Which of the following cell types in the stomach is not necessary for digestive purposes?

Which enzyme is involved in protein digestion?

The parietal cells of the stomach fundus are responsible for secreting which component of the gastric juices?

Which of the following enzymes would function best at a pH of 2?

Which of the following secrete hydrochloric acid (HCl)?

Which of the following stomach cells releases pepsinogen?

Which of the following is not a component of bile?

Which process of digestion incorrectly pairs the enzyme or compound with its function in the small intestine?

Passage:

In a fictional universe, a new life form is discovered that appears to have a number of similarities to humans. Since its discovery by humans, it has been studied with x-ray imaging, magnetic resonance imaging (MRI), computed tomography imaging (CT), as well as with blood chemistries and laboratory studies. Based upon such analyses, scientists have found that both structurally and functionally, this fictional species, called Lorempis marengis, is highly similar to humans. It has structures that appear similar to lungs that are active during respiration. It has a structure that is highly active at all times, especially so in different parts during different activities (similar to the human brain). It also appears to have a digestive tract with a mouth, esophagus, stomach, small intestine, large intestine, and anus that is assumed to carry out the same functions at the cellular level as the parts of the human digestive tract. Scientists are now hoping to continue studying the organism at the cellular level to confirm their assumption that the cellular functions are indeed similar to those of human tissues.

In one cellular study performed on the organism described in the preceding passage, Lorempis marengis, scientists discover cells called "betts cells," that they believe serve a very similar function to chief cells in the human stomach. If this is accurate, which of the following is directly produced by betts cells?

The parietal cells of the stomach are vital for both food digestion and as a defense mechanism against pathogens. When the parietal cells are not functioning properly, diseases such sepsis due to Clostridium difficile and malnutrition may occur. To keep the digestive system healthy, proper nutrition as well as a balanced diet is vital.

The parietal cells of the stomach secrete hydrochloric acid via the hormone gastrin. Gastrin is released when the stomach distends, via the presence of proteins and/or indirectly by the vagus nerve from the parasympathetic nervous system. Hydrochloric acid breaks down certain ingested food as well as activates certain zymogens for further digestion of macromolecules. The high acidity of the stomach due to the release of hydrochloric acid by parietal cells also destroys most pathogens. When the parietal cell is not functioning properly, opportunistic pathogens may create health problems.

Parietal cells also secrete intrinsic factor, a glycoprotein which binds to vitamin B12 to prevent destruction of the vitamin by the hydrochloric acid. Down the gastrointestinal tract, the vitamin is absorbed by the ileum of the small intestine. Vitamin B12 is essential for red blood cell production. A diet low in vitamin B12 may lead to anemia.

James wanted to learn how the vagus nerve is able to promote acid secretion in the stomach. He removed the stomach from an animal model and directly stimulated it. He administered the same voltage the vagus nerve typical sends out during an action potential. Which of the following results are expected?