Digestive System Human digestive system is a pipe-like structure which starts from the mouth and ends in anus. In between there are some organs like stomach, small intestine and large intestine where digestion of foods occurs. There are some glands which help in digestion e.g. salivary gland, liver and pancreas. Digestion means breaking down the food into those molecules that can be absorbed by the body.so if we divide food into the macro categories they will be 1)carbohydrate, 2)protein and 3)fat. In carbohydrates, there can be these types of bonds – Starch and glycogen : starch and glycogen are storage polymers of glucose in plants and animals respectively. In starch and glycogen the glucose molecules are bonded by glycosidic bonds ( alpha 1-4 glycosidic bond and alpha 1-6 glycosidic bond). Our body cannot absorb the big molecules as starch, so it has to be broken to free glucose molecules for absorption. Amylase enzyme is released by the salivary gland and pancreas can break thes