In the small intestine most by the wall of the small intestine into the blood stream and carried to the different body parts where they fulfil their functions: amino acids to be formed into proteins glucose and fats to be used as energy sources of the digestive reactions and the absorption of nutrients take place. The inner wall has finger-like structures that secrete (produce) a variety of enzymes that react with feed proteins, starch and fats to digest these components into their smallest units. Proteins to amino acids, starch to glucose and fats to fatty acids. These are absorbed by the wall of the small intestine into the blood stream and carried to the different body parts where they fulfil their functions: ammino acids to be formed into proteins, glucose and fats to be used as energy sources.