What is the relationship between the structure and functions of the human small intestine?

The main function of the small intestine is to dissolve to monomers and assimilate biologically active substances – proteins (in the form of amino acids), fats (in the form of fatty acids and glycerol), carbohydrates (in the form of glucose). Accordingly, the inner surface of the small intestine is dotted with microvilli responsible for absorption and parietal digestion. In addition, the Wirsung duct opens into the small intestine, from which the enzymes necessary for the breakdown of nutrients represented by polymers are supplied.