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Explore the fascinating world of human digestion with our comprehensive free 49-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 49 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, also known as ptyalin in saliva, starts breaking starches into simpler sugars before food is even swallowed.
Q 03What type of muscular contractions move food through the digestive tract?
Peristalsis
Peristalsis refers to the wave-like muscular contractions that propel food through the esophagus, stomach, and intestines, facilitating its movement along the alimentary canal.
Q 04Which accessory organ is responsible for producing bile?
Liver
The liver makes bile, an alkaline fluid containing cholesterol and bile acids; the gallbladder only stores it.
Q 05Where does most chemical digestion and nutrient absorption primarily occur?
Small intestine
The small intestine is the primary site where the majority of chemical digestion takes place and where most nutrients are absorbed into the bloodstream.
Q 06Which structures lining the small bowel greatly increase its surface area for absorption?
Villi
Villi are finger-like projections about a millimetre tall that multiply the small bowel's absorptive area, and the microvilli on their surface multiply it again; rugae and haustra are folds of the stomach and large bowel.
Q 07What hormone stimulates the release of gastric acid and promotes stomach muscle contractions?
Gastrin
Gastrin is a peptide hormone produced by G cells in the stomach and small intestine, primarily stimulating the secretion of hydrochloric acid by parietal cells and increasing gastric motility.
Q 08What is the process of taking food into the body through the mouth called?
Ingestion
Ingestion is the intake of food through the mouth, the first stage of digestion; deglutition is the swallowing that follows, and egestion is the expulsion of undigested waste.
Q 09Pepsin 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 10Which compound, secreted by cells of its lining, makes the stomach strongly acidic?
Hydrochloric acid
Hydrochloric acid from the stomach lining makes gastric juice far more acidic than any other body fluid, killing most swallowed microbes and converting pepsinogen into active pepsin.
Q 11What is the scientific term for chewing, the process by which teeth crush and grind food?
Mastication
Mastication is chewing; the masseter and temporalis muscles drive the lower jaw so the molars crush and grind food while saliva moistens it for swallowing.
Q 12Peyer's patches, key to immune surveillance, are mainly in which part of the small intestine?
Ileum
Peyer's patches are clusters of lymphoid follicles densest in the ileum, the last part of the small intestine; they are named for the 17th-century Swiss anatomist Johann Conrad Peyer.
Q 13Which muscular ring at the stomach's entrance prevents acid reflux?
Lower esophageal sphincter
Q 21Which 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 22After swallowing, food travels down which muscular tube to reach the stomach?
Esophagus
The esophagus, which propels food from the pharynx to the stomach by peristalsis; in some birds it widens into a crop for storing food.
Q 23Bile salts emulsify fats into smaller droplets, increasing the surface area for which enzyme?
Lipase
Bile salts emulsify dietary fats, increasing the surface area for lipase enzymes (like pancreatic lipase) to efficiently break them down into fatty acids and monoglycerides.
The lower esophageal sphincter (LES) is a muscular ring at the junction of the esophagus and stomach that relaxes to allow food passage and contracts to prevent reflux of stomach acid.
Q 14The absorption of vitamin B12 in the small intestine requires the presence of what gastric protein?
Intrinsic factor
Intrinsic factor is a glycoprotein secreted by the parietal cells in the stomach that is essential for the absorption of vitamin B12 in the distal ileum of the small intestine.
Q 15After leaving the stomach, food enters which part of the digestive tract?
Duodenum
The duodenum, the C-shaped first section of the small intestine about 25 cm long, receives food leaving the stomach together with bile and pancreatic juice.
Q 16What organ stores bile produced by the liver?
Gallbladder
The gallbladder is a small organ that stores and concentrates bile produced by the liver before releasing it into the small intestine to aid in fat digestion.
Q 17Which vitamin, partly made by bacteria in the colon, is needed for blood clotting?
Vitamin K
Vitamin K is produced in part by bacteria in the large intestine and is required by the liver to make clotting factors, including prothrombin.
Q 18The churning action of the stomach walls is a form of what type of digestion?
Mechanical digestion
The churning and mixing of food by the muscular walls of the stomach is a form of mechanical digestion, which physically breaks down food into smaller pieces.
Q 19Which simple sugar is the main end product of carbohydrate digestion and the body's chief energy source?
Glucose
Glucose is the sugar most cells burn to make ATP; starch and glycogen are chains of it, and plants polymerise it into cellulose, the most abundant carbohydrate on Earth.
Q 20Which gland, tucked behind the stomach, produces both digestive enzymes and hormones such as insulin?
Pancreas
The pancreas does two jobs: exocrine, producing digestive enzymes, and endocrine, secreting hormones like insulin and glucagon.
Q 24The 'small' bowel is actually longer than the large one; roughly how long is it in an adult?
6.5 metres
At about 6.5 metres the small bowel is roughly four times the length of the large bowel; it is called 'small' only because it is narrower, and it folds many times to fit the abdomen.
Q 25What is the primary function of the epiglottis during swallowing?
Keep food out of the trachea
The epiglottis, a leaf-shaped flap of cartilage, folds down over the larynx during a swallow to keep food out of the trachea; food entering the airway is called aspiration.
Q 26What is the semi-fluid mass of partly digested food and digestive secretions that leaves the stomach?
Chyme
Chyme is the acidic, semi-fluid mixture of partially digested food and gastric juices that is formed in the stomach and slowly released into the small intestine.
Q 27Which cells in the stomach lining are responsible for producing hydrochloric acid?
Parietal cells
Parietal cells, also known as oxyntic cells, secrete both hydrochloric acid and intrinsic factor.
Q 28What are the fat-absorbing lymphatic capillaries within the villi of the small bowel called?
Lacteals
Lacteals are the lymphatic capillaries in each villus that take up fats packaged as chylomicrons; the milky fluid, chyle, gives them their name, from the Latin for milk.
Q 29What is the small, rounded mass of chewed food mixed with saliva, ready to be swallowed?
Bolus
A bolus is a soft, rounded mass of chewed food that has been mixed with saliva, prepared for swallowing and passage down the esophagus.
Q 30Which 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.