Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Digestive (GI) Physiology 1. What are the three main simple sugars? Glucose, fructose, and galactose 2. What is maltose made of? Glucose + glucose 3. What is lactose made of? Glucose + galactose 4. What is sucrose made of? Glucose + fructose 5. What is a polysaccharide (complex carbohydrate) made of? The joining of many monosaccharides and disaccharides. 6. Where are complex carbohydrates stored, and in what form? They are stored as glycogen in the liver 7. What do complex carbohydrates break down into? Glucose 8. What is the storage form of carbohydrates in plants called? Starch 9. Can we use starch? Not directly. We convert it to glucose, which is the form we can use. 10. What Organ secretes Glucagon? Pancreas 11. What organ secretes insulin Pancreas 12. What does Glucagon do to blood glucose levels? Raises blood glucose 13. What does insulin do to blood glucose levels? Lowers blood glucose levels 14. When does the pancreas release glucagon? When blood sugar levels fall too low, especially between meals 15. When does the pancreas release insulin? When blood sugar levels are too high, especially after meals 1 16. What is glycogenolysis? The breakdown of glycogen into glucose 17. What is glycolysis? The breakdown of glucose to pyruvic acid, and ATP is formed. 18. What is the difference between glycogenolysis and glycolysis? Glycogenolysis is the breakdown of glycogen into glucose. Glycolysis is the breakdown of glucose into ATP 19. When is Insulin released? When there are high blood glucose levels 20. What does insulin do to decrease blood glucose levels? Insulin takes the glucose into cells that need it for glycolysis to produce ATP 21. How do glucagon and insulin work together? To keep blood glucose levels at a stable level. 22. What other two simple sugars can be broken down into pyruvate and ATP? Fructose and galactose 23. During glycolysis, what energy molecule is used up, which needs to be replaced, and how do we do that? NAD is used up because it is reduced to NADH. We need to oxidize it back into NAD by anaerobic or aerobic respiration. 24. How many molecules of ATP are used during glycosis? 2 ATP molecules 25. How many ATP are made during glucolysis? 4 are made 26. What is the net gain of ATP in glycosis? 2 ATP molecules 27. What does a cell do immediately after finishing glycolysis? Aerobic or anaerobic respiration, depending on the availability of oxygen. 2 28. In what part of a cell is aerobic respiration performed? In the mitochondria 29. In what part of a cell is anaerobic respiration performed? In the cytoplasm 30. How many ATP result from Aerobic Respiration? 6 31. How many ATP result from anaerobic respiration? 2 32. What molecule is regenerated during respiration, and what is it used for? NADH is oxidized to NAD, so glycolysis can continue. 33. Where is Aerobic Respiration performed? Mitochondria 34. Positives of making ATP this way: 35. Negatives of making ATP this way: Can make a lot of ATP Takes a long time to Make ATP because we need oxygen to make it. 36. What are the waste products of aerobic respiration? Waste products are CO2 and H2O (we exhale them) 37. Where is Anaerobic Respiration performed? Cytoplasm 38. Positives of making ATP this way: 39. Negatives of making ATP this way: 40. What is the waste product of anaerobic respiration? 41. Under what conditions will pyruvate use anaerobic respiration? We can make it FAST. That it does not make much ATP, and we deplete the reserves quickly. Waste product is lactic acid In muscle during strenuous workouts when oxygen becomes deficient. 3 42. What enzyme takes the hydrogen from NADH during anaerobic respiration? Lactate dehydrogenase 43. Where does the hydrogen ion go after it is removed from NADH? It is placed on pyruvate, which turns it into lactate. 44. How is lactic acid formed? From lactate 45. What does lactic acid build-up in muscles do to the body? Causes muscle aches and fatigue 46. How do you deactivate lactic acid? 48. Can we store ATP? Add oxygen to it. It goes back to being pyruvate plus water. Soak them in warm water or use ultrasound to increase circulation. Oxygen will be able to turn the lactic acid into pyruvate and water. No 49. What can muscles do to store energy for future periods of activity? Muscles convert excess ATP to creatinine phosphate, which can be stored. 50. When is creatinine phosphate broken down to produce ATP? When the small reserves of ATP existing in a cell are used first. 51. When do we use aerobic respiration? Resting and running a marathon (whenever we can breathe easily enough to talk). 52. How a marathon runner would make sure he or she would enough readily available energy for the muscles? By eating a lot of carbohydrates over a twoday period before the marathon (carbohydrate loading). 53. When do we use anaerobic respiration? Sprint running (whenever we cannot breathe easily enough to talk). 54. What is gluconeogenesis? generation of new glucose from lactate, glycerol or amino acids 47. What can you do to make muscle aches go away? 4 55. If we do not have enough glucose in our body, what do we break down to make glucose? -Proteins (muscles) 56. What are the two main mechanisms to keep blood glucose levels from dropping too low? -Gluconeogenesis 57. What is the function of saliva? To clean the oral cavity and moisten the food. 58. What enzyme does saliva have? Amylase 59. What two things does amylase break down? polysaccharides and disaccharides 60. Give an example of a polysaccharide Starch 61. What is the function of mucous in the saliva? Helps soften the food and form it into a bolus 62. What coordinates the mechanism for swallowing? medulla oblongata and pons 63. What initiates the swallowing reflex? touch receptors in the pharynx are stimulated when the bolus of food is pushed to the back of the mouth 64. Where does protein digestion begin? In the stomach 65. Where are mucous cells located? In the stomach 66. What do they secrete? Mucous 67. What is the function of this secretion? Protect the stomach lining from being digested 68. What two things do the parietal cells of the stomach secrete? Hydrochloric acid (HCl) and intrinsic factor - Breakdown of glycogen (glycogenolysis) 5 69. What is the function of intrinsic factor? Enables the absorption of vitamin B-12 70. What is vitamin B12 used for? To make RBC’s (red blood cells) 71. What are the three functions of HCl? 1) Cuts pepsinogen into pepsin, which digests proteins 2) Kills many microorganisms that are ingested with the food. 3) Denatures proteins. It does not break down food. 72. Does it break down food? 73. What do the chief cells secrete? Pepsinogen 74. What does pepsin do? Breaks down proteins to the individual amino acids 75. What do G cells secrete? Gastrin 76. What three things protect the stomach lining? Mucous, bicarbonate, prostaglandins 77. What is the term used to describe low gastric acidity? Hypochlorhydria 78. Name 5 diseases associated with Hypochlorhydria Asthma, coeliac disease, eczema, osteoporosis, and pernicious anaemia 79. What is the term used to describe high gastric acidity? Hypochlorhydria 80. Name 3 conditions associated with hypochlorhydria Heartburn, gas, ulcers 81. What are the symptoms of hypochlorhydria? Causes malabsorption and related symptoms (gas, diarrhea, anemia) 82. Why does anemia result from malabsorption problems? Folic acid, vitamin B12 and iron will not be absorbed if there is too little acid 6 83. What is the function of the Duodenum? 84. What are four hormones that the Duodenum secretes and what are their functions? Absorption of minerals Receives pancreatic digestive enzymes Secretes hormones Secretes enzymes Secretin Tells pancreas to secrete bicarbonate Tells liver to make bile Cholecystokinin (CCK) Tells pancreas to release protein-digesting enzymes Tells the gallbladder to release stored bile Therefore, it stimulates digestion of fat and protein GIP stimulates insulin secretion 85. What are the three enzymes secreted by the duodenum, and their functions? Motilin Initiates peristalsis (increases GI motility) Tells the Chief cells to secrete pepsinogen Maltase (breaks down maltose into glucose) Lactase (breaks down lactose into galactose and glucose 86. What is produced when amylase breaks down starch? 87. What breaks down maltose? 88. What does it break down into? 89. Where is maltose found in nature? Sucrase (breaks sucrose down into fructose and glucose) Maltose Maltase Two glucose molecules -Barley, caramelized glucose, malted milk shakes, malt liquor and beer 7 90. What sugar is needed for milk production? 91. How is lactose made? Lactose 92. What enzyme breaks down lactose? Lactase 93. What ethnic groups often lack lactase? Asians and Hispanic 94. What symptoms are produced in a lactose intolerant person who consumes dairy products? 95. What is an example of sucrose? 96. What is an example of Fructose? 97. Polysaccharide sugars and starches are broken down into what? Diarrhea and gas 98. Where are K cells found? In the duodenum and jejunum 99. What do K cells secrete? Glucose-dependent insulinotropic peptide (GIP) 100. What does GIP do? Stimulates insulin and lipase secretion from the pancreas 101. When do K cells secrete GIP? When there is no more chime entering the duodenum 102. What does insulin do with glucose in the blood? 103. What does lipase do? It pulls them into cells that need it. 104. What does bile do? Is it an enzyme? It emulsifies fat (breaks large drops into small droplets). It is a soap, not an enzyme. 105. What type of complex is formed from bile salts? Micelles Glucose + galactose Table sugar Fruit Glucose Breaks fat down into fatty acids and monoglycerides 8 106. What are micelles? small spherical globules of fat surrounded by bile salts 107. How do fatty acids and monoglycerides enter intestinal cells? 108. What is used to transport the monoglycerides into the intestinal cells? What happens after this substance drops off the monoglycerides? 109. What happens to the monoglycerides when it enters the intestinal cell? By diffusion. 110. After chylomicrons are produced, where are they transported to? They are transported to a lacteal (lymph capillary) within the villus of the small intestine. 111. Once in the lacteal, where is the chylomicron’s next location? They will travel in the lymph until they reach the thoracic lymph duct, which dumps into the subclavian artery 112. What is absorbed in the jejunum? Water-soluble vitamins, protein and carbohydrates. 113. Where in the body do proteins begin to break down? Proteins began to be break down into amino acids in the stomach by pepsin and acid. 114. In what part of the digestive tract are proteins broken down into amino acids? What enzymes do this? 115. Where is trypsin and chymotrypsin made and secreted from? They are broken down in the duodenum. Protein enzymes are trypsin and chymotrypsin Made by the pancreas and secreted into the duodenum. 116. Carbohydrates, nucleic acids, and proteins are broken down by enzymes that are made where? They are broken down in the duodenum by enzymes mainly from the pancreas and small intestine. Bile salts. They are reused. It is combined with proteins to form a chylomicron 9 117. Lipids are broken down by enzymes that are made where? 118. What 4 things does the ileum absorb? The liver 119. In what part of the digestive tract are fats broken down? What are they broken down into? 120. How are fats broken down? Fats are broken down into fatty acids in the duodenum 121. Which 2 hormones regulate the secretion of pancreatic juice? 122. Where are secretin and cholecystokinin produced? 123. What stimulates the secretion of secretin and cholecystokinin? secretin and cholecystokinin 124. What enzymes does the pancreas produce to break down fats, starches, and proteins? Lipases (fats) 125. What are the functions of Lipases? Fat-soluble vitamins, fat, cholesterol and bile salts First, bile emulsifies the fat (breaks it down into droplets) Then lipase breaks the fat into fatty acids produced by walls of the duodenum The presence of acidic food, proteins and fats in the duodenum Amylases (starches) Proteases (proteins) Digestion of fats, oils, and fat-soluble vitamins. 126. What are the functions of Amylases? Breaks down starch molecules into smaller sugars and breaks down carbohydrates into maltose, and then into glucose. 127. What are the 2 functions of Proteases? Breaks down protein into amino acids and keeps the small intestine free from parasites (worms, yeast, bacteria). 128. Name three Protease enzymes Trypsin, Chromotrypsin, and Carboxypeptidase. 10 129. What happens when someone lacks Proteases? Incomplete digestion that can lead to allergies and the formation of toxins. 130. When are Secretin and Cholecystokinin (CCK) secreted from the duodenum into the bloodstream? When fatty or acidic chyme enters the duodenum. 131. Once Secretin and CCK enter the bloodstream, where do they go? To the pancreas. 132. Upon reaching the pancreas, what does… a. Secretin do? a. causes secretion of bicarbonate to neutralize stomach acids. b. CCK do? b. induces the secretion of digestive enzymes that can digest lipids, proteins, and carbohydrates. 133. Which nerve also stimulates the secretion of pancreatic juices? Vagus nerve (CN X). 134. 98% of the function of the pancreas is what? Exocrine function; secretes digestive enzymes 135. What cells in the pancreas secrete the digestive enzymes? Acinar cells 136. 2% of the function of the pancreas is what? Endocrine function; secretes insulin, glucagon, digestive enzymes, somatostatin 137. What cells in the pancreas secrete somatostatin? -cells (delta cells) 138. What cells in the pancreas secrete insulin? β-cells (beta cells) 139. What cells in the pancreas secrete glucagon? α-cells (alpha cells) 11 140. What is the main function of insulin? Lowers blood sugar 141. What is the function of glucagon? Raises blood sugar 142. What is the function of gastrin? Increases HCl secretion in the stomach 143. What is the function of somatostatin? inhibitory to gastrin, insulin, and glucagon (inhibits the digestive system) 144. What three processes are inhibited by insulin? Fat breakdown (lipolysis) Glycogen breakdown (glycogenolysis) Formation of new glucose (gluconeogenesis) 145. How are proteins and fats influenced by insulin? Insulin promotes fat storage and protein synthesis 146. What effect does epinephrine have on insulin, and why? It inhibits insulin so blood sugars can remain high during stress, and fat can be broken down to make more glucose if needed. - Water and electrolytes 147. What are the two main things that are absorbed by the large intestine? 148. What allows for fermentation/break down of substances that remain after processing in the small intestine? - Gut bacteria 149. What is the main substance broken down by intestinal bacteria? Why is this important? - Complex polysaccharides. This is important because we can only digest three disaccharides at the most 150. What substance cannot go through the villi? - Cellulose (dietary fiber) 151. What happens to the food products that cannot go through the villi? - They are mixed with other waste products from the body, become hard and concentrated feces. 152. Why are coliform bacteria necessary? - They make vitamins that we need: - Vitamin K, biotin, and B5 12 153. Examples of organic wastes that are left in the lumen are…? - Urobilinogens and sterobilinogens 154. What is defecation reflex? - Mass movements of material through colon and rectum 155. What triggers the movement? - Mass movement is triggered by distention of the rectal walls. 156. What are coliforms? Bacteria that normally inhabit the large intestine. 157. Give example of one species of coliform? E. coli. 158. What is GALT? Gut-associated lymphoid tissue which keep harmful microorganism within the intestine at a minimum level 159. What are the three phases of gastric secretion? 160. When does the cephalic phase of gastric secretion occur? What is the purpose of the cephalic phase? - Cephalic phase - Gastric phase - Intestinal phase - Occurs before food enters the stomach. It prepares the body for ingestion and digestion. 161. What initiates the cephalic phase of gastric secretion? - Sight and thought of food, taste and smell of food. 162. What part of the brain is stimulated by the sight and thought of food? - Cerebral cortex 163. What part of the brain is stimulated by the taste and smell of food? - Hypothalamus and medulla oblongata 164. What happens after the brain is stimulated by sight, thought, taste, and smell of food? - The Vagus nerve (CN X) is stimulated, and it releases acetylcholine (Ach). 13 165. What happens to the acidity of the stomach during the cephalic phase of gastric secretion? - Since the acidity is not reduced by food yet, the high acid levels cause the D cells to secrete somatostation. 166. What effect does somatostatin have when the stomach has excess acidity? - Somatostatin tells the G cells to stop secreting gastrin. 167. What happens when the G cells stop secreting gastrin? - The parietal cells stop secreting HCl. 168. Where are G cells found? In the stomach 169. What neurotransmitter does the vagus nerve release when food arrives in the stomach? Gastrin-releasing peptide 170. What does gastrin-releasing peptide do? Activates G cells 171. What else activates G cells? The presence of proteins in the stomach 172. What do G cells secrete? G cells secrete the hormone, gastrin 173. What effect does gastrin have? Gastrin makes the parietal cells secrete HCl and the chief cells to secrete pepsinogen 174. What turns off gastrin secretion? When there is enough acid in the stomach 175. What three things stimulate the release of gastrin? Stomach distension, Vagus nerve stimulation, and the presence of proteins in the stomach. 176. What two things inhibit the release of gastrin? Enough HCl in the stomach, and somatostatin (growth hormone- inhibiting hormone) 14 177. Where are D cells located? In the stomach, intestine, and Islets of Langerhans in the pancreas 178. What is the function of D cells? They either increase or decrease somatostatin output 179. What causes the D cells to increase somatostatin output? Gastrin (from G-cells in the stomach) 180. What causes the D cells to decrease somatostatin output? Stimulation from the neurotransmitter, Ach 181. What is another name for Somatostatin? Growth hormone-inhibiting hormone. 182. What 4 gastrointestinal hormones does it suppress? Gastrin Chylecystokinin (CCK) Secretin GIP 183. Does it suppress or increase the release of pancreatic hormones? Suppress 184. What hormones does it inhibit in the pancreas? Insulin and Glucagon 185. Does somatostatin slow down or speed up the digestive process? Slow down 186. How is the gastric phase stimulated? By distension of the stomach, presence of food in stomach and decrease in pH. 187. How long does the gastric phase last? 3-4 Hours 188. What two reflexes are stimulated by gastric distention? The long reflex and the myenteric reflexes. 189. What do the long and myenteric reflexes activate? The release of acetylcholine which stimulates the release of more gastric juices. 15 190. As proteins enter the stomach, what do they bind to? What effect does this have on pH in the stomach? Hydrogen Ions, which raises the pH of the stomach. 191. As the pH in the stomach rises, what starts secreting? G cells in the stomach secrete the hormone gastrin, which stimulates parietal cells to secrete gastric acid (HCl). 192. What other substances trigger the release of gastric acid? Acetylcholine and histamine. 193. The intestinal phase of gastric section has what 2 opposing actions? EXCITATORY and INHIBITORY. 194. When partially digested foods fill the duodenum, what hormone is released by the stomach? GASTRIN 195. What reflex inhibits the Vagus nerve? ENTEROYGASTRIC REFLEX 196. What is the direct effect of the Enterogastric reflex? makes the pyloric sphincter tighten 197. When the pyloric sphincter tightens, what effect does it have? prevents more food from entering the duodenum 198. In what two ways are peptic ulcers classified? By region and by type 199. What are three types of peptic ulcers as classified by region? Duodenal, esophageal, and gastric ulcers. 200. Duodenal ulcers and gastric ulcers in the body of the stomach are what type classification? TYPE 2 201. Which ulcer type is In the pyloric region? TYPE 3 16 202. Which ulcer type is associated with chronic aspirin use? Type 5 203. What type of diabetes is called “adult onset”? At what age does it occur Type II usually occurs after age 40 204. What is the problem in people with Type II diabetes? All the cells in the body have a lowered sensitivity to insulin; the insulin receptors on the cell membranes are not working properly, and the glucose is not transported into the cell. 205. What causes Type II diabetes? Obesity. A person who has extra energy stored in their body will stop producing insulin receptors on their cell membranes because their cells do not need glucose. 206. How is Type 2 diabetes controlled? Dietary changes and regular exercise 207. What are two pancreatic disorders? Pancreatitis and pancreatic cancer 208. How is absorption of fat, proteins, and carbohydrates affected without pancreatic enzymes? 60% fat not absorbed, causing steatorrhea (fatty stools) 30-40% protein and carbohydrates not absorbed 17 Organ Pancreas Region of the Organ Acinar cells Acinar cells Substances Amylase (enzyme) Lipase (enzyme) Function Breaks down starch and carbohydrates into glucose Breaks down fat into fatty acids Acinar cells Acinar cells Protease enzymes (trypsin, chymotrypsin, carboxypeptidase) Bicarbonate (not an enzyme) Breaks down proteins into amino acids and also kills intestinal parasites and bacteria Raises pH in duodenum Islet of Langerhans; Alpha cells glucagon (hormone) Causes glycogenolysis, the process which breaks down glycogen into glucose to raise blood glucose. Also causes gluconeogenesis to make new glucose molecules Islet of Langerhans; Beta cells insulin (hormone) Removes glucose in bloodstream and brings it into cells. Lowers blood glucose levels. Islet of Langerhans; Delta cells Somatostatin (hormone) Inhibits gastrin, insulin, and glucagon (inhibits digestive system) Liver Bile (a detergent) Salivary glands Amylase (enzyme) Stomach Mucous (not an enzyme) Protect the stomach lining Prostaglandins (not an enzyme) Protect the stomach lining Breaks down starch and carbohydrates into glucose HCl (not an enzyme) Allows Pepsinogen to be converted to pepsin, and it also kills bacteria Parietal cells Intrinsic factor (not an enzyme) Allows Vit B12 to be absorbed, which is needed to make RBCs. Without it, you get megaloblastic (pernicous) anemia. Chief cells G cells Pepsinogen --> pepsin (enzyme) Gastrin (hormone) Breaks proteins into amino acids Tells parietal cells to secrete HCl Parietal cells 18 Organ Duodenum Region of the Organ K cells Substances Secretin (hormone) Function Tells pancreas to secrete bicarbonate CCK (hormone) Tells pancrease to secrete proteases, and tells gallbladder to release stored bile (stimulates fat and protein digestion) GIP (hormone) Tells pancreas to release insulin and also causes fat to be broken down into fatty acids Motilin (hormone) Initiates perstalsis and tells Chief cells to secrete pepsinogen Maltase, Lactase, Sucrase (enzymes) Break down complex carbohydrates into glucose 19