Digestive-Absorptive Processes
Because the organs and the processes of digestion and absorption may have already been studied in anatomy, physiology, and chemistry courses, this section focuses primarily on the nutrients that form the substrates, the specific enzymes involved in the hydrolysis reactions, the products that are formed by the digestive process, and the mechanisms of absorption. One should remember, however, that foods are eaten in a variety of forms and combinations; cooking and other processing methods may, therefore, begin the breakdown of complex compounds, such as starch and collagen (protien), before foods are ingested.
Although the general aspects of digestion and absorption are discussed separatel, the are considered together for individual nutrients. It is useful to visualize the process as a whole and to focus on the transforma tions that take place in three sequential sites of the gastrointestinal tract: in the lumen (luminal phase), in the lipoprotein membrane of the microvilli (brushborder phase) , and in the epi thelial cell (intracellular phase) . For a review of the structure of the gastrointestinal tract.
Because the organs and the processes of digestion and absorption may have already been studied in anatomy, physiology, and chemistry courses, this section focuses primarily on the nutrients that form the substrates, the specific enzymes involved in the hydrolysis reactions, the products that are formed by the digestive process, and the mechanisms of absorption. One should remember, however, that foods are eaten in a variety of forms and combinations; cooking and other processing methods may, therefore, begin the breakdown of complex compounds, such as starch and collagen (protien), before foods are ingested.
Although the general aspects of digestion and absorption are discussed separatel, the are considered together for individual nutrients. It is useful to visualize the process as a whole and to focus on the transforma tions that take place in three sequential sites of the gastrointestinal tract: in the lumen (luminal phase), in the lipoprotein membrane of the microvilli (brushborder phase) , and in the epi thelial cell (intracellular phase) . For a review of the structure of the gastrointestinal tract.
