N5315 Advanced Pathophysiology
Gastrointestinal
Core Concepts and Objectives with Advanced Organizers
GI System Anatomy and Physiology
Examine the anatomy and physiology of the GI system:
1. Differentiate between the organs which make up the upper gastrointestinal track and the lower
gastrointestinal track.
Upper: mouth, esophagus, stomach, duodenum
Lower: rest of small intestine (jejunum and ileum), large intestine, anus
2. Explain the hepatoportal circulation anatomy and physiology. WATCH KAHN ACADEMY
3. Discuss the effects of aging on the gastrointestinal tract.
The changes in the GI system that are associated with aging are dependent
upon a person’s health status, genetics, and environmental factors. Some
changes can begin before the age of 50. As we age, we lose tooth enamel
and dentin, which increases the risk for developing cavities. Periodontal
disease, gum recession and osteoporosis can cause one to lose teeth. The
sense of smell decreases as does the ability to taste secondary to a loss of
taste buds. This leads to a reduced appetite in the elderly. Esophageal
motility decreases with age and may lead to GERD. Gastric motility, gastric
secretions and blood flow decreases with age which leads to an increased risk
of injury to the mucosal lining. A decreased production in intrinsic factor is
also noted as we age which may lead to B12 deficiency and pernicious
anemia. Ileal villi become broader and shorter. Degeneration of the enteric
nervous system neurons decreases intestinal absorption, motility, blood flow
and impairs nutrient absorption. Nutrients are absorbed more slowly and in
lesser amounts.
The liver is not able to regenerate as fast in the elderly. Hepatic blood flow
decreases with age as does the enzymatic activity both of which decreases
drug metabolism. LFTs remain normal in the elderly and an elevation is a sign
of a disorder and not a result of aging. The pancreas experiences some age-
related fibrosis, fatty acid deposits and atrophy. The beta cells’ function
declines as well as we age.
Examine the pathologic basis of adult and pediatric disorders which affect the GI
system:
Gastrointestinal Bleeds
,4. Analyze the etiologies and pathophysiology of osmotic, secretory, and motility related
diarrhea.
Type of Diarrhea Etiology Pathophysiology
Osmotic presence of a
nonabsorbable substance pulls water by osmosis
in the intestines. into the intestinal lumen
causes include tube and results in large
feedings, dumping volume diarrhea. This is
syndrome, malabsorption, how the laxatives mag
pancreatic enzyme citrate, lactulose and
deficiency, bile salt MiraLAX work. Excessive
deficiency, small intestine ingestion of
bacterial overgrowth, or nonabsorbable sugars
celiac disease. can cause this type of
diarrhea.
Secretory These infections trigger
large volume losses enteroendocrine cells to
secondary to infectious secrete 5HT and the
causes such as the activation of afferent
rotavirus, bacterial neurons that stimulate
enterotoxins, or C-diff. submucosal secretomotor
neurons and alter sodium
chloride transport
resulting in decreased
water absorption.
Motility Complications of diarrhea
AKA as short bowel may include dehydration,
syndrome and results electrolyte imbalances,
from the resection of the metabolic acidosis,
small intestine or a weight loss, and
surgical bypass of the malabsorption. Fatty
small intestine or a stools are common in
portion of it, IBS, diabetic malabsorption syndromes
neuropathy, as is bloating. Most
hyperthyroidism, and infectious diarrhea
laxative abuse. usually lasts less than 2
weeks. Fever, cramping
and bloody stools may be
seen in chronic diarrhea
and are caused by
inflammatory bowel
disease or dysentery.
5. Analyze the etiology, clinical manifestations, and pathophysiology of the upper and lower GI
bleed.
Disease Etiology Clinical Manifestations Pathophysiology
, Upper GI Bleed
any source Hematemesis: bright
of bleeding red, bloody emesis;
which emergent
occurs in intervention
the
esophagus, Coffee ground
stomach or emesis
the
duodenum. Melena: stool is
It is black and tarry.
characteriz
ed by
frank,
bright red
or “coffee
ground”
(affected
by the
stomach)
emesis. It
is
commonly
caused by
bleeding
varices
(varicose
veins) in
the
esophagus
or
stomach,
peptic
ulcers,
gastritis, or
a Mallory-
Weiss tear
(tearing of
the
esophagus
from the
stomach
Lower GI Bleed
characteriz Hematochezia is the
ed by any presence of bright
source of red blood in the
bleeding in stools and the
the presence of
jejunum, hematochezia
ileum, suggests that the
Gastrointestinal
Core Concepts and Objectives with Advanced Organizers
GI System Anatomy and Physiology
Examine the anatomy and physiology of the GI system:
1. Differentiate between the organs which make up the upper gastrointestinal track and the lower
gastrointestinal track.
Upper: mouth, esophagus, stomach, duodenum
Lower: rest of small intestine (jejunum and ileum), large intestine, anus
2. Explain the hepatoportal circulation anatomy and physiology. WATCH KAHN ACADEMY
3. Discuss the effects of aging on the gastrointestinal tract.
The changes in the GI system that are associated with aging are dependent
upon a person’s health status, genetics, and environmental factors. Some
changes can begin before the age of 50. As we age, we lose tooth enamel
and dentin, which increases the risk for developing cavities. Periodontal
disease, gum recession and osteoporosis can cause one to lose teeth. The
sense of smell decreases as does the ability to taste secondary to a loss of
taste buds. This leads to a reduced appetite in the elderly. Esophageal
motility decreases with age and may lead to GERD. Gastric motility, gastric
secretions and blood flow decreases with age which leads to an increased risk
of injury to the mucosal lining. A decreased production in intrinsic factor is
also noted as we age which may lead to B12 deficiency and pernicious
anemia. Ileal villi become broader and shorter. Degeneration of the enteric
nervous system neurons decreases intestinal absorption, motility, blood flow
and impairs nutrient absorption. Nutrients are absorbed more slowly and in
lesser amounts.
The liver is not able to regenerate as fast in the elderly. Hepatic blood flow
decreases with age as does the enzymatic activity both of which decreases
drug metabolism. LFTs remain normal in the elderly and an elevation is a sign
of a disorder and not a result of aging. The pancreas experiences some age-
related fibrosis, fatty acid deposits and atrophy. The beta cells’ function
declines as well as we age.
Examine the pathologic basis of adult and pediatric disorders which affect the GI
system:
Gastrointestinal Bleeds
,4. Analyze the etiologies and pathophysiology of osmotic, secretory, and motility related
diarrhea.
Type of Diarrhea Etiology Pathophysiology
Osmotic presence of a
nonabsorbable substance pulls water by osmosis
in the intestines. into the intestinal lumen
causes include tube and results in large
feedings, dumping volume diarrhea. This is
syndrome, malabsorption, how the laxatives mag
pancreatic enzyme citrate, lactulose and
deficiency, bile salt MiraLAX work. Excessive
deficiency, small intestine ingestion of
bacterial overgrowth, or nonabsorbable sugars
celiac disease. can cause this type of
diarrhea.
Secretory These infections trigger
large volume losses enteroendocrine cells to
secondary to infectious secrete 5HT and the
causes such as the activation of afferent
rotavirus, bacterial neurons that stimulate
enterotoxins, or C-diff. submucosal secretomotor
neurons and alter sodium
chloride transport
resulting in decreased
water absorption.
Motility Complications of diarrhea
AKA as short bowel may include dehydration,
syndrome and results electrolyte imbalances,
from the resection of the metabolic acidosis,
small intestine or a weight loss, and
surgical bypass of the malabsorption. Fatty
small intestine or a stools are common in
portion of it, IBS, diabetic malabsorption syndromes
neuropathy, as is bloating. Most
hyperthyroidism, and infectious diarrhea
laxative abuse. usually lasts less than 2
weeks. Fever, cramping
and bloody stools may be
seen in chronic diarrhea
and are caused by
inflammatory bowel
disease or dysentery.
5. Analyze the etiology, clinical manifestations, and pathophysiology of the upper and lower GI
bleed.
Disease Etiology Clinical Manifestations Pathophysiology
, Upper GI Bleed
any source Hematemesis: bright
of bleeding red, bloody emesis;
which emergent
occurs in intervention
the
esophagus, Coffee ground
stomach or emesis
the
duodenum. Melena: stool is
It is black and tarry.
characteriz
ed by
frank,
bright red
or “coffee
ground”
(affected
by the
stomach)
emesis. It
is
commonly
caused by
bleeding
varices
(varicose
veins) in
the
esophagus
or
stomach,
peptic
ulcers,
gastritis, or
a Mallory-
Weiss tear
(tearing of
the
esophagus
from the
stomach
Lower GI Bleed
characteriz Hematochezia is the
ed by any presence of bright
source of red blood in the
bleeding in stools and the
the presence of
jejunum, hematochezia
ileum, suggests that the
