Eating is only the first step in getting nourishment from the foods we consume. Everything that we eat must be broken down before it can be utilized by the body. This is the digestive system's purpose. The digestive tract provides the body with important nutrients available in the foods we eat. The digestive organs, liver, gallbladder and pancreas, introduce vital ingredients for the proper digestion of food. Digestion begins with the smell of food when we are hungry, which triggers the secretion of digestive enzymes in saliva, even before the first bite. Chewing food well increases the secretions. If small enough, some nutrients can be absorbed trough the mucous membranes of the mouth directly into the bloodstream. Once swallowed, the food is push through the esophagus by the rhythmic action of his muscles. When it reaches the stomach, the food is churned and mixed with enzymes. The stomachs high acid levels destroy germs and catalyze further digestive processes. Foods with high fat content take the longest to digest, carbohydrates the least. Food enters the small intestine, where it is broken down further and the nutrients are absorbed into the bloodstream. Bile, manufactured in the liver and stored in the gallbladder, is released into the intestine during a meal. Bile helps break down fats, and eliminate some waste from the liver via the digestive track. The pancreas provides many enzymes necessary for the final breakdown of food. Excess particles are pushed through the intestines to be expelled.