Monday, November 5, 2007

Gastro intestinal system.(MCQ)

TRUE/FALSE (Qs 1-10)

1. All the muscles in the GIT are smooth muscle.
2. After death the length of the intestine is shorter than in vivo.
3. The small intestine can respond to stretch by an increase or a decrease in tension.
4. The entire lining of the small intestine is replaced in 5-6 days.
5. The sympathetic supply of the GIT relaxes the muscularis mucosa.
6. The sympathetic supply blocks the release of mediators from parasympathetic terminals from the myenteric plexus.
7. Mechanoreceptors are found in mucosa, sub mucosa and muscle layers.
8. The oral stage is the only voluntary stage of swallowing.
9. Vagal innervation is essential for the orderly propagation of the primary peristaltic wave along the esophagus.
10. The vomiting center is situated in the hypothalamus.

1. F (Voluntary muscle is present in esophagus and rectum.)
2. F. 3. T. 4.T. 5. F. 6.T. 7.T. 8.T. 9.T. 10.F. (in the medulla ventral to nucleus of solitary tract.)

(Qs 11-20)
11. Receptive relaxation only occurs in the proximal stomach.
12. Gastric emptying can be either increased or decreased by osmoreceptors in the duodenal mucosa.
13. Segmental movements in the small intestine can occur in completely denervated gut.
14. Peristalsis in the small intestine can be initiated by a myoelectric complex in the antrum/duodenum.
15. Haustral movements are as likely to cause retrograde as orthrograde progression.
16. Aganglionosis of colon (Hirschprung’s disease) causes mega colon.
17. The desire to defecate is related to intrarectal pressure.
18. Normally the secretion of saliva is less than 600 ml/day.
19. Co2 escapes from saliva once it enters the mouth.
20. The parotid glands normally provide most of the salivary volume.

11. T. 12.T. 13.T. 14.T. 15.T. (Haustrations are due to annular constrictions of circular muscle.)
16. T. 17.T. (Occurs at 20 mmHg; it becomes intense at 50mmHg)
18. F. (1-1.5Litres/day)
19. T. (KHCO3=CO2+KOH) this allows the mouth PH to rise.)

20. F. (Submandibulars provide 70% of salivary volume)

(Qs 21-30)
21. H.pylori infection is nowadays widely accepted as the most common known cause of peptic ulcer.
22. Secretin provokes a very alkaline pancreatic secretion.
23. Only one third of liver bile comes from the hepatocytes.
24. Gall bladder bile is more acid than hepatic bile.
25. Water is reabsorbed by a primary active process from the gall bladder.
26. The normal cholesterol: bilesalts ratio should be less than 1:20
27. Gallstones are most likely to be formed at night or if meals are skipped.
28. G cells are exempt from neural control.
29. Gastrin is important in maintaining gastric mucosal growth.
30. Secretin inhibits gastrin mediated H+ secretion in the stomach.

21. T. 22. T. 23.T. 24.T. 25.F. 26.T. 27.T. 28.F. (non-cholinergic vagal fibers secrete gastrin releasing peptide)
29. T. 30.T.


31. CCK promotes the concentration of bile in the gall bladder.
32. Aminoacid absorption is virtually unimpaired in a secretory diarrhea.
33. Up to half of the ingested glucose is absorbed in the first 20cm of the jejunum.
34. Absorption only occurs after carbohydrates have been broken down to hexose sugars.
35. Lactose intolerance is due to a failure to absorb the lactose molecule.
36. A chylomicron consists of cholesterol and phospholipid covered in a layer of protein only.
37. Most chloride absorption in the jejunum is by paracellular route.
38. Diarrhea is usually due to problems originating in the large intestine.
39. Serotonin may cause diarrhea by increasing cytoplasmic calcium.
40. The lipostatic theory states that feeding is under the long-term control of total body adipose mass.

31. F. 32.F. 33.F. (normally all glucose absorption is completed in the proximal jejunum.)
34. F. (pentose sugars are readily absorbed)
35. F. (failure to digest lactose.)
36. F. (also contains triglycerides and often traces lipids)
37. T. 38.F. 39.T. (after over eating bananas-rich in 5-HT.)
40. T(leptin is a protein that regulates body weight and that is encoded in adipocytes).

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