GI tract Flashcards
how can ulcers be visualized?
by gastroscopy
what is achalasia?
inability of lower esophageal sphincter to relax causing fluid build up in esophageus
what is a solution for achalasia? however what can it cause
insertion of balloon that keep LES open. can lead to heartburn
what can cause esophageal varices?
liver diseases like alcoholic liver disease or cirrhosis
what is the risk of esophageal varices?
they can rupture and cause hemorrhage
what is heartburn
gastroesophageal reflux disease GERD: reflux of gastric acid from stomach to esophagus causing burning sensation
what pressures act on LES to keep it closed?
intraabdominal pressure
what increase risk of heart burns?
obesity, pregnancy: cause higher intragastric pressure
what is hiatus hernia?
part of stomach moves over the diaphragm through the hiatus
symptoms of hiatus hernia
pain, hyperplasia, ulceration, fibrosis, structure, dysphagia, spasm, metaplasia
GERD risk factors?
hiatus hernia, obesity, pregnancy, alcohol, cigarettes
Gerd can cause what other health issue?
squamous cell carcinoma
what can increase reflux?
obesity, smoking, coffee, high sugar, eating before bed
what is gastritis?
Inflammation in the wall of the stomach that causes pain and loss of sensory nerve endings.
what substances can damage the stomach and cause gastritis?
ethanol (alcohol), NSAIDs, other drugs, food poisoning
what cells are in the gastric epithelium of gastric mucosa and where?
mucous cells at the surface
parietal cell a little lower
chief cell lower
enteroendocrine cells at the very bottom
what do the mucous cells do?
produce mucous that keeps acid from reaching to cells lower in the villi (parietal, chief, enteroendocrine cells)
what are the stomach epithelium defensive forces?
surface mucus secretion,
bicarbonate in mucus,
mucosal blood flow,
apical surface membrane transport,
epithelial regeneration,
what do the stomach epithelium defensive forces do?
destroy microorganisms in food for digestion.
complications (?) of gastritis
damage -> ulceration
what promotes gastritis?
smoking: it also impairs healing.
too much aspirin.
where can ulcers appear?
in all of the stomach, even esophagus and duodenum
who had ulcers lol?
napoleon
what do ulcers start as?
erosion of gastric mucosa
how can ulcers kill you?
is the ulcer gets all the way to the serosa (perforation)
what causes peptic ulcers?
imbalance between acid output and mucosal defense
what are the dangers of duodenal ulcers?
hemorrhage, perforation, stricture (narrowing)
who is more affected by duodenal ulcers?
appears at a younger age and more common in males
what causes peptic ulcers?
imbalance between acid output and mucosal defense.
same molecules as gastric ulcers (ethanol, NSAIDs, …)
what can reduce secretion of gastric acid? how?
acid pump inhibitors, histamine blockers, antiacid; decrease acidic output
what was the problem with antacids? what caused that?
when patient stops taking it, the ulcers come back because of bacteria name name in the stomach
how does the bacteria H. pylori affect GI tract?
it survives in stomach acid and literally digs holes in stomach and mucosal cells.
it secretes effectors and enzime that neutralize hydrochloric acid.
it can also attach itself to target cells
4 or 3 things that the bacteria can secrete
ammonia: neutralize acid
urease: injure mucosal cell
exotoxin vacA: mucosal injury
enzymes: protease, lipase, mucinase
how does the bacteria trigger the immune system?
recruitment of macrophages.
causes chronic inflammation.
where does food spend the much time?
intestine
what can cause mechanical intestinal obstruction?
tumor, cancer medication, opioids
what is volvulus?
part of intestine rotates and blocks itself off. secretion still going on, absorption stopped
what is intussusception?
intestine folds/slips onto itself and causes a blockage and pain. can require surgery.
what is paralytic ileus?
involves the enteric nervous system. often caused by surgery upsetting neurons, causing a cessation of movement
what cells are involved in paralytic ileus?
resident macrophages, neurons, smooth muscle cells
oh to deal with obstructive diseases?
what is diverticulosis? what causes it?
side effect of low fiber diet: protrusion of intestine (diverticula)
diverticulosis complications
- can rupture
- can cause bleeding due to vessel injury
- can cause abscess in intestine wall
- fistula: communication between organs
- impacted fecalith
what is celiac disease?
can’t digest wheat/gluten -> creates peptides that gets in intestinal wall and damages epithelial cells
(cytokines are also involved)
what kind of disease is celiac?
autoimmune T-cell mediated enteropathy
what are genes associated with celiac disease?
MHC II gene HLA-DQ2/8.
how do you diagnose celiac disease?
intestinal biopsy + antibodies (IgA anti-TG2)
more ab celiac
what are the 2 variants of IBD?
crohn’s disease (injured regions can be all over the intestine - skip lesion)
ulcerative colitis (in the colon only - continual lesion)
what does corhn’s disease cause?
transmural lesions, skip lesions, damage to epithelial cells and microvilli, pain, bleeding, can cause fistula, strictures, scarring
ulcerative collitis.
what is axute apendicitis?
blockage of apendice, usually by fecalist, causing infection and inflammation
what can happens if appendicitis is not diagnosed soon enough?
necrosis
where is the appendice?
it can have different locations
where do you feel the pain of appendicitis?
at first in the middle of abdomen, then right bottom abdomen once it gets more serious
how much fluid are we secreting every day? how much does the colon absorbs a day?
Secretes 9L of fluid in the intestine
Colon absorbs 8.9L
who is diarrhea dangerous for?
young children because their absorption system is not good yet
what is secretory diarrhea? osmotic?
secretory = too much fluid secreted in the gut
osmotic = osmotic retention of fluid because can’t digest lactose
causes of diarrhea?
consequences of diarrhea?
what is cholera? where is it most present?
old microbe from contaminated water.
Haiti
describe cholera toxin
toxin produced by microbe that inserts in cell membrane and turns on G proteins causing continuous chloride secretion
treatment for cholera
oral rehydration therapy. there is also a vaccine available
what is rotavirus?
global virus that kills children in poor countries. virus survives on objects for days
what does roatvirus damage?
damages enterocytes (decrease absorption) and something else
why is rotavirus so dangerous?
it has a counter-attack for each defense mechanisms of the body.
is there treatment against rotavirus?
there is an effective vaccine!
what is the biggest cause of food poisoning?
norovirus
what causes 20% of gastroenteritis?
norovirus
norovirus symptoms
nausea, vomiting, pain, …
is there a treatment for norovirus?
info missed
how does norovirus gets transmitted?
what does norovirus do to cells?
damages epithelial GI cells: flattened the microvili
what is salmonella?
type of food poisoning. bacteria crosses intestinal barrier into submucosa and survives macrophages
how does salmonella get through intestinal barrier?
injects proteins in epithelial cells
what is crazy about staphylocci?
symptoms onset after 1h of infection because the toxin is already formed in the food and stays stable in heat
what are the different types of e. coli and what do they cause?
4 types
what is the toxin produced by E. coli thats dangerous?
shiga toxin. from E. 0157:H7
symptoms of E. coli shiga toxin?
nausea, …
