NMS 2001 Gastrointestinal p553-558 Flashcards
The major stimulus for primary peristalsis in the esophagus is
swallowing
What secretion is most dependent on vagal stimulation?
Saliva. (salivary flow is entirely dependent on the autonomic nervous system. vagal stimulation produces a large volume of watery fluid, while sympathetic stimulation causes the secretion of proteins i.e. mucous and some enzymes)
What will inhibit stomach contractions?
Secretin
Gastric acid secretion increases when food enters the stomach because
protein digestion products directly stimulate the parietal cells to release HCl and food raises the pH of the stomach, allowing more acid to be released.
Gastric parietal cells secrete
intrinsic factor
What can occur without brain stem coordination?
gastric emptying
The major stimulus for gastric acid (HCl) secretion during the cephalic phase is
acetylcholine (ACh)
The major stimulus for the release of secretin is
HCl
Fats are transported from intestinal cells to blood plasma primarily in the form of
chylomicrons
Acetylcholine (ACh) is required for the contraction of
the upper esophageal sphincter
The major stimulus for receptive relaxation of the stomach is
food in the stomach
The motility pattern primarily responsible for the propulsion of chyme along the small intestine is
segmentation
Gastric acid (HCl) secretion is inhibited by
somatostatin
The major factor controlling the secretion of bile salts from the liver is the amount of
Bile reabsorbed from the intestine. (the amount of bile synthesized each day is not sufficient to absorb all of the fat digested. However, because the bile salts are absorbed by the intestine and returned to the liver, they can be used over and over again. The amount of bile secreted each day is thus proportional to the amount absorbed from the intestine.)
Micelle formation is necessary for absorption of
cholesterol
Na+ dependent transport is responsible for the absorption of; amino acids, glucose, and bile salts, but is not responsible for the absorption of
vitamin E
Intestinal motility is increased by; cholecystokinin (CCK), gastrin, insulin, and motilin however, it is not increased by
secretin
Cholecystokinin (CCK) secretion is stimulated by
amino acids, fatty acids, and bile salts. HCl does not stimulate the secretion of CCK.
List three effects that are caused by secretin
stimulation of pancreatic bicarbonate (HCO3-) secretion, potentiation of pancreatic enzyme secretion by cholecystokinin (CCK), and inhibition of gastric muscle contraction. the enhancement of bile acid secretion is NOT an effect caused by secretin.
A Na+ dependent active transport system is necessary for the intestinal absorption of
dipeptides, bile salts, vitamin C, and glucose. the intestinal absorption of fructose is NOT dependent on a Na+ active transport system.
What stimulus is most important for the regulation of gastric acid (HCl) secretion?
histamine
What stimulus is most important for the regulation of gastrin secretion?
bombesin.
What stimulus is most important for the regulation of pancreatic enzyme ssecretion?
CCK
What stimulus is most important for the regulation of gallbladder emptying?
CCK
What stimulus is most important for the regulation of emptying of the intestine during the inter-digestive period?
Motilin
Where does the absorption of bile acids occur?
ileum of the intestine
Where does the secretion of gastrin occur?
Antrum of the stomach
Where does the secretion of intrinsic factor occur?
Fundus of the stomach
Where does the secretion of K+ occur?
colon
Where does the absorption of iron occur?
duodenum
