Question 1

The secretion of the intrinsic factor occurs in :

Accepted Answer

The intrinsic factor is secreted by the parietal cells of the stomach. This glycoprotein is essential for the absorption of vitamin B12 in the small intestine.

Question 2

So-called hunger pangs :

Accepted Answer

Hunger pangs are more common when starvation is associated with hypoglycemia, as low blood sugar levels can trigger the sensation of hunger.

Question 3

Basal acid output is increased with which of the following :

Accepted Answer

Alkalinization of the antrum increases gastrin release, which in turn increases basal acid output. Acidification of the antrum, administration of an H2 receptor antagonist, and vagotomy all decrease acid production.

Question 4

The cephalic phase of gastric secretion :

Accepted Answer

The cephalic phase of gastric secretion is controlled by the vagus nerves, which are activated by the sight, smell, taste, or thought of food, stimulating gastric secretion before food reaches the stomach.

Question 5

Gastric HCL secretion :

Accepted Answer

Gastric HCl secretion plays a significant role in iron absorption by converting dietary iron into its soluble, ferrous form, which is more easily absorbed in the duodenum.

Question 6

The gastric peristalsis :

Accepted Answer

The answer of The gastric peristalsis :
...

Question 7

All of the following statements are untrue except:

Accepted Answer

Peptic ulcers can indeed heal following the removal of the pyloric antrum, as this procedure can reduce the production of gastric acid by removing the area of the stomach that produces a significant amount of gastrin, a hormone that stimulates acid secretion. This reduction in acid can allow the ulcer to heal. The other options are incorrect: anticholinesterase drugs are not typically used to treat peptic ulcers (they can actually worsen symptoms by increasing gastric acid secretion), gastric secretion in response to hypoglycemia is not primarily due to gastrin, and vomiting is primarily a function of skeletal muscle activity (the act of vomiting is controlled by the brain and involves the coordinated contraction of skeletal muscles, not smooth muscles).

Question 8

Which of the following statement is true?:

Accepted Answer

The intrinsic factor, which is crucial for the absorption of vitamin B12 in the small intestine, is indeed secreted by the parietal cells of the gastric mucosa. This is a key component in the digestive process and is necessary for proper nutrition.

Question 9

Under normal condition, the gastric secretion is:

Accepted Answer

Gastric secretion is increased by the distention of the stomach. This is because the presence of food in the stomach stretches its walls, triggering the gastric phase of digestion, which involves the release of gastric juices to aid in the breakdown of food.

Question 10

About pepsins:

Accepted Answer

Pepsins are a group of proteolytic enzymes that work optimally in the acidic environment of the stomach, with an optimum pH range of 1.6 to 3.2. They are not exopeptidases (which cleave amino acids from the ends of peptides) but are endopeptidases, breaking peptide bonds within the chain. They are secreted as inactive precursors called pepsinogens, which are activated to pepsins in the acidic environment of the stomach, demonstrating their capability for autoactivation.

Question 11

The stomach is a poor area for absorption primarily because:

Accepted Answer

The stomach lacks villous membranes, which are crucial for absorption in the intestines. Villi increase the surface area for absorption, and their absence in the stomach makes it a poor area for absorbing most nutrients.

Question 12

Hydrochloric acid secretion:

Accepted Answer

Hydrochloric acid secretion in the stomach involves the active transport of hydrogen ions (H+) into the gastric lumen. This process is facilitated by the enzyme H+/K+ ATPase (proton pump) which exchanges potassium ions (K+) from the gastric lumen with hydrogen ions from the parietal cells. This requires energy and is not a passive process, nor does it rely on anaerobic metabolism. The remaining hydroxide ions (OH-) in the parietal cells can combine with carbon dioxide to form bicarbonate and water, which are then transported back into the blood, rather than being neutralized by protein molecules within the cells.

Question 13

A 45 years old man is found to have a condition in which the parietal cells of his stomach have been destroyed by an autoimmune mechanism. This condition is often associated with which of the following?:

Accepted Answer

Pernicious anemia is often associated with the destruction of parietal cells by an autoimmune mechanism, as these cells are responsible for the production of intrinsic factor, which is necessary for the absorption of vitamin B12. Without intrinsic factor, vitamin B12 cannot be absorbed, leading to pernicious anemia.

Question 14

It's believed that in parietal cells of the gastric mucosa (which secrete hydrochloric acid), an active transport system is responsible for the transmembrane passage of:

Accepted Answer

Parietal cells use an active transport system to secrete hydrochloric acid, which involves the movement of chloride ions across the cell membrane.

Question 15

Pepsin, secreted by the gastric mucosa:

Accepted Answer

Pepsin is synthesized within the chief cells of the stomach as an inactive precursor called pepsinogen, which is then activated to pepsin in the acidic environment of the stomach.

Question 16

Acid secretion in ulcer disease can be reduced by which of the following?

Accepted Answer

Blockage of histamine H2 receptors reduces acid secretion in the stomach, which is beneficial in treating ulcer disease.

Question 17

The normally innervated stomach :

Accepted Answer

Chewing food stimulates the cephalic phase of gastric secretion through neural pathways, leading to gastric juice secretion even if the food is not swallowed.

Question 18

Under the normal conditions, the bulk of gastric secretions are produces:

Accepted Answer

The majority of gastric secretions are produced while food is in the stomach. This is because the presence of food stimulates the stomach to produce gastric juices, which are necessary for the digestion of food. This phase of gastric secretion is known as the gastric phase and is responsible for about 70% of the total volume of gastric juice produced.

Question 19

Mucous presents on the surface of the mucosa of the stomach,smal and large intestine is:

Accepted Answer

Mucous on the surface of the mucosa in the gastrointestinal tract, including the stomach, small intestine, and large intestine, is resistant to the enzymes secreted into the lumen. This resistance helps protect the mucosal lining from digestive enzymes and the acidic environment, especially in the stomach.

Question 20

The enterogastric reflex can be elicted by which of the following?:

Accepted Answer

The enterogastric reflex is triggered by several factors including the distension of the duodenum, the presence of acid chime, and hyperosmotic chime in the duodenum. This reflex helps regulate the rate at which the stomach empties its contents into the small intestine, ensuring optimal digestion and absorption.

Quiz 3: Gastric Secretion and Functioning of the Stomach