GI Anatomy and Physiology Review Practice Questions

25 multiple-choice questions on GI anatomy and physiology review for paramedic and EMT students, from Chapter 21 (Abdominal and Gastrointestinal Emergencies). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. Which organs are accessory organs of digestion rather than part of the alimentary canal?

   1. A. Liver, gallbladder, pancreas
   2. B. Stomach, duodenum, and jejunum
   3. C. Esophagus, stomach, and colon
   4. D. Spleen, liver, and kidneys
   Show answer

   Answer: A. Liver, gallbladder, pancreas

   Accessory organs make or store secretions (bile, enzymes) that drain into the alimentary canal, but food never passes through them. The spleen and kidneys are not digestive organs.

2. A peptic ulcer on the back wall of the duodenum can cause massive bleeding because it may erode into the:

   1. A. Inferior vena cava
   2. B. Superior mesenteric vein
   3. C. Gastroduodenal artery
   4. D. Left gastric vein
   Show answer

   Answer: C. Gastroduodenal artery

   The gastroduodenal artery runs directly behind the first part of the duodenum, so a posterior ulcer can erode into it and cause brisk arterial bleeding. The left gastric vein feeds varices in portal hypertension, not ulcer bleeding, and the IVC and SMV do not lie against the duodenal bulb.

3. A patient with a ruptured spleen complains of left shoulder pain. This is best explained by:

   1. A. Fractured left clavicle
   2. B. Spasm of the splenic artery wall
   3. C. Irritation of the left kidney
   4. D. Blood irritating the diaphragm
   Show answer

   Answer: D. Blood irritating the diaphragm

   Blood under the left hemidiaphragm irritates the phrenic nerve, and the brain reads it as left shoulder pain (Kehr sign). The kidney and clavicle are not part of this referral pattern.

4. Compared with a hollow organ injury, a solid abdominal organ injury most often causes:

   1. A. Early chemical peritonitis
   2. B. Severe bleeding and shock
   3. C. Spilled bowel contents
   4. D. Free air under the diaphragm
   Show answer

   Answer: B. Severe bleeding and shock

   Solid organs (liver, spleen, kidneys, pancreas) are very vascular and bleed. Hollow organs spill their contents, causing peritonitis and free air.

5. The ligament of Treitz is the landmark that divides the:

   1. A. Stomach from esophagus
   2. B. Small from large intestine
   3. C. Liver from gallbladder
   4. D. Upper from lower GI tract
   Show answer

   Answer: D. Upper from lower GI tract

   Bleeding proximal to the ligament of Treitz (esophagus, stomach, duodenum) is an upper GI bleed; distal to it is lower GI. The ileocecal valve divides small from large intestine.

6. After much of his terminal ileum was removed for Crohn disease, a patient is most likely to need lifelong:

   1. A. Vitamin B12 injections
   2. B. Pancreatic enzyme capsules
   3. C. Daily insulin injections
   4. D. Iron infusions every month
   Show answer

   Answer: A. Vitamin B12 injections

   Vitamin B12 bound to intrinsic factor is absorbed in the terminal ileum, so ileal resection leads to B12 deficiency that is treated with injections. Iron is absorbed mainly in the duodenum, and pancreatic enzymes and insulin are pancreatic, not ileal, functions.

7. A nursing home resident often needs the toilet within about 30 minutes of eating. This is explained by the:

   1. A. Cushing reflex
   2. B. Gastrocolic reflex
   3. C. Hering-Breuer reflex
   4. D. Vasovagal reflex
   Show answer

   Answer: B. Gastrocolic reflex

   Stretch of the stomach by a meal triggers increased colon motility (the gastrocolic reflex), which is why bowel programs are often timed after meals. The vasovagal reflex causes fainting, the Hering-Breuer reflex limits lung inflation, and the Cushing reflex is a response to raised intracranial pressure.

8. A gallstone stuck where the common bile duct ends can also cause pancreatitis because:

   1. A. Bile normally digests the pancreas
   2. B. It blocks the splenic vein
   3. C. The two ducts share one outlet
   4. D. The stone blocks the hepatic artery
   Show answer

   Answer: C. The two ducts share one outlet

   The common bile duct and the main pancreatic duct usually join at the ampulla of Vater, so a stone there can back up pancreatic secretions and trigger gallstone pancreatitis. Bile does not normally digest pancreatic tissue, and a stone in the ampulla sits inside the duct system, so it does not block the splenic vein or the hepatic artery.

9. A patient whose gallbladder was removed years ago can still digest fat mainly because:

   1. A. The stomach takes over fat digestion
   2. B. The liver keeps secreting bile
   3. C. Fat is absorbed without digestion
   4. D. The spleen begins to store bile
   Show answer

   Answer: B. The liver keeps secreting bile

   The liver makes bile; the gallbladder only stores and concentrates it. After cholecystectomy, bile drips continuously into the duodenum, so fat digestion continues (sometimes with loose stools after fatty meals). The spleen does not store bile, and fat must still be emulsified and digested before absorption.

10. Loss of which pancreatic function causes diabetes?

    1. A. Endocrine insulin release
    2. B. Exocrine enzyme release
    3. C. Bicarbonate secretion into the gut
    4. D. Bile salt storage
    Show answer

    Answer: A. Endocrine insulin release

    The islets of Langerhans (endocrine) secrete insulin and glucagon. Loss of exocrine enzymes causes malabsorption and fatty stools, not diabetes.

11. A man with cirrhosis has swollen veins radiating outward from his navel. These veins reflect:

    1. A. A clot in the inferior vena cava
    2. B. Normal veins seen through ascites
    3. C. Blood bypassing a scarred liver
    4. D. An infection of the umbilical skin
    Show answer

    Answer: C. Blood bypassing a scarred liver

    Caput medusae forms when portal hypertension forces portal blood through collateral veins around the umbilicus to reach the systemic circulation. Ascites can stretch the skin, but the dilated radiating veins themselves are collaterals, not normal veins or infection.

12. Which abdominal organ receives blood from two sources, the portal vein and the hepatic artery?

    1. A. Spleen
    2. B. Pancreas
    3. C. Kidney
    4. D. Liver
    Show answer

    Answer: D. Liver

    The liver receives about three quarters of its blood from the portal vein and the rest from the hepatic artery, which helps protect it from infarction. The spleen, pancreas, and kidneys are drained by or supplied from single arterial systems and do not receive portal inflow.

13. Irritation of the parietal peritoneum produces pain that is:

    1. A. Dull and poorly localized
    2. B. Crampy and comes in waves
    3. C. Felt only in the back
    4. D. Sharp and well localized
    Show answer

    Answer: D. Sharp and well localized

    The parietal peritoneum has somatic nerves, so pain is sharp, localized, and worse with movement. Visceral pain from organ walls is dull, crampy, and vague.

14. When the appendix lies behind the cecum (retrocecal), appendicitis may cause:

    1. A. Left shoulder pain from the spleen
    2. B. Painless bloody diarrhea
    3. C. Flank or back pain more than RLQ pain
    4. D. A pulsating mass in the right lower area
    Show answer

    Answer: C. Flank or back pain more than RLQ pain

    A retrocecal appendix sits against the posterior wall and psoas, so pain may be felt in the right flank or back with little anterior RLQ tenderness, and the psoas sign may be positive. Left shoulder pain suggests diaphragm irritation from the spleen, and a pulsatile mass suggests an aneurysm.

15. The greater omentum helps limit the spread of infection after a perforation by:

    1. A. Walling off the inflamed area
    2. B. Neutralizing the spilled acid
    3. C. Pulling the bowel away from it
    4. D. Draining pus out through the navel
    Show answer

    Answer: A. Walling off the inflamed area

    The greater omentum is a fatty, mobile apron that migrates to sites of inflammation and adheres to them, helping wall off a perforated appendix or ulcer into a local abscess. It wraps around the inflamed area rather than pulling the bowel away, it does not neutralize spilled acid or bowel contents, and it does not drain pus out of the body.

16. A stab wound to the left upper quadrant is most likely to injure the:

    1. A. Liver and gallbladder
    2. B. Spleen and stomach
    3. C. Appendix and cecum
    4. D. Sigmoid colon and bladder
    Show answer

    Answer: B. Spleen and stomach

    The LUQ holds the spleen, stomach, tail of the pancreas, and splenic flexure. The liver and gallbladder are RUQ, the appendix is RLQ, and the sigmoid and bladder are lower.

17. Why can a stab wound at the level of the 6th rib injure the liver?

    1. A. The diaphragm rises to the 4th-5th ICS
    2. B. The liver lies above the diaphragm
    3. C. The lungs extend down into the upper abdomen
    4. D. The ribs do not cover the liver
    Show answer

    Answer: A. The diaphragm rises to the 4th-5th ICS

    On full exhalation the diaphragm rises to about the nipple line, so the liver and spleen sit under the lower ribs. A wound below the nipples can enter both cavities.

18. Which organ makes the enzymes that digest most dietary fat, protein, and starch?

    1. A. Gallbladder
    2. B. Pancreas
    3. C. Stomach
    4. D. Liver
    Show answer

    Answer: B. Pancreas

    The exocrine pancreas secretes lipase, proteases, and amylase into the duodenum. The liver makes bile (which emulsifies but does not digest fat), the gallbladder only stores bile, and the stomach begins protein digestion with pepsin but is not the main enzyme source.

19. Hydrochloric acid in the stomach mainly serves to:

    1. A. Absorb vitamins into the blood
    2. B. Emulsify dietary fat droplets
    3. C. Neutralize pancreatic enzymes
    4. D. Activate pepsin, kill microbes
    Show answer

    Answer: D. Activate pepsin, kill microbes

    Stomach acid converts pepsinogen to pepsin and destroys many ingested organisms. Fat emulsification is the job of bile.

20. Critically ill patients, such as those with major burns or head injury, can develop stress ulcers mainly because:

    1. A. H. pylori spreads between ICU patients
    2. B. IV fluids dilute the stomach mucus
    3. C. Low gut blood flow weakens the lining
    4. D. Feeding tubes scrape the stomach lining
    Show answer

    Answer: C. Low gut blood flow weakens the lining

    In shock and critical illness, blood is diverted away from the gut, so the stomach lining loses its protective blood flow and mucus and erodes (Curling ulcers in burns, Cushing ulcers in head injury). These ulcers are not spread by H. pylori between patients, IV fluids do not wash away the mucus layer, and feeding tubes are not the cause. Acid is still present, which is why ICU patients often receive acid suppression.

21. Which change common in older adults most contributes to constipation?

    1. A. Faster movement through the colon
    2. B. Less activity, fluid, and fiber
    3. C. Greater stomach acid output
    4. D. Larger rectal blood vessels
    Show answer

    Answer: B. Less activity, fluid, and fiber

    Older adults often move less, drink less, eat less fiber, and take constipating drugs such as opioids and anticholinergics, all of which slow stool transit. Faster colonic transit would cause diarrhea, not constipation, and stomach acid output does not drive constipation.

22. Dying bowel in mesenteric ischemia causes a metabolic acidosis mainly because:

    1. A. Ammonia from the dying bowel builds up
    2. B. Bile acids leak into the blood
    3. C. Ischemic tissue produces lactic acid
    4. D. The patient breathes too slowly
    Show answer

    Answer: C. Ischemic tissue produces lactic acid

    Without blood flow, bowel cells switch to anaerobic metabolism and produce lactic acid, so a rising lactate and acidosis are late, ominous signs. Slow breathing would cause a respiratory, not metabolic, acidosis, and bile acid leak is not the mechanism. Ammonia is a base, not an acid, so its buildup does not explain the metabolic acidosis.

23. Which LUQ organ is not part of the digestive system but bleeds heavily when injured?

    1. A. Pancreas
    2. B. Stomach
    3. C. Gallbladder
    4. D. Spleen
    Show answer

    Answer: D. Spleen

    The spleen is a lymphatic organ that filters blood. It is very vascular, so splenic injury is a major cause of hemorrhage after blunt trauma.

24. You see a gentle pulsation in the upper midline abdomen of a thin, healthy 24-year-old with no pain. This most likely represents:

    1. A. A normal aortic pulse
    2. B. A ruptured aortic aneurysm
    3. C. Bowel moving against a blockage
    4. D. A hernia through the diaphragm
    Show answer

    Answer: A. A normal aortic pulse

    In thin people the abdominal aorta lies close enough to the front wall that a midline epigastric pulsation is normal. A painful, expanding pulsatile mass in an older patient with risk factors is different and suggests an aneurysm; visible peristalsis is wave-like, not pulsatile.

25. Bilirubin, which turns the skin yellow in jaundice, comes from the:

    1. A. Overproduction of bile acids
    2. B. Fat stored inside the liver
    3. C. Infection of the gallbladder
    4. D. Breakdown of old red cells
    Show answer

    Answer: D. Breakdown of old red cells

    Heme from old red cells becomes bilirubin, which the liver processes and excretes in bile. Liver failure or bile duct blockage lets it build up in the blood.