Digestive system Physiology-Critical thinking
1. While anesthetized, patients sometimes vomit. Given that the anesthetic eliminates the swallowing reflex, explain why it is dangerous for an anesthetized patient to vomit.
2. Achlorhydria is a condition in which the stomach stops producing hydrochloric acid and other secretions. What effect would achlorhydria have on the digestive process? On red blood cell count?
3. Victor Worrystudent experienced the pain of a duodenal ulcer during final examination week. Explain what habits caused the ulcer, and recommend possible remedies.
4. Gallstones sometimes obstruct the common bile duct. What are the consequences of such a blockage?
5. A patient has a spinal cord injury at level L2. How does this injury affect the patient’s ability to defecate? What components of the defecation response are still present, and which are lost?
6. The bacterium Vibrio cholerae produces cholera toxin, which activates a chloride channel in the intestinal epithelium. In contrast, mutations that inactivate the same channel cause cystic fibrosis. Explain how increased chloride channel activity causes severe diarrhea, whereas decreased activity causes the intestinal symptoms of cystic fibrosis.
7. Discuss why the most effective oral rehydration therapy is water containing sodium and glucose instead of water alone or water with fructose.
8. Would a patient with familial hypercholesterolemia (FH) benefit from dietary changes?
9. Why would you not want to completely suppress HCl secretion in the stomach?
10. Trey has cystic fibrosis, a genetic disorder that is characterized by the production of excessive mucus, affecting several body systems (e.g., respiratory, digestive, reproductive). In the digestive system, the excess mucus blocks bile ducts in the liver and pancreatic ducts. How would this affect Trey’s digestive processes?
but he needed to watch his diet. What happened to Antonio?
11. Antonio had dinner at his favorite Italian restaurant. His menu consisted of a salad, a large plate of spaghetti, garlic bread, and wine. For dessert, he consumed “death by chocolate” cake and a cup of coffee. He topped off his evening with a cigarette and brandy. He returned home and, while lying on his couch watching television, he experienced a pain in his chest. He called 911 because he was certain he was having a heart attack. Antonio was told his heart was fine,
12. Some people with gallstones develop pancreatitis. How could this occur?
13. Harry is suffering from an obstruction in his colon. He notices that when he urinates, the color of his urine is much darker than normal, and he wonders if there is any relationship between the color of his urine and his intestinal obstruction. What would you tell him?
14. A condition known as lactose intolerance is characterized by painful abdominal cramping, gas, and diarrhea. The cause of the problem is an inability to digest the milk sugar lactose. How would this cause the observed signs and symptoms?
15. Recently, more people have turned to surgery to help them lose weight. One form of weight control surgery involves stapling a portion of the stomach shut, creating a smaller volume. How would such a surgery result in weight loss?
16. Why do patients who have had a large part of their stomachs removed for treatment of stomach cancer or severe peptic ulcer disease have to eat small quantities of food frequently instead of consuming three meals a day?
17. The number of immune cells in the gut-associated lymphoid tissue (GALT) housed in the mucosa is estimated to be equal to the total number of these defense cells in the rest of the body. Speculate on the adaptive significance of this extensive defense capability of the digestive system.
18. How would defecation be accomplished in a patient paralyzed from the waist down by a lower spinal-cord injury?
19. After bilirubin is extracted from the blood by the liver, it is conjugated (combined) with glucuronic acid by the enzyme glucuronyl transferase within the liver. Only when conjugated can bilirubin be actively excreted into the bile. For the first few days of life, the liver does not make adequate quantities of glucuronyl transferase. Explain how this transient enzyme deficiency leads to the common condition of jaundice in newborns.
20. Explain why removal of either the stomach or the terminal ileum leads to pernicious anemia.
21. Bariatric surgery is a type of medical procedure that reduces the size of the stomach and enables food to bypass a section of the small intestine. The surgery is generally done when obese individuals have unsuccessfully tried numerous ways to lose weight and their health is compromised by their weight. There are many risks associated with the surgery, but it helps a number of people lose a considerable amount of weight and ultimately improve their overall health. After people undergo the surgery, there are several lifestyle changes they must make to avoid nutritional deficiencies and to compensate for the small size of their stomach.
1. a. Why do some people who have had bariatric surgery process their food in a blender (or have to chew thoroughly) before swallowing their food? b. Why should people who have had bariatric surgery drink liquids between meals rather than with meals?
2. What risk is there to the esophagus after bariatric surgery?
22. Some people with gallstones develop pancreatitis. How could this occur?
23. Harry is suffering from an obstruction in his colon. He notices that when he urinates, the color of his urine is much darker than normal, and he wonders if there is any relationship between the color of his urine and his intestinal obstruction. What would you tell him?
24. A condition known as lactose intolerance is characterized by painful abdominal cramping, gas, and diarrhea. The cause of the problem is an inability to digest the milk sugar lactose. How would this cause the observed signs and symptoms?
25. Recently, more people have turned to surgery to help them lose weight. One form of weight control surgery involves stapling a portion of the stomach shut, creating a smaller volume. How would such a surgery result in weight loss?
26. If the salivary glands were unable to secrete amylase, what effect would this have on starch digestion?
27. Whole milk or a fatty snack consumed before the ingestion of alcohol decreases the rate of intoxication. By what mechanism may fat be acting to produce this effect?
28. A patient brought to a hospital after a period of prolonged vomiting has an elevated heart rate, decreased blood pressure, and below-normal blood K+ and acidity. Explain these symptoms in terms of the consequences of excessive vomiting.
29. Can fat be digested and absorbed in the absence of bile salts? Explain.
30. How might damage to the lower portion of the spinal cord affect defecation?
31. Vibrio Cholerae causes diarrhea How?
32. One of the older but no longer used procedures in the treatment of ulcers is abdominal vagotomy, surgical cutting of the vagus (parasympathetic) nerves to the stomach. By what mechanism might this procedure help ulcers to heal and decrease the incidence of new ulcers?
33. Your aerobics instructor tells you that exercise helps to prevent constipation. Is the instructor correct? Can you think of any plausible explanation?
34. What is the function of bicarbonate in the pancreatic juice? Explain why stress ulcers are more likely to be located in the duodenum than in the stomach.
35. A 42-year-old male presents to your clinic with abdominal pain secondary to mild idiopathic chronic pancreatitis. you decide to manage the patient with pancreatic enzyme supplementation. Which of the following is the most likely mechanism for pancreatic enzyme replacementmediated improvement of abdominal pain associated with chronic pancreatitis?A. Neutralization of duodenal secretion
B. breakdown of CCK-releasing peptide
C. breakdown of secretin-releasing peptide
D. induction of CCK-releasing peptide
E. induction of secretin-releasing peptide
36. Why is infection relatively uncommon after oral surgery in spite of the fact that antiseptic measures are inconvenient to employ?
37. Why are children often told to spit on their wounds?
38. Why is atropine premedication given before anaesthesia?
39. While one is waiting for an oral examination, the mouth often gets dry. On the other hand, sometimes in a state of extreme fear or anger, one feels the need to swallow saliva repeatedly. How can you explain these opposite responses to stress?