Question

multiple choice 1 point
the bolus is liquefied in the ______ and it is now called chyme.
stomach
mouth
small intestine
esophagus
8
multiple choice 1 point
pepsinogen, an inactive digestive enzyme, is secreted by the ______.
chief cells of the stomach
goblet cells of the small intestine
brunners glands in the duodenum
parietal cells of the stomach

Explanation:

• For the first question:
• In the mouth, food is chewed and mixed with saliva to form a bolus.
• The esophagus is just a passage for the bolus to move from the mouth to the stomach.
• In the small intestine, digestion and absorption of nutrients from chyme (not formation of chyme from bolus) mainly occur.
• In the stomach, the bolus is mixed with gastric juices (like hydrochloric acid and pepsinogen which is activated to pepsin) and is liquefied to form chyme.
• For the second question:
• Goblet cells in the small intestine secrete mucus for lubrication.
• Brunner's glands in the duodenum secrete an alkaline mucus - rich secretion to neutralize stomach acid.
• Parietal cells of the stomach secrete hydrochloric acid.
• Chief cells of the stomach secrete pepsinogen (an inactive form of the digestive enzyme pepsin). When pepsinogen comes in contact with hydrochloric acid (secreted by parietal cells) in the stomach lumen, it is activated to pepsin which helps in protein digestion.

Answer:

1. stomach
2. chief cells of the stomach