Free Human Digestive System MCQs with Answers

• A. mouth, pharynx, oesophagus, stomach, small intestine, large intestine
• B. mouth, oesophagus, pharynx, stomach, small intestine, large intestine
• C. mouth, stomach, pharynx, oesophagus, large intestine, small intestine
• D. mouth, pharynx, stomach, oesophagus, small intestine, large intestine

Explanation: Food passes through the pharynx before the oesophagus and the oesophagus before the stomach, and the small intestine always precedes the…

• A. jejunum, duodenum, ileum
• B. duodenum, jejunum, ileum
• C. ileum, jejunum, duodenum
• D. caecum, colon, rectum

Explanation: The duodenum receives bile and pancreatic juice, the jejunum continues digestion, and the ileum completes absorption before the large…

• A. trachea
• B. larynx
• C. oesophagus
• D. small intestine

Explanation: The oesophagus moves the bolus by waves of peristalsis in a matter of seconds.

• A. pyloric sphincter
• B. ileocaecal valve
• C. anal sphincter
• D. cardiac sphincter

Explanation: The cardiac sphincter opens to admit food and closes to stop acid reflux into the oesophagus.

• A. amylase
• B. pepsin
• C. trypsin
• D. lipase

Explanation: Salivary amylase starts splitting starch into maltose right in the mouth, which is why bread tastes sweet if chewed long enough.

• A. hard palate
• B. tongue
• C. pharynx
• D. epiglottis

Explanation: The tongue's muscles manipulate food during chewing and push the bolus backwards to trigger swallowing, while its taste buds sample it.

• A. dentine
• B. bone
• C. enamel
• D. cement

Explanation: Enamel caps the crown of the tooth with a layer of mineral crystals harder even than bone, enabling it to withstand years of grinding.

• A. amylase
• B. lipase
• C. maltase
• D. pepsin

Explanation: Pepsin breaks proteins into peptides in the strongly acidic stomach, working best near pH 2.

• A. is attached to both the liver and the stomach
• B. has both exocrine and endocrine functions
• C. stores bile between meals
• D. secretes hormones only

Explanation: Its ducts deliver digestive enzymes into the duodenum, an exocrine role, while its islets of Langerhans release insulin and glucagon into…

• A. gall bladder
• B. spleen
• C. kidney
• D. appendix

Explanation: The gall bladder holds bile between meals and squeezes it into the duodenum when fat arrives.

• A. contains a strong acid
• B. contains pepsin
• C. digests starch
• D. contains no digestive enzyme

Explanation: Bile helps fat digestion purely physically, by emulsifying large drops into tiny ones that lipase can attack.

• A. fatty acids and glycerol
• B. glucose
• C. amino acids
• D. maltose

Explanation: Proteases and peptidases cut polypeptides down to single amino acids, which are absorbed and rebuilt into the body's own proteins.

• A. glucose and water
• B. fatty acids and glycerol
• C. starch
• D. amino acids

Explanation: Lipase splits the three ester bonds of a triglyceride, releasing glycerol and three fatty acids.

• A. microvilli
• B. villi
• C. cilia
• D. flagella

Explanation: Microvilli multiply the absorptive surface a further twenty times beyond the villi themselves.

• A. heart
• B. kidneys
• C. lungs
• D. liver, by the hepatic portal vein

Explanation: The liver screens, stores and adjusts nutrients before they enter the general circulation, regulating glucose and detoxifying harmful…

• A. the large intestine absorbs too much water
• B. digestion proceeds too rapidly in the stomach
• C. the intestinal contents move too quickly for adequate water absorption
• D. the villi absorb too much glucose

Explanation: When contents rush through, the large intestine cannot reclaim enough water and the faeces stay liquid, risking dehydration.

• A. very rapid peristalsis
• B. slow movement of contents through the large intestine with excess water absorption
• C. excess secretion of bile
• D. overactivity of the salivary glands

Explanation: The longer contents linger, the more water is reabsorbed and the harder and drier the faeces become.

• A. calories and protein overall
• B. vitamin C only
• C. iron only
• D. iodine only

Explanation: Marasmus reflects total starvation, with loss of muscle and fat, while kwashiorkor is protein deficiency with adequate calories, causing…

• A. digestion
• B. assimilation
• C. absorption
• D. ingestion

Explanation: Ingestion is simply intake; digestion breaks food down, absorption moves the products into blood, and assimilation uses them in cells.

• A. digest cellulose
• B. kill every bacterium swallowed
• C. protect the stomach wall from acid and pepsin
• D. absorb glucose

Explanation: A layer of mucus shields the epithelium from hydrochloric acid and pepsin, which would otherwise digest the stomach itself.