GI tract Flashcards
Function of the gut
digestion and absorption
What propels food through the gut
peristalsis - muscular contraction
What does the stomach lining produce
acid and pepsin (breaks down protein)
Where does most of the digestion occur
duodenum
What does the pancreas release in the duodenum
digestive enzymes
What does the liver release into the duodenum and what is it good for?
Bile produced by the liver is also released into the duodenum, and is important in the absorption of fat.
What is the entire small bowel important in
absorption of digested food
The role of the large bowel
absorb water and electrolytes, producing formed stools
General signs and symptoms of diseases of the gut
Diseases of the gut may be silent (asymptomatic) or produce the following signs and symptoms: loss
of appetite, nausea, vomiting, diarrhea, pain, bleeding, obstruction.
What is hematenesis
vomiting of blood
if the bleeding is from the stomach or duodenum, what color is the stool? why?
black (melena) because of the action of acid and digestive enzymes on the blood.
What happened if stool is red colored
Bleeding from the rest of the small and large bowel (hematochezia)
When is bleeding said to be occult?
if the amount is too small to be seen with the naked eye, but can still be detected by a chemical test for blood.
Cancer of the _____ account for 6% of GI tract cancers
esophagus
About ___% of esophageal cancers are adenocarcinomas and ___% squamous cell carcinomas. Who is incidence highest in?
60, 40 - males >50 y.o
How do Adenocarcinoma and squamous cell carcinoma of the esophagus differ? What do these patients usually present with
In pathogenesis –> dysphagia
Longstanding gastroesophageal reflux may result in the following sequence of events in the lower esophagus:
intestinal metaplasia (known as Barrett esophagus) –> dysplasia –> adenocarcinoma.
The major risk factors for squamous cell carcinoma in Canada are…
alcohol and tabacco
How can Esophageal tumors cause harm and how do they spread
Esophageal tumors can cause harm by local obstruction and spread due to the proximity to several important structures, e.g. the trachea, the large vessels of the heart.
What is the problem with symptoms associated with esophageal tumors
Unfortunately, by the time that the tumor causes symptoms, it is often not curable by surgery due to invasion through the wall of the esophagus and spread to lymph nodes.
What is Adenocarcinoma 5 year survival rate
5-10%
What is a peptic ulcer
a break in the mucosal lining of the gastrointestinal tract produced by the action of gastric secretions (i.e. acid and pepsin).
what is the structure of a normal mucosa
an impermeable epithelial cell covering and layer of mucus.
When do peptic ulcers result
when the mucosa is damaged, leaving it susceptible to breakdown by gastric acid and pepsin.
Where are most peptic ulcers
stomach and duodenum
What % of the population is affected by peptic ulcers
10%
Which is more common, duodenal ulcers or gastric ulcers
Duodenal ulcers are 4 times more common than gastric ulcers
What age are duodenal and gastric ulcers most common
most frequent around age 20 and gastric ulcers around age 40
What sex is more likely to get duodenal ad gastric ulcers
duodenal - male
gastric - equal
Two main causes for peptic ulcers
Helicobacter pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ASA and ibuprofen.
HP is the cause of ___% of gastric ulcers and ___% of duodenal ulcers
80 90
What is HP? it is found in the stomach of ___% of people
a bacteria, 20% of people under 40 y.o 50% over the age 50
What do we know about how one acquires HP? Where has HP been identified in?
The infection is usually acquired in early childhood by transmission from mother to child, and the bacteria may remain in the stomach for the rest of the person’s life. HP has been identified in saliva, feces, and vomitus.
What does HP always result in? Will it always eventually result in an ulcer?
Although HP infection always results in inflammation of the stomach lining, most people are asymptomatic and only 10-15% will develop an ulcer at some time
during their life.
What is it thought that ulceration is due to?
It is thought that ulceration is due to increased gastric acid production
what determines the outcome of the infection
The strain of the organism and a variety of host factors determine the outcome of the infection
how can HP infections be diagnosed
HP infection can be diagnosed by antibody tests, by identifying the organism in endoscopic biopsies, or by a noninvasive breath test that identifies bacterial production of an enzyme in the stomach.
Of the gastric and duodenal ulcers not caused
by HP infection, most are due to _______ which block ______________ __________. What are important in maintaining an intact mucosal barrier
NSAIDs which block prostaglandin synthesis
Prostaglandins produced by the gastric mucosa are important in maintaining an intact mucosal barrier
most common symptom of peptic ulcers
upper abdominal pain, although a significant number, especially the elderly, are asymptomatic.
how can peptic ulcers be ruled out as cancer
biopsy
complications of peptic ulcers
treatment of peptic ulcers
bleeding (occult or massive and life threatening), obstruction due to formation of scar tissue, and perforation with peritonitis.
Medical treatment includes antacids and drugs inhibiting acid secretion, and antibiotics to eradicate Helicobacter pylori (if present). Surgery is performed when drug therapy fails, or to treat complications.
lifetime risk of appendicitis (%)
10%
what is the most common acute abdominal condition needing surgery
appendicitis
In 50-80% of cases of acute appendicitis, the _______ is obstructed, usually by a _______ (hard piece of stool)
lumen, fecalith
once the lumen is obstructed in acute appendicitis, what happens next
Mucus continues to be produced in the obstructed appendix, leading to an increase in intraluminal pressure, compression of veins, and ischemic injury. Bacterial proliferation in the presence of obstruction and ischemia increases the inflammatory reaction. In the cases without obstruction, the etiology/ pathogenesis is unknown
