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3# Pancreatic, liver & biliary secretion
Q1. The approximate daily volume of pancreatic secretion in adults is:
0.5 L
1.5 L
3 L
5 L
Explanation:
The pancreas secretes about 1.5 liters of pancreatic juice per day composed of enzyme-rich acinar secretions and bicarbonate-rich ductal secretions.
Q2. Which pancreatic cells primarily secrete digestive enzymes?
Duct cells
Islet cells
Acinar cells
Kupffer cells
Explanation:
Acinar cells produce enzyme-rich pancreatic secretions, while duct cells secrete bicarbonate-rich watery fluid.
Q3. The bicarbonate-rich component of pancreatic secretion is produced mainly by:
Duct epithelial cells
Acinar cells
Pancreatic islets
Hepatocytes
Explanation:
Epithelial cells lining pancreatic ducts secrete bicarbonate-rich fluid that neutralizes acidic chyme entering the duodenum.
Q4. The primary physiological role of bicarbonate in pancreatic secretion is to:
Activate pepsin
Stimulate bile production
Enhance carbohydrate digestion
Neutralize acidic chyme
Explanation:
Bicarbonate neutralizes gastric acid entering the duodenum to create an alkaline environment for pancreatic enzyme activity.
Q5. Which pancreatic proteolytic enzyme is secreted in inactive form?
Lipase
Amylase
Trypsinogen
Ribonuclease
Explanation:
Trypsinogen is secreted as an inactive zymogen to prevent autodigestion of pancreatic tissue.
Q6. Which enzyme activates trypsinogen in the duodenum?
Pepsin
Enterokinase
Lipase
Carboxypeptidase
Explanation:
Enterokinase (enteropeptidase) located in the brush border of the duodenum converts trypsinogen into trypsin.
Q7. Trypsin activates other pancreatic enzymes mainly through:
Phosphorylation
Oxidation
Inhibition
Autocatalytic activation
Explanation:
Once activated, trypsin activates other pancreatic zymogens including chymotrypsinogen and procarboxypeptidase.
Q8. Pancreatic lipase mainly converts triglycerides into:
Fatty acids and monoglycerides
Cholesterol and glycerol
Diglycerides only
Fatty acids only
Explanation:
Lipase hydrolyzes triglycerides into monoglycerides and free fatty acids.
Q9. Which hormone is the primary stimulant of pancreatic bicarbonate secretion?
Gastrin
Secretin
CCK
Motilin
Explanation:
Secretin stimulates duct cells of pancreas to secrete bicarbonate-rich fluid.
Q10. Cholecystokinin (CCK) primarily stimulates:
Bicarbonate secretion
Water secretion
Pancreatic enzyme secretion
Insulin secretion
Explanation:
CCK released from I-cells stimulates secretion of enzyme-rich pancreatic juice.
Q11. Secretin release is primarily stimulated by:
Fat in duodenum
Protein digestion products
Glucose
Acidic chyme
Explanation:
Acid entering the duodenum stimulates S cells to release secretin.
Q12. Approximately what percentage of pancreatic secretion occurs during the cephalic phase?
5%
20%
50%
70%
Explanation:
About 20% of pancreatic secretion occurs during the cephalic phase through vagal stimulation.
Q13. The gastric phase contributes approximately how much pancreatic secretion?
1–3%
2–4%
5–10%
40–50%
Explanation:
The gastric phase contributes about 5–10% of pancreatic secretion through vagal stimulation.
Q14. The intestinal phase of pancreatic secretion is stimulated mainly by:
Secretin and CCK
Gastrin and histamine
VIP and motilin
Somatostatin and insulin
Explanation:
In the intestinal phase, secretin stimulates bicarbonate secretion while CCK stimulates enzyme secretion.
Q15. Bile production in adults is approximately:
0.1 L/day
0.3 L/day
2–3 L/day
0.6–1 L/day
Explanation:
Hepatocytes produce approximately 0.6–1 liter of bile per day.
Q16. The golden yellow color of bile is due to:
Cholesterol
Bilirubin
Bile salts
Phospholipids
Explanation:
Bilirubin is the pigment responsible for the characteristic yellow color of bile.
Q17. The most potent stimulus for gallbladder contraction is:
Secretin
Gastrin
CCK
Motilin
Explanation:
Cholecystokinin strongly stimulates gallbladder contraction.
Q18. Approximately what percentage of bile salts are reabsorbed in the terminal ileum?
50%
60%
80%
95%
Explanation:
About 95% of bile salts are reabsorbed in the terminal ileum and recycled through enterohepatic circulation.
Q19. Bile acids are synthesized from which precursor?
Triglycerides
Cholesterol
Phospholipids
Fatty acids
Explanation:
Hepatocytes synthesize bile acids from cholesterol.
Q20. Bile acids are conjugated mainly with:
Alanine
Aspartate
Glycine
Glutamate
Explanation:
Bile acids conjugate mainly with glycine (and some taurine) in the liver.
Q21. Bile salts are formed when conjugated bile acids combine with:
Na+ or K+
Ca2+
Cl-
Mg2+
Explanation:
Conjugated bile acids combine with sodium or potassium to form bile salts.
Q22. The primary digestive function of bile salts is:
Protein digestion
Carbohydrate digestion
Vitamin B12 absorption
Fat absorption
Explanation:
Bile salts form micelles that facilitate absorption of lipids and fat-soluble vitamins.
Q23. Enterohepatic circulation refers to:
Movement of bile from liver to intestine
Recycling of bile salts between intestine and liver
Secretion of bile into gallbladder
Storage of bile in gallbladder
Explanation:
Bile salts are reabsorbed in the ileum and transported back to the liver for resecretion.
Q24. Which bile acid derivative cannot be reabsorbed effectively?
Cholic acid
Deoxycholic acid
Lithocholic acid
Chenodeoxycholic acid
Explanation:
Lithocholic acid is poorly absorbed and is mainly excreted in feces.
Q25. Terminal ileum resection may cause:
Fat malabsorption
Protein malabsorption
Carbohydrate malabsorption
Iron deficiency
Explanation:
Loss of bile salt reabsorption leads to reduced micelle formation and fat malabsorption (steatorrhea).
Q26. Gallbladder bile may be concentrated up to:
2–3 fold
3–5 fold
5–10 fold
5–20 fold
Explanation:
Bile is concentrated in the gallbladder up to 5–20 times due to water and electrolyte absorption.
Q27. Bile secretion is stimulated by all of the following EXCEPT:
Vagus nerve
Somatostatin
Secretin
Bile salts
Explanation:
Bile secretion is stimulated by vagal activity, secretin, and bile salts themselves.
Q28. If pancreatic duct obstruction occurs, the most likely consequence is:
Gallstones
Hyperglycemia
Acute pancreatitis
Cirrhosis
Explanation:
Blocked ducts may allow trypsin activation inside pancreas causing autodigestion and acute pancreatitis.
Q29. Pancreatic amylase digests:
Starch and glycogen
Cellulose
Triglycerides
Collagen
Explanation:
Pancreatic amylase acts on starch and glycogen but cannot digest cellulose.
Q30. Which pancreatic enzyme facilitates lipase action?
Amylase
Elastase
Trypsin
Colipase
Explanation:
Colipase binds lipase to fat droplets and enhances its enzymatic activity.