MP - Howell - 2/16 - Pancreatic & Salivary Function Flashcards Preview

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Flashcards in MP - Howell - 2/16 - Pancreatic & Salivary Function Deck (10)
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1

Which of the following is true about the secretion from the exocrine pancreas?

a. It has a higher CI- concentration than does plasma
b. It is stimulated by the presence of HCO3- in the duodenum
c. Pancreatic HCO3- is increased by gastrin
d. Pancreatic enzyme secretion is increased by cholecystokinin (CCK)
e. It is hypotonic

d. Pancreatic enzyme secretion is increased by cholecystokinin (CCK)

2

Cystic fibrosis (CF) is an inherited disorder of the exocrine glands, affecting children and young people. Mucus in the exocrine glands becomes thick and sticky and eventually blocks the ducts of these glands (especially in the pancreas, lungs, and liver), forming cysts. A primary disruption in the transfer of which ion across cell membranes occurs in CF leading to decreased secretion of fluid?

a. Calcium
b. Chloride
c. Phosphate
d. Potassium
e. Sodium

b. Chloride

Movement of chloride ions out of cells leads to secretion of fluid by cells. Cystic fibrosis (CF) is caused by abnormal chloride ion transport on the apical surface of epithelial cells in exocrine gland tissues. The CF transmembrane regulator (CFTR) protein functions both as a cyclic AMP-regulated Cl- channel and, as its name implies, a regulator of other ion channels. The fully processed form of CFTR is found in the plasma membrane of normal epithelia. Absence of CFTR at appropriate cellular sites is often part of the pathophysiology of CF. However, other mutations in the CF gene produce CFTR proteins that are fully processed but are nonfunctional or only partially functional at the appropriate cellular sites.

3

During a hepatic surgery, bile is sampled from the liver and then from the gallbladder. Compared with liver bile, how might the composition of the gallbladder contents differ?

a. Lower bile salt concentration
b. Lower fatty acid concentration
c. Lower cholesterol concentration
d. Higher bilirubin concentration
e. Higher Cl- concentration

d. Higher bilirubin concentration

4

To evaluate possible cholecystitis, cholecystokinin (CCK) is given during a cholescintigraphy procedure in which bile constituents are radioactively labeled, and biliary secretions tracked. What is the primary function of CCK in this test?

a. To decrease primary bile salt formation
b. To decrease secondary bile salt formation
c. To stimulate local sympathetic efferents
d. To inhibit bicarbonate secretion
e. To contract the gallbladder

e. To contract the gallbladder

Cholecystokinin (CCK) has several roles in gastrointestinal function, including to facilitate bile release into the intestinal lumen. Release is effected by relaxing the sphincter of Oddi and contracting the gallbladder. CCK also increases HCO3- secretion. Bile release is also stimulated by parasympathetic nervous system acetylcholine release. The sympathetic nervous system does not contribute to bile release, and norepinephrine is classified as an inhibitor of bile secretion. CCK does not regulate bile salt formation.

5

With regard to the micelle, which of the following is correct?

a. a structure with a small polymolecular aggregate containing bile salts, monoglycerides, and fatty acids as its major constituents
b. the volume of a fat droplet
c. frequently seen inside the cells that line the intestine
d. a structure that slows lipid absorption
e. a structure that inhibits the saturation of the chyme with fatty acids and monoglycerides

a. a structure with a small polymolecular aggregate containing bile salts, monoglycerides, and fatty acids as its major constituents

The micelle is an intraluminal structure that speeds absorption of fatty acids and monoglycerides by delivering its contents to the outer surface of the intestinal epithelial cell. Fatty acids and monoglycerides are absorbed chiefly by the epithelial cells of the duodenum and jejunum. Most of the conjugated bile salts, on the other hand, are absorbed in the terminal ileum. The micelle may also contain fat-soluble vitamins and cholesterol. It has a diameter of 4-6 μm.

6

Which of the following statements is correct?

a. the bile acids, cholic and chenodeoxycholic acid, are synthesized in duodenal cells from cholesterol
b. bile acids are changed in the liver to deoxycholic and lithocholic acids
c. many microorganisms in the intestine conjugate taurocholic and glycocholic acid
d. bile acids are much more effective detergents than their conjugated salts
e. bacterial overgrowth in the small intestine can cause a decreased fat absorption

e. bacterial overgrowth in the small intestine can cause a decreased fat absorption

7

Which of the following statements is correct?

a. over 90% of the bile salt pool is lost each day
b. under 10% of the bile salt pool is lost each day
c. removal of the terminal ileum causes an increased synthesis of bile salts by the liver
d. if over 25% of the bile salts are lost each day, the bile salt pool will decrease
e. loss to the feces of all or most of the bile salts each day causes constipation

c. removal of the terminal ileum causes an increased synthesis of bile salts by the liver

8

Which of the following statements is correct?

a. the gallbladder normally has a capacity of greater than 600 mL
b. bile pigments, bile salts, and cholesterol may be twice as concentrated in the healthy gallbladder than in the hepatic duct
c. bile in the gallbladder has a lower concentration of sodium than in the hepatic duct
d. in the normal subject, all bile in the hepatic duct passes to the gallbladder
e. the gallbladder will contract in response to emotional stimuli such as hostility, as well as in response to food in the mouth

e. the gallbladder will contract in response to emotional stimuli such as hostility, as well as in response to food in the mouth

Bile may move from the hepatic ducts to the common hepatic duct past the cystic duct and into the bile duct and duodenum. In the adult, gallbladder capacity varies between 14 and 60 mL. The gallbladder, by means of the active transport of Na+, Cl-, and HCO3- removes water from the bile and modified the pH of the bile. Its high concentration of sodium results from the sodium being held in association with bile salts in osmotically inactive micelles. The concentration of sodium in gallbladder bile is approximately twice that in hepatic duct bile. The gallbladder, like the stomach, responds to cephalic stimuli.

9

Which of the following hormones are produced by duodenal cells and increase either the volume or the enzyme content of the exocrine secretion of the pancreas?

a. secretin
b. aldosterone
c. gastrin
d. cholecystokinin (pancreozymin)
e. secretin and cholecystokinin

e. secretin and cholecystokinin

10

Chymotrypsinogen:

a. is secreted primarily by the stomach
b. is converted to chymotrypsin by the action of trypsin
c. is converted to chymotrypsin by the an agent, gastrin, which decreases bile action of acid
d. uses starch as its primary substrate
e. uses triglycerides as its primary substrate

b. is converted to chymotrypsin by the action of trypsin

The precursor to trypsin (trypsinogen) is also secreted by the pancreas. Chymotrypsinogen is secreted by the pancreatic acinar cells. Trypsin and chymotrypsin reduce polypeptides to smaller peptides