The process through which complex food substances is broken down physically and chemically into simpler food substances that can be absorbed by body cells.
However, small molecules like those of vitamins, mineral salts and water are directly absorbed into the bloodstream without undergoing digestion.
Digestion occurs in the mouth, stomach, duodenum and ileum.
There are glands also associated to the digestive system. These include the pancreas, gallbladder, salivary glands.