25 Questions
What is the relationship between salivary bicarbonate concentration and plasma bicarbonate concentration at high flow rates?
Salivary bicarbonate is higher than plasma bicarbonate.
Which enzyme in saliva can hydrolyze triglycerides without the help of bile salts?
Lingual lipase
What is the primary regulation of salivary gland secretion?
Sympathetic nervous system
What is the pH range in which salivary alpha-amylase is active?
4-11
How do the sodium and chloride concentrations in saliva compare to those in plasma?
Saliva has lower Na+ and Cl- concentrations than plasma.
What is the primary role of the sympathetic nervous system in the gastrointestinal tract?
Inhibits motor and secretory activities
What percentage of water is absorbed by the small intestine?
78%
What is the most important function of saliva in the oral cavity?
To maintain a pH of around 7
How does the flow rate of saliva affect its pH?
Higher flow rate leads to higher pH (more basic)
Which ion in saliva is affected the most by changes in flow rate?
Bicarbonate (HCO3-)
Which hormone is responsible for stimulating the secretion of intrinsic factor in the stomach?
Gastrin
What is the primary function of the superior cervical ganglion in the regulation of salivary secretion?
Release norepinephrine
In the stomach, what triggers the receptive relaxation that allows for food storage?
Presence of food
Which of the following inhibits the pathway that leads to salivary gland secretion?
Dehydration
What is the role of pancreatic bicarbonate production in the digestive process?
Neutralize stomach acid
During which phase of secretion does food enter the duodenum and activate chemo- and mechanoreceptors in the mucosa?
Intestinal phase
What is the process called when bile acids are actively absorbed at the ileum and return to the liver via the portal circulation?
Enterohepatic circulation
Which nervous system pathway controls gastric secretion during the cephalic phase when there is no food in the stomach yet?
Parasympathetic pathway
Which phase occurs before food enters the stomach and involves thinking about food or smelling food?
Cephalic phase
Which portion of the small intestine acts as the site where bile acids are absorbed and returned to the liver?
Ileum
What is the primary hormone responsible for activating the parietal cells in the stomach?
Gastrin
Which of the following receptors in the stomach are activated by food distension and stimulate the release of acetylcholine?
Mechano/stretch receptors
In the gastric phase, what is released by G cells in response to distension of the stomach?
Gastrin
What is the role of gastrin in the gastric phase of digestion?
Stimulate parietal cells to produce HCl
Which of the following hormones is NOT involved in the regulation of salivary secretion?
Gastrin
Learn about the composition of ions in saliva relative to plasma. Understand the differences in Na+, Cl-, K+, and HCO3- concentrations between saliva and plasma at different flow rates.
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