gi tract Flashcards
4 major functions…
motility, secretion, digestion, absorption
length of the digestive tract:
8-10 m
most of the absorption occurss in the_____ ______
small intestine
absorption in sm intestines depends on
transport proteins, secondary MonoSS, AA, Purines/pyrimides, surface area, bile emulsifiers, chylomicrons support of lipids
motility
muscle movements that support digestive activities
peristalisis
wave motions in the sm intestine that allow food movment to the next segement
migrating myoelectric complex:
current that depolarizes smooth muscle cells
segementations:
process that occurs in the small in testine that breaks down food bolus into much smaller particles
endocrine hormones
gastrin, gherlin, cholecystokinin
exocrine:
enzmyes, bile, gastric juices, pancreatic juces (bicarb, bile salts from gallbladder
cephalic phase
smells food sitms the stomach to produce gastric juices
gastric phase
Proteins: AA in stomach stims the receptors to further promote local secretion of gastrin, gastric juces/motility enteric nervous system
interstitial phase
as chyme reaches sm intestine chem receptors stim SI to release hormones that decrease stomach stomach motility+
protiens involved in digestion
trypsin, chymotrypsin, brush border peptidases
carbs involved in digestion
poly ss, bursh border ss
nucleic acids involved in digestion
nucleases, bursh boarder
lipids
bile/salts/lecithin, brush border
how can lipids be broken down?
simple diffusion, exocrine enterokinase will convert typsinogen into tyrpsin ( active form), endocrine: cholecystokinin ( decreases gastric juces & promotes breakdown), secretin: occurs when Hcl & lipids enter the duodenum–> decreases gastric juices
potential pacemaker of bowels…..
segmentation
accessory organs
liver (bile salts), pancreas(exocine: pancreatic jucies secreted through the pancreatic duct–> common bile duct–> secretes in the duodenum via sphincter of Oddi, endocrine: primary secretion are insulin & glucagon
pancreatic secretions:
HCO3—+ph in duodenum (secretion stimmed by secretin)
Trypsinogen
Chymotrypsin
Amylase
Lipase
nuclease(secretion stim by cholecystokinin (CCK)
Hiatal hernia
When part of the stomach passes through the diaphragm into the chest cavity
Pregnancy, hort esophagus, weak diaphragm
Patho:
Sliding→ esophagus & stomach move together
Paraesophageal ( rolling)- fundus moves through the diaphragm( can become tangled)–> ischemic
Clinical manifestations:
Heartburn, reflux of stomach contents into esophagus, worse when supine, bending over, coughing→ dysphagia
Tx: surgical repair; eat many small meals- do not lie down after eating
GERD- gastroesophageal reflux disease
tomach contents irritate lining of esophagus causing I/N/F→ scarring→stenosis
Clinical manifestations: heartburn 30-60 mins after eating
pepic ulcers is mainly cuased by…manifestations….
H pylori infection, characterized by Pain 2-3 hours after meal/ when lying down and relieved by eating food, heartburn, N/V, weight changes, risk of iron deficiency, occult blood in stool
gastritis
inflammation of stomach
acute ( spicy food),chronic (alcohol abuse), gastoenteritis ( infection of the stomach)- staph
gallstones (cholelithiasis)
too much cholsterol/billirubin
common in females, + cholesterol diets, multipar—> inflammation, jaundice, pancreatitis, colicky RUQ pain (reffered)
what causes jaundice?
too much conjugated/unconjugated billirubin
( unconjugated= difficult to clear/conjugated–> cuaes puritis)
hepatitis
can be viral/toxic–> can cause necrosis and scarring of the liver,
pre-icteric:jaundice/fatigue, Nausea, headache, RUQ pain, eleated liver enxymes
Icteric: Intrahepatic jaundice→ CM of jaundice
Bilirubin may be conjugated→ dark urine, pruritus, enlarged & tender liver, trouble making bile→ light coloured stool
post-icteric: recovery ( 16 weeks)
cirrohsis
diffus fibrosis of liver/los of organization
1) fatt liver ( alchoholism)
2) alcohol hepatitis: chronic inflammation–> necrosis of hepatocytes
3)end stage–> failure
loss of hepatocyte function causes ….
- Impaired metabolism of macromolecules, drugs
Impaired digestion/absorption of lipids
Prolonged clotting times
Decreased conjugation of bilirubin
loss of bile causes…
- impaired digestion/absorption of lipids, post-hepatic jaundice if the bile ducts= compressed by scarring
Portal HTN: splenomegaly, esophageal varices, ++ pressure in the mesenteric GI vessels, ascites
acute pancreatitis
ob of the duct (alc abuse)
chronic pancreatitis
chronic inflammtion—. necrosis/fibrosis/alt hormone secretion
cIBD/CHronhs disease
inflammation & excessive release of cytokines—> lesions of the mucosa in the SI
ulcerative colitis
Inflammation of excessive release of cytokines stress, inflammation in rectum, moves proximally, deeper lesion—> submucosa
appendicitis
bacteria reproduce causing inflammation, swelling & compression of BV→ ischemia→ necrosis of walls-peritonitis
Manifestations: periumbilical pain, severe LRQ pain n/v, bursts can go away and be more diffuse, hypotension/tachycardia, systemic signs of inflammation
Peritonitis:
chemical causes ex: pancreatitis
bacterial: burst appendix
Patho:
Bowel inflammation__> ++ permeability allowing bacteria to leave the GI tract and infect the peritoneum
Exudate secreted by the peritoneum to seal fluids, bacteria→ formation of abscess
Abdominal distention→ contraction of abdominal muscles
Fluid in the peritoneal space
peritonitis manifestations
Sudden-diffuse pain that’s exacerbated when moving
N/V from p, irritation of intestines
Trouble breathing
Hypovolemia ( shocky)- pallor, dry, tachycardia hypotension
Abdo distention/rigidity
No bowel sounds→ secondary functional ob→ paralytic ileus
intestinal ob
Mechanical or functional
Patho: mechanical
Stretch of smooth muscle before ob→ cells of S.M contract increasing p in veins→ edema
Excess of fluids leads to emesis—> imbalances
Loss of motility, -bowel sounds
Inflammation due to bacterial overgrowth—> peritonitis→sepsis
Patho:functional
Same as mechanical though no reflex of the S.M
intestinal ob manifestations:
SI
Severe colicky pain during s.m contraction w sounds, paralytic ileus ( no sounds), V of materials before the ob & may include bile ( poop), anxiety, diaphoresis, tachycardia, hypovolemia/dehydration—> shock
LG
slowly/milder CM, mild pain, C/A, when abdo→distended=more p
