Describe the roles of bile and pancreatic juice in the digestion of food in the small intestine.

Bile is secreted by the liver and stored in the gallbladder. When chyme enters the small intestine bile is released into the duodenum where it emulsifies dietary fats, breaking large fat globules into small droplets. This increases the surface area available for pancreatic lipase to act on.

Bile also neutralises the acidic chyme that arrives from the stomach, raising the pH of the duodenal contents to a neutral or slightly alkaline range.

Pancreatic juice, secreted by the pancreas, contains the enzymes amylase, protease and lipase. These enzymes digest carbohydrates, proteins and fats respectively.

The alkaline/neutral pH created by bile is the optimum environment for the pancreatic enzymes to function efficiently.