Maintenance of the Body
Name one inﬂammatory condition of the digestive system
particularly common to adolescents, two common in middle age,
and one common in old age.
What are the eﬀects of aging on digestive system activity?
and Clinical Application
You are a research assistant at a pharmaceutical company. Your
group has been asked to develop an eﬀective laxative that
(1) provides bulk and (2) is nonirritating to the intestinal mucosa.
Explain why these requests are important by describing what
would happen if the opposite conditions were present.
AFer a heavy meal rich with fried foods, Debby Collins, an
overweight 45-year-old woman, was rushed to the emergency room
with severe spasmodic pains in her epigastric region that radiated to
the right side of her rib cage. She indicated that the attack came on
suddenly, and her abdomen was found to be tender to the touch and
somewhat rigid. What do you think is this patient’s problem and why
is her pain discontinuous (colicky)? What are the treatment options
and what might happen if the problem is not resolved?
A baby is admitted to the hospital with a history of diarrhea
and watery feces occurring over the last three days. Te baby
has sunken fontanelles, indicating extreme dehydration. ±ests
indicate that the baby has a bacterium-induced colitis, and
antibiotics are prescribed. Because of the baby’s loss of intestinal
juices, do you think that his blood pH would indicate acidosis or
alkalosis? Explain your reasoning.
Gary ²rancis, a middle-aged salesman, complains of a burning
pain in the “pit of his stomach,” usually beginning about two
hours aFer eating and abating aFer drinking a glass of milk.
When asked to indicate the site, he points to his epigastric region.
Te GI tract is examined by X-ray ﬂuoroscopy. A gastric ulcer is
visualized, and drug therapy using an antibiotic-bismuth approach
is recommended. (a) Why is this treatment suggested? (b) What are
the possible consequences of nontreatment?
Dr. Dolan used an endoscope to view Mr. Habib’s colon. He noted
the presence of several polyps and removed them during the
same procedure. What is an endoscope? Why did Dr. Dolan opt
to remove the polyps immediately?
Mr. Holden has had severe diarrhea all day and is severely weakened.
Explain why his nurse is concerned about his present condition.
What is the protective value of having several sets of tonsils at the
oral entry to the pharynx?
Before the blood carrying the products of protein digestion
reaches the heart, it ﬁrst passes through capillary networks in
Having passed through the regulatory organ selected above, the
products of protein digestion are circulated throughout the body.
Tey will enter individual body cells by
Short Answer Essay Questions
Make a simple line drawing of the organs of the alimentary
canal and label each organ. Ten add three labels to your
drawing—salivary glands, liver, and pancreas—and use arrows to
show where each of these organs empties its secretions into the
Sara was on a diet but she could not eat less and kept claiming her
stomach had a mind of its own. She was joking, but indeed, there
is a “gut brain” called the enteric nervous system. Is it part of the
parasympathetic and sympathetic nervous system? Explain.
Name the layers of the alimentary canal wall. Note the tissue
composition and major function of each layer.
What is a mesentery? Mesocolon? Greater omentum?
Name the six functional activities of the digestive system.
(a) Describe the boundaries of the oral cavity. (b) Why do you
suppose its mucosa is stratiﬁed squamous epithelium rather than
the more typical simple columnar epithelium?
(a) What is the normal number of permanent teeth? Of
deciduous teeth? (b) What substance covers the tooth crown? Its
root? (c) What substance makes up the bulk of a tooth? (d) What
and where is pulp?
Describe the two phases of swallowing, noting the organs
involved and the activities that occur.
Describe the role of these cells found in gastric glands: parietal,
chief, mucous neck, and enteroendocrine.
Describe the regulation of the cephalic, gastric, and intestinal
phases of gastric secretion.
(a) What is the relationship between the cystic, common hepatic,
bile, and pancreatic ducts? (b) What is the point of fusion of the
bile and pancreatic ducts called?
Explain why fatty stools result from the absence of bile or
Indicate the function of the stellate macrophages and the
hepatocytes of the liver.
What are (a) brush border enzymes? (b) chylomicrons?
Activation of pancreatic enzymes in the small intestine is a good
example of the wisdom of the body. How so?
Related Clinical Terms
A disorder in which swallowing is hindered or prevented.
Botox injections can relax the esophageal sphincter.
bag, bladder) Abnormal accumulation of
ﬂuid within the peritoneal cavity; if excessive, causes visible
bloating of the abdomen. May result from portal hypertension
caused by liver cirrhosis or by heart or kidney disease.
A pathological change in the epithelium
of the lower esophagus from stratiﬁed squamous to a
columnar epithelium. A possible sequel to untreated chronic
gastroesophageal reﬂux due to hiatal hernia, it predisposes the
individual to aggressive esophageal cancer (adenocarcinoma).
sizm) Grinding or clenching of teeth, usually at
night during sleep in response to stress. Can wear down and
crack the teeth.
behavior—episodes of massive overeating followed by some
method of purging (self-induced vomiting, taking laxatives or
diuretics, or excessive exercise). Most common in women of high
school or college age and in high school males in certain athletic
activities (wrestling). Rooted in a pathological fear of being fat,
and a need for control; provides a means of handling stress and
depression. Consequences include eroded tooth enamel, stomach
AT T H E C L I N I C