Which enzyme begins the chemical digestion of starch in the mouth?
Salivary amylase
✓
Pepsin
Pancreatic lipase
Trypsin
Correct Answer
Salivary amylase
Salivary amylase starts breaking starch into smaller sugars while food is still being chewed. Pepsin begins protein digestion in the stomach. Pancreatic lipase digests fats in the small intestine. Trypsin is a pancreatic enzyme that digests protein.
Category: Oral Cavity and Swallowing
Question 2
When which structure relaxes at the wrong times, acidic stomach contents flow back into the esophagus and cause gastroesophageal reflux disease?
Upper esophageal sphincter
Lower esophageal sphincter
✓
Pyloric sphincter
Ileocecal valve
Correct Answer
Lower esophageal sphincter
The lower esophageal sphincter sits where the esophagus joins the stomach and normally stays closed except during swallowing. Upper esophageal sphincter dysfunction mainly raises the risk of aspiration rather than acid reflux. Pyloric sphincter controls the stomach outlet, not the entry. Ileocecal valve lies between the small and large intestines.
Category: Stomach Structure and Secretion
Question 3
Which structure regulates the passage of chyme from the stomach into the small intestine?
Lower esophageal sphincter
Ileocecal valve
Pyloric sphincter
✓
Internal anal sphincter
Correct Answer
Pyloric sphincter
The pyloric sphincter at the lower end of the stomach releases chyme into the duodenum a little at a time; when it works poorly, gastric emptying can be delayed or too rapid. Lower esophageal sphincter guards the entry to the stomach. Ileocecal valve controls flow into the large intestine. Internal anal sphincter helps control defecation.
Category: Stomach Structure and Secretion
Question 4
Which stomach cells secrete hydrochloric acid and intrinsic factor?
Chief cells
G cells
Goblet cells
Parietal cells
✓
Correct Answer
Parietal cells
Parietal cells use the proton pump to secrete hydrochloric acid and also release intrinsic factor, which vitamin B12 needs for absorption. Chief cells secrete pepsinogen. G cells release the hormone gastrin. Goblet cells secrete protective mucus.
Category: Stomach Structure and Secretion
Question 5
Which cells in the stomach release the hormone gastrin?
G cells
✓
Chief cells
Goblet cells
Parietal cells
Correct Answer
G cells
G cells release gastrin into the blood, and gastrin then stimulates the acid-secreting cells of the stomach. Chief cells secrete pepsinogen. Goblet cells secrete mucus. Parietal cells respond to gastrin by secreting acid; they do not make it.
Category: Stomach Structure and Secretion
Question 6
Seeing, smelling and tasting food increase stomach secretions before any food is swallowed. Which phase of digestion is this?
Gastric
Cephalic
✓
Intestinal
Absorptive
Correct Answer
Cephalic
The cephalic phase begins in the brain, which signals the stomach through the vagus nerve and acetylcholine to start secreting. Gastric describes the phase that begins when food enters the stomach. Intestinal describes the phase that begins when chyme reaches the small intestine. Absorptive refers to the period of nutrient uptake after a meal, not a phase of gastric secretion.
Category: Stomach Structure and Secretion
Question 7
The common bile duct and the pancreatic duct empty into which segment of the digestive tract?
Jejunum
Ileum
Duodenum
✓
Cecum
Correct Answer
Duodenum
Bile and pancreatic juice enter the duodenum, the first segment of the small intestine, where they neutralize acid and digest fats, proteins and carbohydrates. Jejunum is the middle segment of the small intestine. Ileum is the final segment of the small intestine. Cecum is the first part of the large intestine.
Category: Small Intestine and Absorption
Question 8
A patient who lacks which intestinal enzyme develops bloating, gas and diarrhea after drinking milk?
Maltase
Sucrase
Peptidase
Lactase
✓
Correct Answer
Lactase
Lactase on the small intestine lining splits lactose, the sugar in milk; undigested lactose draws water into the bowel and is fermented by colon bacteria. Maltase splits maltose. Sucrase splits table sugar. Peptidase breaks small peptides into amino acids.
Category: Small Intestine and Absorption
Question 9
Which pancreatic enzyme breaks down dietary proteins?
Trypsin
✓
Amylase
Lipase
Sucrase
Correct Answer
Trypsin
Trypsin, along with chymotrypsin, continues protein digestion in the small intestine. Amylase digests starch. Lipase digests fats. Sucrase is an intestinal enzyme that splits table sugar.
Category: Pancreas, Liver and Bile
Question 10
Which hormone, released when fatty chyme enters the small intestine, causes the gallbladder to contract?
Secretin
Cholecystokinin
✓
Gastrin
Insulin
Correct Answer
Cholecystokinin
Cholecystokinin causes the gallbladder to contract and release bile and also stimulates the pancreas to secrete digestive enzymes. Secretin mainly signals the pancreas to release bicarbonate. Gastrin stimulates stomach acid secretion. Insulin is a pancreatic hormone that lowers blood glucose.
Category: Pancreas, Liver and Bile
Question 11
Long courses of broad-spectrum antibiotics can strengthen the effect of warfarin partly by reducing colon bacteria that produce which vitamin?
Vitamin B12
Vitamin D
Vitamin K
✓
Vitamin C
Correct Answer
Vitamin K
Colon bacteria make vitamin K, which the liver needs to make several clotting factors, so losing these bacteria can raise the anticoagulant effect of warfarin. Vitamin B12 is absorbed with intrinsic factor and is not linked to warfarin response. Vitamin D is made in the skin and activated by the liver and kidneys. Vitamin C comes from the diet and does not affect clotting factor synthesis.
Category: Large Intestine
Question 12
Which structure controls the passage of contents from the small intestine into the large intestine?
Pyloric sphincter
Lower esophageal sphincter
Internal anal sphincter
Ileocecal valve
✓
Correct Answer
Ileocecal valve
The ileocecal valve lies between the ileum and the cecum and keeps colon contents from flowing back into the small intestine. Pyloric sphincter controls emptying of the stomach. Lower esophageal sphincter guards the entry to the stomach. Internal anal sphincter helps control defecation.
Category: Large Intestine
Question 13
In celiac disease, an immune reaction to which component of wheat, barley and rye damages the small intestine lining?
Gluten
✓
Lactose
Fructose
Casein
Correct Answer
Gluten
Gluten triggers an immune response that flattens the villi and causes malabsorption, so treatment is a strict gluten-free diet. Lactose is milk sugar. Fructose is a fruit sugar. Casein is a milk protein.
Category: GI Function and Disorders
Question 14
Which layer of the digestive tract wall contains the smooth muscle that mixes and propels its contents?
Mucosa
Muscularis externa
✓
Submucosa
Serosa
Correct Answer
Muscularis externa
The muscularis externa has circular and longitudinal smooth muscle layers, and in the stomach an extra oblique layer, that churn and propel contents. Mucosa is the inner lining that secretes and absorbs. Submucosa is connective tissue carrying blood vessels and nerves. Serosa is the thin outer covering.
Category: GI Function and Disorders
Question 15
The esophagus does not digest food. What does its lining secrete to ease the passage of food?
Pepsin
Bile
Mucus
✓
Amylase
Correct Answer
Mucus
The esophagus secretes mucus that lubricates the bolus as peristalsis carries it to the stomach. Pepsin is made in the stomach from pepsinogen. Bile is made by the liver. Amylase comes from the salivary glands and pancreas.
Category: Oral Cavity and Swallowing
Question 16
Chewing food and churning it in the stomach are examples of which process?
Chemical digestion
Absorption
Secretion
Mechanical digestion
✓
Correct Answer
Mechanical digestion
Mechanical digestion breaks food into smaller pieces physically, giving enzymes more surface to act on. Chemical digestion uses enzymes and acid to break chemical bonds. Absorption is the movement of nutrients into blood or lymph. Secretion is the release of fluids such as enzymes and mucus.
Category: GI Function and Disorders
Question 17
Which age-related change contributes to constipation in older adults?
Decreased peristalsis
✓
Increased gastric acid secretion
Faster gastric emptying
Increased saliva production
Correct Answer
Decreased peristalsis
With aging, peristalsis, motility and intestinal blood flow decline, so transit slows and more water is pulled from the stool. Increased gastric acid secretion does not slow the bowel. Faster gastric emptying would speed transit rather than slow it. Increased saliva production is not a typical age-related change and does not cause constipation.
Category: GI Function and Disorders
Question 18
Taste buds on the tongue detect sweet, salty, sour and bitter tastes, along with which savory taste?
Spicy
Umami
✓
Metallic
Astringent
Correct Answer
Umami
Umami is the savory taste produced by glutamate in foods such as broth, cheese and meat, and it is one of the basic tastes along with sweet, salty, sour and bitter. Spicy is a burning sensation carried by pain fibers, not a basic taste. Metallic is an altered taste that some drugs cause, not a basic taste. Astringent is a drying, puckering feel in the mouth rather than a taste.
Category: Oral Cavity and Swallowing
Question 19
Which fingerlike projections of the small intestine lining greatly enlarge its absorptive surface?
Rugae
Haustra
Villi
✓
Cilia
Correct Answer
Villi
Villi are highly vascular projections of the small intestine lining, each with blood capillaries and a lymphatic lacteal, which take up digested nutrients. Rugae are folds of the stomach lining that let it stretch. Haustra are pouches of the colon wall. Cilia are hairlike structures that move mucus in the airways.
Category: Small Intestine and Absorption
Question 20
Which substances does the large intestine mainly absorb?
Amino acids and peptides
Fatty acids and monoglycerides
Glucose and fructose
Water and electrolytes
✓
Correct Answer
Water and electrolytes
The large intestine absorbs water and electrolytes from undigested material and forms feces. Amino acids and peptides are absorbed in the small intestine. Fatty acids and monoglycerides from fat digestion are absorbed in the small intestine and reach the lymph through the lacteals. Glucose and fructose are absorbed in the small intestine.
Category: Large Intestine