GIT Physio Flashcards
Sectioning of vagal nerve supply to stomach will cause all of the following EXCEPT:
A. Decreased gastric mucus secretion
B. Decreased gastric acid secretion
C. Decreased gastric emptying
D. Decreased distension of the stomach
E. Decreased mucosal growth
C. a plain vagotomy is not very realistic in modern times and it is more likely to be a case of highly selective vagotomy. This refers to denervation of only those branches supplying the lower esophagus and stomach (leaving the nerve supply of the antrum and pylorus in place to ensure the emptying function of the stomach remains intact). It is one of the treatments of peptic ulcer.
Drinking 500ml of water ONLY will lead to the following:
A. Absorption via paracellular route in small intestines only
B. Absorption in large intestine
C. Absorption dependent on sodium and glucose
D. Release of ADH from hypothalamus
E. Decreased intestinal transit
C. Water movement follows solutes, hence that is why oral rehydration therapy using glucose saved 50 million lives. Making patients drink lots of water alone does not really help with water absorption.
A lipase inhibitor can cause the following symptoms except:
A. Weight loss
B. Diarrhea
C. Vitamin D deficiency
D. Loss of bile salts
E. Foul smelling stools
D. Lipase inhibitors reduce the gastrointestinal absorption of fat by preventing fat digestion. Hence, this can cause weight loss (option A), diarrhoea (option B), steatorrhea (option E, bacterial fermentation of fat), and vitamin D deficiency (option C) because fat soluble vitamins (A,D,E,K) are absorbed together with fat. The mechanism by which lipase inhibitors can cause diarrhea is primarily related to the presence of unabsorbed fats in the gastrointestinal tract. When dietary fats are not broken down and absorbed properly due to lipase inhibition, they remain undigested in the intestines and can exert osmotic effects.
Complete obstruction of the common bile duct leads to all of the following EXCEPT:
A. Jaundice
B. Raised conjugated bilirubinaemia
C. Pale stools
D. Bilirubin in the urine
E. Urobilirubin the urine
E. We do not use the term urobilirubin (option E). Options A-D are classic symptoms of post-hepatic jaundice.
Total gastrectomy can result in all the following EXCEPT:
A. Bacterial overgrowth
B. Loss of weight
C. Vitamin B12 deficiency
D. Diarrhea
E. Carbohydrate malabsorption
E. Gastrectomy results in loss of gastric acids which have bacteriostatic effect (causing bacterial overgrowth, option A), reduced production of intrinsic factor (causing B12 deficiency, option C). Diarrhoea (option D) may result because the food passes too quickly through the colon, as there is no pyloric sphincter to regulate gastric emptying, causing gastric dumping syndrome. Without a stomach, this limits the amount of food we can eat by making us feel full after eating small amounts of food, causing weight loss (option B); vertical sleeve gastrectomy is a method to help obese patients lose weight. Option E is the answer because carbohydrate digestion and absorption occurs mostly in the small intestines.
With reference to gastric function,
a. The average meal has moved from the stomach after ½ hour
b. Contractility is augmented by sympathetic stimulation
c. When the quantity of ingested material increases, the intragastric pressure increases
d. The longitudinal muscle coat has a basic electrical rhythm
e. Histamine inhibits the production of gastric acid
D. 12. Option A is wrong because 2-3h is required for stomach to empty an average meal. Option B is wrong because contractility or gastric churning is stimulated by parasympathetics. Option C is wrong because receptive and adaptive relaxation of stomach occurs to accommodate entry of food, minimizing any rise in intragastric pressure. Option E is wrong because histamine, secreted by ECL cells, stimulates HCl secretion by parietal cells.
Option D is correct as the interstitial cells of Cajal are specialized pacemaker cells located in the wall of the stomach, small intestine, and large intestine. The cell membranes of the pacemaker cells undergo a rhythmic depolarization and repolarization, creating a slow wave known as a Basic Electrical Rhythm, and it is transmitted to the smooth muscle cells. The frequency of these depolarizations in a region of the GI tract determines the possible frequency of contractions.
Which following hormone stimulates pancreatic HCO3- secretion in the presence of decreased secretion?
a. gastrin
b. VIP
c. GIP
d. CCK
e. Somatostatin
B. Vasoactive Intestinal Peptide (VIP, Option B) is a neuropeptide; its role in the intestine is to greatly stimulate secretion of water and electrolytes, stimulate pancreatic bicarbonate secretion, and inhibiting gastrin-stimulated gastric acid secretion.
Which of the following is true:
a. 95% of bile pigments secreted by the liver is absorbed in the gut
b. most of the water absorbed in GIT is derived from dietary intake
c. CCK neutralizes the small intestine of acid from the stomach
d. Cl- is secreted into the bile in the gall bladder
e. malabsorption of lipids will lead to failure of pancreatic secretion
A. Option A (refer to q14,15) Enterohepatic circulation occurs for both bile acids and bile pigments. Bile pigments refer to colored compounds from the breakdown of haem - bilirubin, urobilin, stercobilin etc. Option B is wrong because most of the absorbed fluids are secretions (e.g. bile, pancreatic juice, saliva, gastric juice).
. Parasympathetic blockade of the GIT leads to which of the following
A. abdominal pain
B. increase intestinal transit time
C. increase bile secretions
D. increase fecal water loss
E. increase mucous secretion
B. Parasympathetics regulate intestinal motility in various ways. For example, ileal peristalsis intensifies after a meal, emptying ileal contents into the cecum so as to make way for the new meal (gastroileal reflex). Hence, parasympathetic blockade will increase the time taken for food to travel through the intestines (option B).
In pernicious anaemia, an autoimmune process destroys the “proton pump” and the parietal cells. Which one of the following observations is TRUE:
a. Acid secretion is normal
b. Absorption of intrinsic factor is affected
c. Blood gastrin level is raised
d. Blood histamine level is raised
e. Blood H+ is raised
C. Acid usually inhibits gastrin relase. With less acid, more gastrin is produced
In the regulation of pancreatic secretion:
a. Low duodenal pH stimulates alkaline secretion
b. Secretin stimulates enzyme secretion
c. CCK stimulates HCO3 secretion
d. Gastrin stimulates acid secretion
e. Enterokinase stimulates protease secretion
A. Acidic chime entering duodenum triggers secretin release by S cells. Secretin stimulates ductal cells of pancreas to secrete isosmotic HCO3- and water to neutralize stomach acid.
Entry of acidic chyme into the duodenum causes all the following except
a. Release of secretin
b. Contraction of sphincter of oddi
c. Contraction of gall bladder
d. Increased pancreatic secretion
e. Inhibition of gastric emptying
B. Acidic chyme entering duodenum triggers secretin release (option A) by S cells. This increases pancreatic secretion of alkaline pancreatic juice (option D), and also slows gastric emptying (option E) via duodenogastric reflex. The hormone cholecystokinin (CCK) stimulates contractions in the smooth muscle of the gallbladder (option C), and also causes relaxation of the sphincter of Oddi, allowing bile release into the duodenum. Hence option B is the answer
The following are true of bile salts except:
a) Synthesized from cholesterol
b) Converted by intestinal bacteria to secondary bile salts
c) Acts as “detergent” in gut
d) Vast majority absorbed in proximal small intestine
e) Causes itch in skin during obstructive jaundice
Option D is wrong as most bile salts are reabsorbed in the terminal ileum.
Which of the following induces contraction of gallbladder smooth muscle?
a. Secretin.
b. Cholecystokinin
c. Serotonin
d. Gastrin
e. Somatostatin
B. CCK stimulates contraction of gall bladder smooth muscle (option B) to increase secretion of bile into duodenum, in response to more fat and protein entering the duodenum.
High doses of antibiotics can destroy the bacterial flora of the large intestine. This can result in impaired:
a. Absorption of protein
b. Blood coagulation
c. Bone resorption
d. Respiratory control
B. . Bacterial flora in large intestines produce vitamin K, which is needed to produce clotting factors (option B).
Absorption of protein (option A) occurs in small intestines via Na+ dependent cotransporters.
A doctor suspects a patient of having familial LPL deficiency. Elevation of which of the following particles will confirm his diagnosis?
a. LDL
b. Chylomicron Remnants and IDL
c. HDL
d. VLDL
e. Chylomicrons
E. Lipoprotein lipase (LPL) is a key enzyme required for the hydrolysis of TGs in chylomicrons. Chylomicrons is “highest” in the chain of structures
