25 Questions
What stimulates the parietal cells to release acid during the gastric phase?
Gastrin
Which hormone is released by G cells in response to distension in the stomach?
Gastrin
What is the role of stretch receptors in the stomach during the gastric phase?
Send signals to the brain
Which cells detect partially digested peptides and release gastrin during digestion?
G cells
What is the function of gastrin in the gastric phase?
Stimulate HCl release from parietal cells
What is the main function of the surface mucous cells in the cardiac/fundic regions of the stomach?
To secrete mucus and bicarbonate
Which cell type in the gastric pit of the antrum acts as a stem cell?
The mucus neck cells
What is the main function of the parietal cells in the stomach?
To secrete hydrochloric acid and intrinsic factor
Which hormone is secreted by the G cells in the gastric pit of the antrum?
Gastrin
What is the primary composition of the basal gastric secretion in the stomach?
Sodium, chloride, and potassium
What is the function of pancreatic bicarbonate production in the GI system?
To neutralize stomach acid
Which hormone controls the speed of smooth muscle contractions in the GI system?
Gastrin
During the intestinal phase of digestion, which of the following effects is observed?
Slowed gastric emptying
What is the primary function of the stomach in the GI system?
Sterilize food
How do nerves and hormones influence the processes in the GI system?
By controlling the speed of contractions, secretions, and absorption
What is one of the primary functions of the pancreas in relation to the stomach?
To neutralize the acidic chyme from the stomach
Which hormone is involved in stimulating salivary gland secretion?
Norepinephrine
What is the primary function of the intrinsic factor secreted by the stomach?
To facilitate vitamin B12 absorption in the intestine
Which region of the stomach is responsible for mechanical digestion?
All regions contribute to mechanical digestion
During the intestinal phase of digestion, what happens after the chyme leaves the stomach?
Pancreatic enzymes further break down proteins and fats
What is the primary function of parietal cells in the stomach?
To secrete hydrochloric acid (HCl) into the stomach lumen
How do parietal cells overcome the proton (H+) gradient between the plasma and stomach lumen?
By using a K+/H+ exchanger on the apical surface
What happens to the bicarbonate ions (HCO3-) produced during HCl secretion by parietal cells?
They are transported into the bloodstream via a HCO3-/Cl- exchanger
What is the primary role of the enzyme carbonic anhydrase II (CA II) in parietal cells?
To catalyze the conversion of CO2 and H2O into H2CO3
What is the primary source of energy for parietal cells to secrete hydrochloric acid (HCl)?
Oxidative phosphorylation in mitochondria
Learn about how acetylcholine binds to M3 receptors in salivary gland cells, leading to various physiological responses like secretion of saliva and vasodilation. Understand the factors that inhibit this pathway and the positive stimulation of salivary secretion by the nervous system.
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