GIT and CNS Physiology MCQs – 70 MCQs | Kenya MBChB

70 Year 2: GIT Physiology exam questions on GIT and CNS Physiology MCQs for medical students. Includes MCQs, answers, explanations and written questions. Sample

This MCQ set contains 70 questions on GIT and CNS Physiology MCQs in the Year 2: GIT Physiology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: Which single statement below, about the stomach, is correct?

  1. A. Acid secretion occurs in response to secretion of the hormone, carbonic anhydrase
  2. B. Glands called Peyer's patches are responsible for acid secretion
  3. C. The vagus nerve inhibits acid secretion after a meal has been consumed
  4. D. Pepsinogen and gastric lipase are secreted into the lumen of the stomach

Correct answer: A – Acid secretion occurs in response to secretion of the hormone, carbonic anhydrase

Q2: Water transport can occur from the lumen of the intestine to the bloodstream, or vice versa. Which statement is correct?

  1. A. A "flip-flop" mechanism efficiently transports water directly across the enterocyte membrane
  2. B. Water flows into the gut from the mucosa during digestion of starch and protein to reduce luminal osmolality
  3. C. Water is mostly absorbed by movement between enterocytes via tight junctions
  4. D. Dietary intake of water is always greater than water movement in the small intestine

Correct answer: A – A "flip-flop" mechanism efficiently transports water directly across the enterocyte membrane

Q3: Which statement about fat digestion and absorption is correct?

  1. A. Fatty acids are absorbed mainly via FABP and FAT/CD36 in the distal duodenum
  2. B. Medium-chain triglycerides (MCT) enter lymphatics; long-chain triglycerides enter portal blood
  3. C. Partial digestion products form mixed micelles with cholesterol/phospholipids, enhancing absorption
  4. D. Triglycerides must be emulsified and digested before fatty acids are transported

Correct answer: A – Fatty acids are absorbed mainly via FABP and FAT/CD36 in the distal duodenum

Q4: Which statement about protein digestion is most correct?

  1. A. Products of protein digestion are absorbed as free amino acids or di-/tripeptides
  2. B. Gastric digestion of all proteins is equally efficient due to antral grinding
  3. C. Chief cells secrete chymotrypsin, elastase, and carboxypeptidase A
  4. D. Only one of 14 amino acid transporters absorbs digested protein products

Correct answer: A – Products of protein digestion are absorbed as free amino acids or di-/tripeptides

Q5: Which statement about dietary fibre is most correct?

  1. A. Fermentation end products are mainly malic, succinic, and propionic acids
  2. B. Soluble/insoluble fibres are completely fermented within 24 hours in vitro
  3. C. Fiber sources such as Hemicelluloses, pectins, and inulin ferment rapidly to SCFAs with trophic colon effects
  4. D. Stool bulking occurs mainly via insoluble fibres like cellulose

Correct answer: A – Fermentation end products are mainly malic, succinic, and propionic acids

Q6: Which statement about absorption is most correct?

  1. A. Glucose absorption is associated with sodium uptake
  2. B. Fructose is absorbed more rapidly than glucose
  3. C. Galactose and fructose share the same brush-border transporter
  4. D. Most water absorption occurs in the colon

Correct answer: A – Glucose absorption is associated with sodium uptake

Q7: Which statement about the oral phase of digestion is INCORRECT?

  1. A. ~2% of food energy is expended in chewing/swallowing
  2. B. Swallowing involves 14 muscle groups over ~10 seconds in healthy subjects
  3. C. Tooth enamel biofilm contains salivary/bacterial enzymes
  4. D. Salivary amylase digests dextran film from dietary sucrose

Correct answer: A – ~2% of food energy is expended in chewing/swallowing

Q8: Which statement about stomach lining cells is correct?

  1. A. Mucous cells secrete the glycoprotein mucin
  2. B. Chief cells secrete the hormone gastrin
  3. C. Parietal cells secrete pepsinogen
  4. D. G Cells secrete hydrochloric acid

Correct answer: A – Mucous cells secrete the glycoprotein mucin

Q9: Which statement about pancreatic enzyme secretion is correct?

  1. A. Pepsinogen is the chief protein-digesting enzyme
  2. B. Pancreatic α-amylase hydrolyzes starch to free glucose
  3. C. Enteropeptidase converts trypsinogen to trypsin by cleaving an inhibitory peptide
  4. D. Pancreatic HCl secretion is required for duodenal enzyme pH

Correct answer: A – Pepsinogen is the chief protein-digesting enzyme

Q10: Which statement about post-meal motility is correct?

  1. A. Migrating motor complex drives peristalsis after a meal
  2. B. Insulin slows gastric emptying
  3. C. Stomach increases tone at meal start to expel contents via pylorus
  4. D. Partially digested fat/starch in the duodenum slows intestinal motility

Correct answer: A – Migrating motor complex drives peristalsis after a meal

Q11: Which best describes colonic microbiota functions?

  1. A. Daily fibre intake underestimates fermentable material in the colon
  2. B. All of the options given are correct
  3. C. Acetate, propionate, butyrate are main SCFAs from fermentation
  4. D. Acetate buffer suppresses pathogenic bacteria growth

Correct answer: A – Daily fibre intake underestimates fermentable material in the colon

Q12: What explains fibre's protective effect against colon cancer?

  1. A. Propionic acid inhibits liver fatty acid synthesis
  2. B. Butyric acid silences the SLC5A8 tumor suppressor gene
  3. C. None of these options are correct
  4. D. Butyric acid stimulates colon antioxidant defenses

Correct answer: A – Propionic acid inhibits liver fatty acid synthesis

Q13: Which best describes vitamin absorption?

  1. A. All of the options given are correct
  2. B. Vitamin E is absorbed by a peroxidized fatty acid-binding protein
  3. C. Thiamine pyrophosphate must be dephosphorylated for absorption
  4. D. Dehydroascorbic acid (oxidized vitamin
  5. E. uses a glucose transporter

Correct answer: A – All of the options given are correct

Q14: Which best describes the intestine's role in obesity?

  1. A. Obesity results from deranged gut hormones (e.g., low PYY)
  2. B. Gut/brain signaling controls energy intake within 2% even in morbid obesity
  3. C. Gluttony overrides strong satiety signals regularly
  4. D. Processed food flavors override satiety post-meal

Correct answer: A – Obesity results from deranged gut hormones (e.g., low PYY)

Q15: Which is true about pancreatic secretions vs. plasma?

  1. A. Higher secretion rate increases bicarbonate/sodium; plasma has less bicarbonate
  2. B. Higher secretion increases bicarbonate but decreases chloride
  3. C. Higher secretion increases osmolarity/pH; plasma is lower
  4. D. Higher secretion increases bicarbonate/potassium; plasma has lower levels

Correct answer: A – Higher secretion rate increases bicarbonate/sodium; plasma has less bicarbonate

Q16: Which has little effect on pancreatic secretion?

  1. A. Acetylcholine
  2. B. Sympathetic stimulation
  3. C. Secretin
  4. D. Cholecystokinin

Correct answer: A – Acetylcholine

Q17: Defective parietal cells cause malabsorption of which vitamin?

  1. A. Vitamin B1
  2. B. Vitamin B2
  3. C. Vitamin B13
  4. D. Vitamin B12

Correct answer: A – Vitamin B1

Q18: Which is absorbed by passive diffusion via concentration gradient?

  1. A. Sodium
  2. B. Potassium
  3. C. Calcium
  4. D. Phosphate

Correct answer: A – Sodium

Q19: How much of the ~9L daily GI tract water exits in feces?

  1. A. 100 ml
  2. B. 1000 ml
  3. C. 1500 ml
  4. D. 500 ml

Correct answer: A – 100 ml

Q20: Saliva contains which carbohydrate-digesting enzyme?

  1. A. Pepsin
  2. B. Amylase
  3. C. Trypsin
  4. D. Lipase

Correct answer: A – Pepsin

Q21: Proteins are primarily digested to and absorbed as

  1. A. Amino acids
  2. B. Glycerides
  3. C. Nucleic acids
  4. D. Fatty acids

Correct answer: A – Amino acids

Q22: The major chemical digestive activity in the stomach is

  1. A. Starch breakdown
  2. B. Protein breakdown
  3. C. Fat breakdown
  4. D. Fibre breakdown

Correct answer: A – Starch breakdown

Q23: Which is true about pancreatic secretions?

  1. A. CCK causes bicarbonate release
  2. B. Secretin causes enzyme release
  3. C. Gastrin stimulates enzyme release
  4. D. CCK stimulates enzyme release

Correct answer: A – CCK causes bicarbonate release

Q24: The hormone that inhibits gastric secretion and motility is

  1. A. Gastrin
  2. B. Histamine
  3. C. Secretin
  4. D. Pepsin

Correct answer: A – Gastrin

Q25: How are fat components absorbed in the small intestine?

  1. A. Receptor proteins carry fatty acids to bloodstream
  2. B. Fatty acids are actively transported
  3. C. Lipid components diffuse through enterocyte membranes
  4. D. Lipid components diffuse directly into liver bloodstream

Correct answer: A – Receptor proteins carry fatty acids to bloodstream

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