digestion in stomach

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What is the primary function of tonic contractions in the proximal part of the stomach?

To stimulate the autonomic nervous system

To increase the force of gastric smooth muscle contractions

To increase the secretion of gastric hormones

To generate a sustained compressive force that reduces the volume occupied by food (correct)

What is the role of rugae in the stomach mucosa?

To decrease the distensibility of the stomach

To increase the force of gastric smooth muscle contractions

To allow the stomach to expand as it becomes distended with food and liquid (correct)

To stimulate the secretion of gastric hormones

What type of relaxation is induced in the proximal part of the stomach upon entry of food from the esophagus?

Autorhythmic contraction

Tonic contraction

Receptive contraction

Receptive relaxation (correct)

What is the effect of sympathetic stimulation on the force of gastric smooth muscle contractions?

It reduces the force of gastric smooth muscle contractions Signup and view all the answers

What is the primary function of the proximal part of the stomach in gastric motility?

To store food and liquid Signup and view all the answers

Which part of the gastrointestinal tract is the most distensible?

Stomach Signup and view all the answers

What is the primary function of the mucus secreted by mucous cells in the gastric gland?

To protect the gastric mucosa from acid and enzymes Signup and view all the answers

Which type of cells in the gastric gland secrete a hormone that stimulates the parietal cells to secrete hydrochloric acid?

G cells Signup and view all the answers

What is the effect of vagal stimulation on gastrin secretion?

It increases gastrin secretion Signup and view all the answers

What is the mechanism by which gastrin secretion is reduced when a high amount of hydrochloric acid is present in the stomach?

Negative feedback mechanism Signup and view all the answers

What is the primary function of pepsinogen secreted by chief cells in the gastric gland?

To break down proteins into peptides Signup and view all the answers

Into which structure do the secretions from the exocrine cells of the gastric gland flow?

Canaliculus Signup and view all the answers

What is the primary role of carbonic anhydrase in the parietal cells?

To catalyze the formation of carbonic acid from H2O and CO2 Signup and view all the answers

What is the net result of the action of the Cl-/HCO3- antiporter in the parietal cell?

Increased concentration of Cl- ions in the parietal cell Signup and view all the answers

What is the purpose of the proton pump (H+/K+ ATPase) in the parietal cell?

To actively transport H+ ions into the stomach lumen Signup and view all the answers

How do HCO3- ions exit the parietal cell?

In exchange for Cl- ions through the Cl-/HCO3- antiporter Signup and view all the answers

What is the characteristic of the gastric juice compared to plasma?

Isotonic Signup and view all the answers

What is the typical pattern of gastric acid secretion throughout the day?

Lower in the morning and higher in the afternoon and evening Signup and view all the answers

Which of the following hormones is produced in the duodenum and inhibits gastric acid secretion?

Secretin Signup and view all the answers

What is the effect of acetylcholine on hydrochloric acid secretion?

Stimulation Signup and view all the answers

What is the primary role of hydrochloric acid in the gastrointestinal tract?

Killing microbes present in the food Signup and view all the answers

Which of the following neurotransmitters inhibits gastric acid secretion?

Somatostatin Signup and view all the answers

Where are the receptors for the five agents that regulate gastric acid secretion located?

Basolateral membrane of parietal cells Signup and view all the answers

At what pH range does gastric lipase operate best?

pH 5-6 Signup and view all the answers

Why is gastric lipase important in newborn infants?

Because gastric acid secretion is not fully established Signup and view all the answers

What happens to gastric lipase when it enters the duodenum?

It is inactivated by pancreatic proteases Signup and view all the answers

What is absorbed by the mucous cells of the stomach?

Water, ions, certain drugs, and alcohol Signup and view all the answers

What is the primary function of the stomach in terms of nutrient absorption?

To absorb a small amount of nutrients Signup and view all the answers

In patients with pancreatic insufficiency, what can gastric lipase do?

Partly compensate for the impaired digestion of fat Signup and view all the answers