Unit2: Ch 36- Structure and Function of the Gastrointestinal System (Porth's 5th Ed)

Question 1

A 55-year-old man has been diagnosed with a gastroesophageal reflux disease (GERD),
in which the function of his lower esophageal sphincter is compromised. Which of the
following consequences of this condition is most likely to occur?
A) Decreased absorption of ingested foods and fluids
B) Impaired control of the gastric emptying rate
C) Protrusion of the stomach or regurgitation of stomach contents into the esophagus
D) Inappropriate release of gastric enzymes

Answer 1

Ans: C
Feedback:
Given that the role of the lower esophageal sphincter is to control the exchange of foods
and fluids, a deficit is likely to allow the stomach contents, or the stomach itself, to
protrude into the esophagus. Absorption is unlikely to be directly affected, and the
sphincter is not responsible for controlling gastric emptying or enzyme secretion.

Question 2

Place the following components of the gastrointestinal tract in the chronological order
that a bolus of food would pass through them. Use all the options.
A) Ileum
B) Pylorus
C) Jejunum
D) Hiatus
E) Cecum
F) Duodenum

Answer 2

Ans: D, B, F, C, A, E
Feedback:
Ingested food and fluids enter the stomach through the hiatus, exit through the pylorus,
and pass through the three subdivisions of the small intestine: the duodenum, jejunum,
and ileum. The cecum is a component of the large bowel.

Question 3

While explaining to a group of nursing students what the function of the first mucosal
layer of the lower two thirds of the esophagus, the pathophysiology instructor mentions
which of the following functions? Select all that apply.
A) Secretion of mucus to lubricate and protect the inner surface of the alimentary
canal
B) Smooth muscle cells that facilitate movement of contents of the GI tract
C) Holding the organs in place and storage of fats
D) Barrier to prevent the entry of pathogenic organisms
E) A cushioning to protect against injury from sports or car accidents

Answer 3

Ans: A, D
Feedback:
The first layer performs numerous functions. These include production of mucus that
lubricates and protects the inner surface of the alimentary canal; secretion of digestive
enzymes and substances that break down food; absorption of the breakdown products of
digestion; and maintenance of a barrier to prevent the entry of noxious substances and
pathogenic organism. The facilitation of movement of contents of the GI tract occurs in
the third layer while holding the organs in place, and storage of fats occurs in the fourth
layer.

Question 4

The instructor asks a group of nursing students to explain the function of the omentum.
The students will respond based on which pathophysiologic principle?
A) It holds organs in place.
B) It attaches the jejunum and ileum to the abdominal wall.
C) It has lots of mobility and moves around in the peritoneal cavity with peristaltic
movements.
D) It is mainly there to prevent any noxious substance from inner into the gut.

Answer 4

Ans: C
Feedback:
The greater omentum has considerable mobility and moves around in the peritoneal
cavity with the peristaltic movements of the intestines. It also cushions the abdominal
organs against injury and provides insulation against the loss of body heat. The
mesentery holds the organs in place and attaches the jejunum and ileum to the
abdominal wall. The mucosal layer acts as a barrier to prevent the entry of noxious
substances and pathogenic organisms.

Question 5

When the sympathetic nervous system is stimulated, the interstitial cells of Cajal,
pacemaker cells of the GI tract, react by
A) decreasing amplitude or abolishing the slow waves that control the spontaneous
oscillations in membrane potentials.
B) increasing the peristaltic motion of the GI tract, thereby causing explosive
diarrhea.
C) increasing the amount of secretions being entered into each segment of the
intestinal tract.
D) signaling the vagus nerve to slow down motility and increase absorption of water
from the large intestine.

Answer 5

Ans: A
Feedback:
The interstitial cells of Cajal that are found in groups between the layers of smooth
muscle tissue are hypothesized to function as the pacemakers. These cells display
rhythmic, spontaneous oscillations in the membrane potentials, called slow waves,
ranging in frequency from approximately 3 per minute in the stomach to 12 per minute
in the duodenum. The vagus nerve responds to parasympathetic innervation. GI motility
is enhanced because of increased vagal activity that could cause diarrhea.

Question 6

A gastroenterologist is teaching a group of medical students about the enteric nervous
system in preparation for a consult on client who has suffered a spinal cord injury.
Which of the physician’s teaching points is most accurate?
A) “The myenteric plexus is responsible for controlling the function of each segment
of the intestinal tract.”
B) “The enteric nervous system is made up of the myenteric and submucosal
plexuses; these are located in the wall of the GI tract.”
C) “Sympathetic innervation of much of the GI tract occurs by way of the vagus
nerve.”
D) “Parasympathetic stimulation blocks the release of the excitatory neuromediators
and inhibits GI motility.”

Answer 6

Ans: B
Feedback:
The enteric nervous system consists of the myenteric and submucosal plexuses, which
are located within the wall of the gastrointestinal tract. The myenteric plexus is
responsible for controlling overall function along the entire length of the gut, while the
vagus nerve provides parasympathetic, not sympathetic, innervation. Sympathetic
simulation lessens excitatory neuromediators and inhibits GI motility.

Question 7

A speech therapist is performing a swallowing assessment on a 72-year-old man who
has suffered a stroke 3 weeks ago. The man has been NPO (nothing by mouth) since his
stroke, and the health care team is considering the introduction of oral food. The speech
therapist is cueing the client to swallow to preclude either aspiration of food or
pocketing of food in the sides of his mouth. The client most likely to have conscious
control over which of the following processes listed below involved in swallowing?
A) Initiation of primary peristalsis
B) Moving the epiglottis back to cover the larynx
C) Moving a bolus to the posterior wall of the pharynx
D) Moving the bolus backward in the esophagus

Answer 7

Ans: C
Feedback:
Moving a bolus to the posterior wall of the pharynx is a component of the oral, or
voluntary, phase of swallowing. Initiation of primary peristalsis, moving the epiglottis
back to cover the larynx, and moving the bolus backward in the esophagus are all
involuntary components of the pharyngeal and esophageal phases of swallowing

Question 8

A male infant is brought into the clinic because of colic-like symptoms. The mother
states he acts like something is hurting. After eating, he vomits most of the feeding and
then assumes a fetal position. He is also not gaining weight. The nurse practitioner is
thinking that he is displaying clinical manifestations of obstruction and may have which
of the following medical diagnoses?
A) Duodenal ulceration
B) Constipation
C) Pyloric stenosis
D) Erosive esophagitis

Answer 8

Ans: C
Feedback:
An example of obstruction is hypertrophic pyloric stenosis, which can occur in infants
with an abnormally thick muscularis layer in the terminal pylorus. A defect in the lining
of the first part of the small intestine (duodenal ulcer) is usually caused by an infection
with a bacterium (germ) called H. pylori. When food is ingested and digested but not
excreted, it forms a blockage in the colon. Regular bowel movements are needed in
order for this not to occur. When bowel movements are irregular, constipation may
result. This infant appears to be vomiting his stomach content; therefore, no BM is
occurring since no food is being digested in the small intestine. Gastrin provides the
major stimulus for gastric acid production. Its action on the lower esophageal sphincter
protects the esophageal mucosa when gastric acid levels are elevated. If stomach acids
reflux into the esophagus, acid irritation and inflammation cause extensive injuries to
the esophagus.

Question 9

A 79-year-old male resident of a long-term care facility has contracted Clostridium
difficile and is experiencing consequent diarrhea. Auscultation of the man’s abdomen
indicates hyperactive bowel sounds. What process in the man’s small intestine is most
likely accompanying his current status?
A) Pathogenic microorganisms are causing dilation of his small intestine, increasing
motility.
B) Segmentation waves have become more frequent as a result of his infection.
C) Intestinal stasis brought on by infection is preventing his small intestine from
sufficiently slowing the rate of motility.
D) Inflammation is accompanied by an increase in peristaltic movements of his small
intestine.

Answer 9

Ans: D
Feedback:
Inflammation of the small intestine is accompanied by an increase in motility, an effect
that is the result of increased peristaltic waves. Segmentation waves are responsible
primarily for mixing rather than moving food. Neither dilation nor inadequate slowing
of passage contents is responsible for the increase in motility.

Question 10

Which of the following statements best communicates the nature of movements in the
colon?
A) The internal and external anal sphincters control the movement of feces into and
through the colon.
B) Haustrations move the colon contents along with 2- to 3-minute rest periods
between movements.
C) Segmentation waves ensure that all surfaces of the feces are exposed to the colon
surface.
D) Large segments of the colon contract as a unit for around 30 seconds.

Answer 10

Ans: D
Feedback:
The colon, unlike the small intestine, moves contents by the simultaneous contraction of
large segments. The anal sphincters control defecation rather than movements within the
colon, and haustrations perform mixing, not motility. Segmentation waves are present in
the small intestine.

Question 11

A 42-year-old female client with a long-standing history of chronic nausea and vomiting but a near-insatiable appetite has had her symptoms attributed to an enzyme deficiency. Further diagnostic testing indicates that she has inadequate pancreatic enzyme levels and that her large appetite is due to a lack of enzyme control of food intake inhibition. In which of the following enzymes is the woman most likely deficient?
A) Cholecystokinin
B) Ghrelin
C) Gastrin
D) Secretin

Answer 11

Ans: A
Feedback:
Cholecystokinin is responsible for inhibiting food intake as well as stimulating
pancreatic enzyme secretion. Ghrelin stimulates food intake, while gastrin stimulates
gastric acid production, and secretin inhibits it.

Question 12

A science teacher is talking to a group of fifth graders about the role of “spit.” During
the course of the discussion, the teacher asks the students which of the following are
functions of saliva?
A) Good protection device if someone is being attacked
B) Will have more saliva production when anxious, such as right before a test
C) Has antibacterial action to help keep the mouth clean
D) Secretes acid to chemically break down fatty foods like French fries
E) Secretes the enzyme pepsin

Answer 12

Ans: C
Feedback:
Saliva has three functions. The first is to protect and lubricate. The second is to provide
antimicrobial protection. The third is to initiate digestion of starches by secreting
enzymes. If anxious, SNS activity causes dry mouth. Saliva begins breaking down
starches (carbohydrates), not fatty foods. The chief cells secrete pepsinogen, which is
converted into pepsin, the enzyme that breaks down protein. This occurs in the stomach

Question 13

Which of the following medications used in the treatment of peptic ulcers and
gastroesophageal reflux binds to H2 receptors and blocks the action of histamine on
parietal cells?
A) Cimetidine (Tagamet)
B) Levbid (hyoscyamine)
C) Lotronex (alosetron)
D) Nexium (esomeprazole)

Answer 13

Ans: A
Feedback:
Cimetidine is a H2 receptor blocker used to treat peptic ulcers and GERD. It binds to H2
receptors and blocks the action of histamine on parietal cells. Levbid and Lotronex are
anticholinergics, while Nexium is a proton pump inhibitor that inhibits gastric acid
secretion.

Question 14

A 77-year-old woman has been admitted to hospital following several weeks of
increasing fatigue. On observation, she is pale, and blood work indicates she has low
hemoglobin and red cell counts. Stool tests for occult blood are positive, and following
endoscopy, she has been diagnosed with an upper GI bleed that has been shown to
originate in her stomach. She admits to regularly exceeding the recommended doses of
nonsteroidal anti-inflammatory drugs (NSAIDs) in an effort to control her rheumatoid
arthritis. Which of the following phenomena is most likely responsible for her present
health problems?
A) NSAIDs increase the gastric production of gastrin, increasing gastric secretions
and lowering stomach pH.
B) Drugs such as NSAIDs increase the H+ levels and thus decrease gastric pH,
resulting in insult to the stomach lining.
C) NSAIDs, aspirin, and other drugs increase prostaglandin synthesis, resulting in
disruption of cellular structures lining the stomach.
D) NSAIDs can disrupt the permeability of the gastric mucosa, causing hydrogen
ions to accumulate in the mucosal cells of the lining.

Answer 14

Ans: D
Feedback:
NSAIDs damage the mucosal barrier, allowing hydrogen ions to damage cells of the
stomach lining. They do not directly increase gastrin production or H+ levels, and
decreased, not increased, prostaglandin synthesis would potentially compromise the
gastric surfaces.

Question 15

Chronic anxiety and stress contribute to ulcers. Which of the following effects of the
sympathetic nervous system is most responsible for this effect?
A) Inhibition of the actions of Brunner glands
B) Overstimulation of the oxyntic glands
C) Suppression of cholecystokinin
D) Inflammation of the parotid glands

Answer 15

Ans: A
Feedback:
Brunner glands, which produce large amounts of alkaline mucus that protects the
duodenum from acid and digestive enzymes, are strongly affected by sympathetic
stimulation, which causes a marked decrease in mucus production. Where the stomach
contents and secretions from the liver and pancreas enter the duodenum, deficiency of
mucus can cause irritation and, potentially, ulcers. Overstimulation of the oxyntic glands
is not produced by the SNS. The hormone cholecystokinin, which is thought in part to
control gastric emptying, is released in response to the pH, osmolality, and fatty acid
composition of the chyme. The two largest salivary glands are called parotid glands.
One is located in each cheek over the jaw in front of the ears. Inflammation of one or
more of these glands is called parotitis.

Question 16

Following a 14-day course of broad-spectrum antibiotics for the treatment of sepsis, a
60-year-old woman has developed watery diarrhea. Her care team attributes this to
likely elimination of normal intestinal flora by the antibiotics. What other phenomena is
most likely accompanying her low levels of normal flora?
A) Decreased mineral and nutrient absorption; decreased carbohydrate metabolism
B) Decreased pH of the stomach; increased pH of the lower GI tract
C) Decreased fermentation of undigestible dietary residue; decreased vitamin
absorption
D) Proliferation of vitamin K; lower GI bleeding

Answer 16

Ans: C
Feedback:
Central among the functions of normal intestinal flora are the fermentation of dietary
components that are not digestible and the facilitation of vitamin absorption. Mineral
and nutrient absorption as well as carbohydrate metabolism are less likely to be affected,
while vitamin K production would likely decrease somewhat. pH is unlikely to be
affected.

Question 17

A patient has just been diagnosed with pernicious anemia. The patient asks the nurse
why his body is not able to absorb vitamin B12. The nurse responds,
A) “You have too many ulcers in your stomach.”
B) “More than likely, you were born with deficient vitamin B12 stores.”
C) “Your stomach is not secreting a substance known as intrinsic factor, which is
needed to absorb vitamin B12.”
D) “Your daily intake of high saturated fats is interfering with the stomach’s ability to
absorb the nutrients that it needs, especially vitamin B12.”

Answer 17

Ans: C
Feedback:
Vitamin B12 is not absorbed in the absence of intrinsic factor, which is secreted by the
parietal cells of the stomach. Ulcers in the stomach do not cause pernicious anemia. This
is not a congenital problem, nor does the intake of fats interfere with the secretion of
intrinsic factor.

Question 18

A male client complaining of chronic cramping, bloating, and diarrhea has been
determined to have a deficiency in brush border enzymes within his small intestine.
Which of the following meals or snacks high in carbohydrates and protein will likely
exacerbate the client’s signs and symptoms?
A) Grapefruit and prunes
B) Tossed salad with an oil and vinegar dressing
C) Roast beef and a baked potato
D) Tortilla chips and guacamole

Answer 18

Ans: C
Feedback:
Brush border enzymes are primarily responsible for the metabolism of carbohydrates
and proteins, substances best exemplified by a baked potato and roast beef, respectively.
Of the distracters, choice C has both high protein and high carbohydrate content.
Distracters A, B, and D are not high in both carbohydrates and proteins.

Question 19

A mom asks her neighbor, a nurse, why every time she takes her daughter (10 years old)
out for ice cream she comes home with a stomachache and then experiences a bout of
diarrhea. The nurse is thinking that this girl is experiencing
A) anxiety about increasing too many calories.
B) a deficiency of lactase.
C) gallbladder disease.
D) premature peptic ulcer formation.

Answer 19

Ans: B
Feedback:
People with a deficiency of lactase, the enzyme that breaks down lactose, experience
diarrhea when they drink milk or eat dairy products. Doubtful the child is anxious about
the calories in ice cream. Gallbladder disease s/s usually occur in relation to high
saturated fat intake. Peptic ulcer s/s include bloating, vomiting blood, foul coffee ground
stools, etc.

Question 20

Which of the following statements best captures an aspect of the process of fat digestion
and absorption?
A) Ingested triglycerides are broken down into absorbable form by gastric lipase.
B) Triglycerides are digested with the aid of bile salts.
C) Long-chain fatty acids are absorbed directly into the portal blood.
D) Stool is not excreted until all fat is absorbed.

Answer 20

Ans: B
Feedback:
After breakdown, by pancreatic lipase, triglycerides are absorbed primarily in the upper
jejunum. Long-chain fatty acids are absorbed less easily than medium-chain
triglycerides, while stool often contains a certain amount of fat.