Question

Each day, the pancreas produces up to 1.5 L of pancreatic juices that enter the duodenum via the pancreatic duct. The pancreatic juices consist of water, salts, bicarbonate ions, and digestive enzymes. Bicarbonate ion raises the pH of the acidic chyme from the stomach, stopping the active ity of pepsin and allowing the pancreatic and intestinal enzymes to function. The various pancre. atic enzymes and their substrates are listed in Table 10.2. Table 10.2 Various enzymes produced by the pancreas and their functions in the small intestine. Enzyme Function Pancreatic amylase Digests starch to form monosaccharides Trypsin, Chymotrypsin, Carboxypeptidase, Elastase Digests protein to form amino acids Digests triglycerides (fats + oils) to form glycerol Pancreatic lipase and fatty acids Digests nucleic acids (RNA+DNA) to form Ribonuclease, Deoxyribonuclease nucleotides CHECK YOUR UNDERSTANDING Triglycerides are lipids that form large globules in solution because they are or "water-fearing", molecules. As an emulsifier, bile disaggregates these large globules to increase the amount of for pancreatic lipase to conduct hydrolysis. 2. Describe how the cooperation of bile and lipase is similar to the HCI-pepsin interaction in the stomach. 3. What would be the consequences if the pancreatic juices did not contain HCO,? 4. Why do you think the salivary glands, liver, gallbladder, and pancreas are identified as accessory organs? THE DIGESTIVE SYSTEM 113

Answer 1

Ans 1- Triglycerides are a lipids that form large globules in solution because they are hydrophobic or water fearing molecule. As an emulsifier bile disaggregated this large globules to increase surface area for pancreatic lipase to conduct hydrolysis.

Ans 2 - Hydrochloric acid participate in protein digestion by supplying H+ which activates pepsinogen to pepsin as a precursor. Pepsinogen is secreted by chief cells in the gastric glands of the body and antrum of the stomach. Proteins are broken down in to fragments of various sizes, Like- peptides or amino acids by pepsin. Same as bile acid digests fat globules . It is emulsifier of lipid . Emulsification is not digestion but it is necessary to increase the surface area of fat to make availability for digestion by lipase. Which cannot access the inside of lipid droplets absence of bile acid.

Ans 3 - Bicarbonate is neutralised the gastric acid containing the food which is passed into the duodenm which allowing for effective enzyme at exchange if pancreatic juice cannot produce adequate bicarbonate so it may not rich in duodenm

Ans 4 - The salivary gland, liver, gallbladder and pancreas are known as accessory organ because it can participate with the digestion but it is not part of digestion track they are secrets certain hormones and enzymes to help in digestion.