The Digestive System
0Loading crowd target
0Loading crowd target
8correct to beat the crowd
Explore the fascinating world of human digestion with our comprehensive free 97-question trivia quiz with answers. From the mouth to the intestines, test your knowledge of how your body breaks down food and absorbs nutrients. Whether you're a biology student or simply curious about your digestive health, this quiz will challenge and educate you.
30 of 97 questions with answers and explanations. Play the quiz
Q 01At which blind pouch in the lower right abdomen does the large bowel begin?
Cecum
The cecum is the blind pouch where the large bowel begins; the appendix hangs from it in the right iliac region, which is why appendicitis pain settles in the lower right abdomen.
Q 02What enzyme in saliva begins the chemical digestion of carbohydrates?
Amylase
Amylase starts on starch in the mouth, but food leaves too soon for it to finish, so the pancreas sends more amylase into the small intestine.
Q 03Which small fleshy flap at the back of the mouth rises when you swallow to help keep food out of the nose?
Uvula
The uvula rises with the soft palate when you swallow, and it can also vibrate and add to the sound of snoring.
Q 04Which tissue covering the crown of a tooth is the hardest substance in the human body?
Enamel
Enamel is still vulnerable: bacteria in plaque turn sugar and starch into acids that eat away at it, causing tooth decay.
Q 05In a hiatal hernia, the upper part of the stomach bulges through an opening in which muscle?
Diaphragm
The diaphragm normally helps keep acid from rising out of the stomach, so a hiatal hernia makes reflux and heartburn more likely.
Q 06Which hormone signals the stomach to secrete more acid and increases its muscle contractions?
Gastrin
Gastrin is released as a meal reaches and stretches the stomach, so eating itself switches on more acid secretion.
Q 07What is the process of taking food into the body through the mouth called?
Ingestion
Ingestion hands food on to swallowing, which you control only at first; its throat and food-pipe stages then run automatically.
Q 08Pepsin is an enzyme primarily responsible for breaking down which type of macromolecule in the stomach?
Proteins
Pepsin breaks proteins into shorter peptides; the stomach secretes it as inactive pepsinogen, which gastric acid converts into the working enzyme.
Q 09Which compound, secreted by cells of its lining, makes the stomach strongly acidic?
Hydrochloric acid
Hydrochloric acid kills much of the bacteria swallowed with food and is needed to switch inactive pepsinogen into pepsin.
Q 10What is the scientific term for chewing, the process by which teeth crush and grind food?
Mastication
Mastication breaks food into smaller pieces with more surface area, so digestive enzymes can work on it faster.
Q 11Peyer's patches, immune tissue that guards against gut bacteria, are concentrated in which part of the gut?
Ileum
The ileum is where Peyer's patches are densest, so typhoid, which infects them, can perforate the gut wall there.
Q 12Which muscular ring at the stomach's entrance prevents acid reflux?
Lower esophageal sphincter
When the lower esophageal sphincter is weak or relaxes at the wrong time, stomach acid can back up and cause heartburn.
Q 13The absorption of vitamin B12 in the small intestine requires the presence of what gastric protein?
Intrinsic factor
Intrinsic factor lets vitamin B12 be absorbed, and a lack of B12 can cause anemia.
Q 21Bile salts emulsify fats into smaller droplets, increasing the surface area for which enzyme?
Lipase
Lipase work begins before the stomach: glands on the tongue release lingual lipase, which keeps digesting fat in the stomach.
Q 22The small intestine is longer than the large intestine, so why is it called 'small'?
It is narrower
It is narrower: the large intestine is more than twice as wide, even though the small intestine is several times longer.
Q 23What is the primary function of the epiglottis during swallowing?
Keep food out of the trachea
The epiglottis folds down over the larynx to keep food out of the trachea; if food gets in anyway, a cough reflex tries to force it out.
Q 14What organ stores bile produced by the liver?
Gallbladder
The gallbladder concentrates the bile it stores, yet people can live without one because bile has other ways to reach the intestine.
Q 15Which vitamin, partly made by bacteria in the colon, is needed for blood clotting?
Vitamin K
Newborns have very little vitamin K, so babies usually get a vitamin K shot soon after birth.
Q 16The churning action of the stomach walls is a form of what type of digestion?
Mechanical digestion
Mechanical digestion in the stomach relies on an extra inner oblique muscle layer, found nowhere else in the gut, that lets it churn food.
Q 17Which simple sugar is the main end product of carbohydrate digestion and the body's chief energy source?
Glucose
Glucose absorbed from the gut travels first to the liver through the hepatic portal vein, before reaching the rest of the body.
Q 18Which Russian physiologist won the 1904 Nobel Prize in medicine for his work on digestion?
Ivan Pavlov
Ivan Pavlov's digestion research led him to study conditioned reflexes, including his famous experiments on dogs.
Q 19Which duodenal hormone stimulates the pancreas to release bicarbonate-rich fluid?
Secretin
Secretin is released by S cells of the duodenum when acid arrives; it makes the pancreas secrete a bicarbonate-rich juice that neutralizes stomach acid in the small intestine.
Q 20Which lumps of lymphoid tissue at the back of the throat help trap germs coming in through the mouth?
Tonsils
Tonsils and adenoids trap germs, and when the tonsils become inflamed, usually from a virus, the result is tonsillitis.
Q 24What is the semi-fluid mass of partly digested food and digestive secretions that leaves the stomach?
Chyme
Chyme takes its name from the Greek for 'juice', and the stomach makes it by churning food with gastric juice in mixing waves.
Q 25Which cells in the stomach's glands secrete the acid in gastric juice?
Parietal cells
Parietal cells pump out acid with a proton pump, the same pump that proton-pump inhibitor drugs block to cut stomach acid.
Q 26What are the fat-absorbing lymphatic capillaries within the villi of the small bowel called?
Lacteals
Sugars and amino acids pass straight into the blood, but digested fats enter the lacteals and reach the blood through the lymphatic system.
Q 27What is the small, rounded mass of chewed food mixed with saliva, ready to be swallowed?
Bolus
While a bolus passes through the throat, breathing stops for a moment.
Q 28Which disease is an autoimmune reaction to gluten that damages the small bowel's villi?
Celiac disease
Celiac disease is an autoimmune response to gluten in which the immune system flattens the villi of the small bowel, impairing absorption; a strict gluten-free diet is the treatment.
Q 29Which section of the large bowel comes immediately after the transverse portion?
Descending colon
Strong waves sweep waste through the descending colon during or soon after meals, which is why eating can bring on the urge to use the toilet.
Q 30What are the enzymes anchored on the small bowel's microvilli that finish digesting sugars and peptides called?
Brush border enzymes
Brush border enzymes include enteropeptidase, which switches on trypsin and so activates the pancreas's digestive enzymes.