41.What substance protects the stomach lining from damage due to digestive juices?

a.water

b.mucus

c.pepsinogen

d.dietary fats

42.Which is an example of a role of hydrochloric acid in the gastrointestinal tract?

a.It kills bacteria.

b.It activates pancreatic enzymes.

c.It raises the pH of chyme.

d.It promotes hydrolysis of dietary carbohydrate.

43.Which of these parts of the GI tract contains highly acidic digestive juices?

a.colon

b.ileum

c.stomach

d.duodenum

44.The usual pH of gastric juice is approximately which of the following values?

a.2

b.4

c.6

d.7

45.Which of these is an important function of mucus?

a.help solubilize bile

b.stabilize pancreatic enzymes

c.enhance absorption of vitamin B₁₂

d.protect the stomach walls from digestion

46.After a portion of food is chewed and swallowed, what happens to the salivary amylase in the stomach?

a.It is inactivated by gastric juice.

b.It continues to hydrolyze starches.

c.It binds to pepsin and catalyzes proteolytic activity.

d.It passes into the duodenum where the alkaline pH stimulates carbohydrase activity.

47.Which of the following body organs secretes digestive enzymes?

a.esophagus

b.gastric glands

c.liver

d.endocrine glands

48.The process by which bile acts on fat so enzymes can attack the fat is known as which of the following?

a.condensation

b.emulsification

c.enzymification

d.phosphorylation

49.Which of the following is is digested by pancreatic juice?

a.fats

b.fibre

c.zymogens

d.insulin

50.Which of the following is a component of pancreatic juice?

a.bile

b.HCl

c.lipase

d.emulsifier