Fundamentals of Anatomy and Physiology

Nutrition and the Digestive System 397

Common Disease, Disorder, or Condition

Disorders of The Digestive System continued

or incompetency of the lower esophageal sphincter. Since the gastric juice is high in

hydrochloric acid, this causes a burning sensation in the esophagus, commonly re-

ferred to as “heartburn.” Consistent episodes of GERD may lead to severe damage to

the esophageal lining. Preventative measures include sleeping with two pillows to

elevate the head, drinking a glass of water before retiring, avoiding highly acidic foods

at evening meals, and the use of antacids like TUMS.

Gastric Cancer^
Gastric or stomach cancer produces gastric tumors called adenocarcinomas. The
exact cause is unknown. However, dietary factors that have been implicated include ni-
trates as preservatives in foods, smoked or salted meats and fish, and the inges-tion of
moldy foods. Infection with the bacterium Helicobacter pylori has also been implicated.
Symptoms include chronic discomfort, a loss of appetite with develop-ing anorexia,
difficulty eating, weight loss, and developing anemia. Yearly medical examinations
usually include a test for occult blood in the stool to check for early signs of cancer in
the digestive system. Other diagnoses include an upper GI series and an endoscopy.
Individuals exposed to excessive chemicals like asbestos or living in a highly polluted
industrialized area can also develop stomach or gastric cancer. Surgery is usually
recommended for removal of the tumors.

Pancreatic Cancer^
Pancreatic cancer is an uncommon but deadly cancer. Individuals diagnosed with the
disease rarely live for more than 1 year. It occurs more often in men than in women
(three to four times more often in men). It occurs more often in industrialized areas,
among smokers, people with diabetes, and individuals exposed to polychlorinated
biphenyl compounds. Symptoms include weakness, weight loss, jaundice, gas, epi-
gastric pain, and an onset of diabetes. Occasionally, localized tumors may be re-moved
surgically by a partial pancreatectomy and removal of part of the stomach, the
duodenum, and common bile duct.

Oral Cancer^
Oral cancer is a malignancy found either in the mouth or on the lips that can occur after
age 60. It occurs more frequently in men than women. Contributing factors include
smoking, the use of chewing tobacco, poor oral hygiene, alcoholism, and even poor-
fitting dentures. Pipe smoking contributes to the development of lip can-cer as does
overexposure to the wind and sun. Usually a painless, nonhealing ulcer is the first sign
of the cancer. Frequent dental checkups can detect the development of oral cancer of
which only 5% are fatal.

decomposition, such as gas and odor (hydrogen sulfide gas,
H 2 S, which produces a “rotten egg” odor), and un-digested
parts of food not attacked by bacteria are also found in the
feces. The more fiber (the cellulose of plant cell walls from
eating fruits and vegetables) in the diet, the more
undigestible materials in the feces and the softer the stool.

When mass peristalsis pushes the fecal material into

the rectum, it causes distention of the rectal walls. This

triggers pressure-sensitive receptors in the walls of the

rectum, sending an impulse to the nervous system, which

initiates the reflex for defecation. Defecation is the act of

emptying the rectum and is the final activity of the

digestive system.