Multiple Choice
Some aspects of the __________ phase of gastric secretion, which occur before food enters the stomach, may be considered conditioned reflexes.
1184
views
23. The Digestive System
The Stomach
Multiple Choice
Which of the following steps of vitamin B-12 absorption occurs in the stomach?
A
Binding of vitamin B-12 to intrinsic factor
B
Absorption of vitamin B-12 into the bloodstream
C
Transport of vitamin B-12 to the liver
D
Release of vitamin B-12 from food proteins
Verified step by step guidance1
Understand that vitamin B-12 absorption involves multiple steps occurring in different parts of the digestive system.
Recognize that the stomach plays a crucial role in the initial processing of vitamin B-12.
In the stomach, vitamin B-12 is released from food proteins due to the acidic environment and the action of pepsin, an enzyme that breaks down proteins.
Identify that intrinsic factor, a protein secreted by the stomach's parietal cells, will later bind to vitamin B-12, but this occurs after the vitamin is released from food proteins.
Note that the absorption of vitamin B-12 into the bloodstream and its transport to the liver occur later in the small intestine, not in the stomach.
Related Videos
Related Practice
