride, or neutral lipid, is a key component of dietary fat. A triglyceride molecule cannot pass through the intestinal mucosa directly. Instead, it must be broken down into two monoglycerides and two free fatty acids. Pancreatic lipase, which is transported into the gut lumen as a part of pancreatic juice, is the enzyme that executes this hydrolysis. Starch, a storage form of glucose in plants, is the main dietary carbohydrate for many animals. Pancreatic secretions are the main source of amylase in all species, while some animals, including humans, have amylase in their saliva.