Question

The diagram shows part of the alimentary canal:
When food is present in __(i)__ the two structures ___(ii)__ and ___(iii)___ usually contain bile?

A. ḭ → D, ii → D, iii →B

B. ḭ → A, ii → B, iii →E

C. ḭ → A, ii → B, iii →D

D. ḭ → D, ii → B, iii →E

Answer 1

Hint: The food reaches the duodenum part of the small intestine and the pancreatic juice, bile and, eventually, the enzymes in the succus entericus work to complete the absorption of carbohydrates, proteins and fats.

Complete answer:
The alimentary canal begins with an anterior opening - the mouth, and it opens out posteriorly through the anus.

The mechanism of digestion starts with the mouth and the ingestion of food. The teeth play a significant role in chewing or actively breaking down food into tiny particles. Enzymes found in saliva are now beginning to chemically break down food. The oesophagus is a long tube connecting the mouth to the stomach. Using peristalsis, or wave-like smooth muscle contractions, the muscles of the oesophagus force the food to the stomach. Gastric juices, like stomach enzymes, act on the particles of the food and facilitate the process of digestion. Further digestion of food begins in the small intestine, where enzymes generated by the liver, the small intestine, and the pancreas facilitate the process of digestion. The secretions discharged to the small intestine are bile, pancreatic juices, and intestinal juice. The bile and pancreatic juice are released through the hepatopancreatic duct.

The labelling of the given figure is:
A - Stomach
B - Gall Bladder
C - Pancreas
D - Duodenum
E - Liver

Thus, the correct answer is option D i.e., i → D, ii → B, iii →E.

Note:The bile that is released to the duodenum includes bile pigments, bile salts, cholesterol and phospholipids, but no enzymes. Bile helps to emulsify fats, i.e to break down fats, and stimulates lipases.