Principle objective of this article is to explain Fundamentals of Human Digestion. Digestion happens down the digestive tract. The human digestion is very much a long passageway. Digestion is some sort of two-step process. First step should be to crush the food directly into smallest possible particles. Second step should be to mix crushed food with digestive enzymes. The digestion has four main parts. Mouth and throat are the first the main digestive system. Esophagus joins the throat using the stomach. Esophagus along with stomach is the next the main digestive tract. Small intestinal tract, liver, pancreas and gall bladder form the hub with the digestive system.