DIGESTION IN DUODENUM

 

Duodenum is the first part of small intestine that consists of about 12 inches or so. The pyloric sphincter at the stomach open to allow a small amount of chyme at a time to pass into the duodenum. The secretion of liver and the pancreas pour into the duodenum with the arrival of food here.

 

       PANCREATIC JUICE

       It is secreted by the pancreas and brought to the duodenum by pancreatic duct. Pancreatic juice is slightly alkaline with a pH of about 8 and thus partially neutralizes the acid contents emerging from the stomach. The pancreatic juice contains several important enzymes.

        Amylase or Amylopsin

        It is a starch digesting enzyme and is similar to salivary amylase in enzymatic action. However, it is more active in hydrolyzing the polysaccharides to maltose and even glucose.

          Lipase

          This enzyme is responsible for the hydrolysis of fats. It catalyzes the hydrolysis of fats to neutral fat in part to its di-and mono-glycerides as well as to glycerol and fatty acids. Its also causes esters to convert them to their acid and alcohol components.

         Trypsinogen And Other Protein Digesting Enzymes

           Several protein-digesting enzymes are present in the pancreatic juice as inactive precursors which are then activated. Enzyme trypsinogen which is activated to trypsin. Trypsin breaks proteins into polypeptides and peptides. Thus a mixture of peptides and amino acids is formed due to the activity of various protein-digesting enzymes.

 

           BILE

         Bile is greenish fluid which is produced in liver and stored in gall bladder which lies between the lobes of the liver. It is poured into the duodenum through bile duct. Bile has no enzyme however it helps in the digestion of facts.

         

            Bile is composed of water, sodium bicarbonate excess of calcium, certain breakdown products of hemoglobin from worn-out red blood cells and some other wastes from the liver. Water acts as a solvent while sodium bicarbonate helps in changing the pH.

          

            Bile takes part in lipid digestion and absorption by increasing emulsification and solubilization of lipids including the fat soluble vitamins and the fatty fats formed in fat digestion.

 

        GLANDS IN THE DUODENUM WALL

          There are certain glands embedded in the wall of the duodenum that produce mucus, water and sodium bicarbonate. These substance help in the lubrication of food, protection of lining and maintenance of pH to 7.8.