In the mouth and stomach, salivary amylase initiates the digestion of which nutrients?
C.
Which elements in saliva protect against tooth decay?
A.
What effect is a result of inhibiting the parasympathetic nervous system with a drug such as atropine?
a. Salivation becomes thinner.
b. Salivation decreases.
c. The pH of saliva changes.
d. Digestive enzymes are inhibited.
ANS: B
The sympathetic and parasympathetic divisions of the autonomic nervous system control salivation. Because cholinergic parasympathetic fibers stimulate the salivary glands, atropine (an anticholinergic agent) inhibits salivation and makes the mouth dry.
Food enters the stomach via which sphincter?
D.
Which gastric cells secrete gastrin
B.
Which gastric cells secrete histamine?
D.
Which gastric cells secrete pepsinogen and lipase?
D.
Which gastric cells secrete hydrochloric acid and intrinsic factor?
C.
Which cells in the stomach secrete histamine?
D.
The presence of chyme in the duodenum stimulates which hormones?
D.
The movement of chyme from the stomach into the duodenum initiates the intestinal phase of secretion. The release of secretin and cholecystokinin stimulate pancreatic secretions and inhibit gastric secretions.
Which gastric hormone inhibits acid and pepsinogen secretion, as well as decrease the
release of gastrin?
C.
Which enzyme breaks down protein-forming polypeptides in the stomach?
B.
Exposure to which substance protects the mucosal barrier of the stomach?
D.
Prostaglandins and enterogastrones, such as gastric inhibitory peptide, somatostatin, and secretin, inhibit acid secretion
The ileum and jejunum are suspended by folds of the peritoneum that contain an extensive
vascular and nervous network. What are these folds called?
A.
Where in the small intestines are lymphocytes, plasma cells, and macrophages produced?
B.
The lamina propria, which is a connective tissue layer of the mucous membrane, lies
beneath the epithelial cells of the villi and contains lymphocytes, plasma cells, which
produce immunoglobulins, and macrophages
Why are water and electrolytes transported in both directions through tight junctions and intercellular spaces rather than across cell membranes?
a. The intercellular hydrostatic pressure is inadequate to push the water and
electrolytes across the cell membranes.
b. A balance of cations and ions among the electrolytes on each side of the cell
membranes cannot be maintained.
c. The epithelial cell membranes are formed of lipids that are hydrophobic and
therefore repel water.
d. Receptors on those cell membranes are occupied with a diffusion of amino acids
and monosaccharides.
C
Which statement best describes the gastrointestinal tract?
a. The gastrointestinal tract is a muscular tube that transports food from the mouth to
the stomach.
b. The gastrointestinal tract is a hollow tube that extends from the mouth to the anus.
c. The gastrointestinal tract is a baglike structure that propels partially digested food
(chyme).
d. The structure is 5 m long and consists of three segments.
B.
The gastrointestinal tract is a hollow tube that extends from the mouth to the anus. The esophagus is a muscular tube that transports food from the mouth to the stomach. The stomach is a baglike structure that secretes digestive juices, mixes and stores food, and propels partially digested food (chyme) into the duodenum. The small intestine is 5 m long and has three segments.
Glucose transport enhances the absorption of which electrolyte?
D.
Sodium passes through the tight junctions and is actively transported across cell membranes. Sodium and glucose share a common active transport carrier (sodium-glucose ligand transporter 1 [SGLT1]).
What process is capable of increasing both intrathoracic and intraabdominal pressure,
thereby facilitating defecation?
C.
The formation of water-soluble molecules to facilitate the absorption of the by-products of
lipid hydrolysis is accomplished by:
B.
The products of lipid hydrolysis must be made water soluble if they are to be efficiently absorbed from the intestinal lumen. The formation of water-soluble molecules is known as micelles
What is the primary source of physiologic iron?
C.
Which statement is incorrect regarding the characteristics of vitamin B12?
B.
Which water-soluble vitamin is absorbed by passive diffusion?
C.
What water-soluble vitamin depends on active-transport for micelle formation?
D.
Which vitamin facilitates the absorption of iron by the epithelial cells of the duodenum
and jejunum?
B.
What is the role of the normal intestinal bacterial flora?
B.
Kupffer cells are best described as:
B.
The sinusoids are lined with phagocytic cells, known as Kupffer cells, which are part of the mononuclear phagocyte system and are the largest population of tissue macrophages in the body.
Bilirubin is a by-product of the destruction of which aged cells?
D.
The process of conjugation of bilirubin in the liver is best described as which
transformation?
B.
Which statement is incorrect regarding gallbladder function?
A.
Within 30 minutes after eating, the gallbladder begins to contract and the sphincter of Oddi relaxes, forcing bile into the duodenum through the major duodenal papilla
Which structure synthesizes clotting factors and the vitamin K necessary for hemostasis?
D.
How many days does it take for the entire epithelial population of the small intestines to be
replaced?
A.
Which statement is true regarding the state of the intestinal tract at birth?
D.
The intestinal tract is sterile at birth but becomes colonized with Escherichia coli,
Clostridium welchii, and Streptococcus within a few hours
Gastric emptying is NOT delayed by the presence of which substance?
D.
Which statements are true regarding the gastroileal reflex? (Select all that apply.)
a. The purpose of gastroileal reflex is to inhibit gastric motility.
b. Ileum distension triggers the gastroileal reflex.
c. The gastroileal reflex causes the relaxation of the ileocecal sphincter.
d. Increased gastric secretion triggers the gastroileal reflex.
e. The gastroileal reflex stimulates an increase in ileal motility.
C, D, E
Which statements are true regarding the ileogastric reflex? (Select all that apply.)
a. The purpose of ileogastric reflex is to inhibit gastric motility.
b. Ileum distension triggers the ileogastric reflex.
c. The ileogastric reflex causes the relaxation of the ileocecal sphincter.
d. Increased gastric secretion triggers the ileogastric reflex.
e. The ileogastric reflex stimulates an increase in ileal motility.
ANS: A, B
The ileogastric reflex inhibits gastric motility when the ileum becomes distended. The gastroileal reflex which is activated by an increase in gastric motility and secretion, stimulates an increase in ileal motility and the relaxation of the ileocecal sphincter
Which hormones are involved in the relaxation of the stomach’s fundus during
swallowing?
D.
Swallowing causes the fundus to relax (receptive relaxation) to receive a bolus of food from the esophagus. Relaxation is coordinated by efferent, nonadrenergic, noncholinergic vagal fibers and, of the available options, is facilitated only by gastrin and cholecystokinin, two polypeptide hormones secreted by the gastrointestinal mucosa
Which hormones is NOT involved in regulating gastric motility by making the threshold potential of muscle fibers less negative?
A.
Gastrin and motilin (small intestine hormones) and the vagus nerve increase contraction by making the threshold potential of muscle fibers less negative. Sympathetic activity and secretin (another small intestine hormone) are inhibitory and make threshold potential
more negative.
What requirements are necessary for calcium to be absorbed through the ileum at
concentrations of less than 5 mmol/L? (Select all that apply.)
a. Receptor site on the ileum
b. Vitamin D3
c. Vitamin K
d. Carboxypeptidase
e. A carrier protein
ANS: B, E
At concentrations less than 5 mmol/L, calcium is transported actively across cell membranes, bound to a carrier protein. The carrier formation requires the presence of the active form of vitamin D3 (1,25-dihydroxyvitamin D).
Which water-soluble vitamins are dependent on sodium for absorption? (Select all that
apply.)
a. Pantothenic acid
b. Vitamin B1
c. Vitamin C
d. Vitamin B12
e. Folic acid
ANS: B, C, E
Which statement is incorrect regarding the functions of the pancreas?
C.
Enzymatic secretion follows, stimulated by cholecystokinin, which activates ACh from the vagus nerve and the release of ACh from pancreatic stellate cells.
Stimulates the gallbladder to eject bile and the pancreas to secrete alkaline fluid.
C.
Stimulates the pancreas to secrete alkaline pancreatic juices
D.
Delays gastric and small bowel emptying
C.
Decreases pancreatic and enzyme secretions.
C.
Enhances insulin release, lipolysis, and ketogenesis
E.
__________ can decrease the rate of secretion by increasing an exchange of sodium for potassium. Sodium and water are conserved and potassium is excreted.
B.
Which hormone delays gastric empying?
A.
Which neurotransmitter stimulates gut immune response and pain sensation?
C.
Which neurotransmitter stimulates pepsinogen and acid secretion
C.
_______ _______, a mucoprotein produced by parietal cells, combines with vitamin B12 in the stomach. It is required for the absorption of vitamin B12 by the ileum.
Intrinsic factor (IF)
_______ is NOT required for the intestinal absorption of glucose
B. Insulin
_______ is a protein synthesized by the liver that inhibits apical uptake of iron by enterocytes and modulates iron trafficking.
Hepcidin
Small intestinal ______ cells, located near the base of the crypts of Leiberkühn, produce defensins and other antimicrobial peptides and lysozymes important to mucosal immunity.
Paneth
Small intestinal _____ ______ (lymph nodules containing collections of lymphocytes, plasma cells, and macrophages) are most numerous in the ileum and produce antimicrobial peptides and IgA as a component of the gut-associated lymph tissue in the small intestine
Peyer patches
Author
BodeS
ID
362558
Card Set
CH.42 Structure and Function of the Digestive System