L5: Concepts of GI Disease (Gallagher) Flashcards
3 major functions of stomach**
filling (reservoir for food and liquid)
mixing (with gastric secretions to begin digestion)
emptying (to gradually empty partially digested food into the intestine)
2 components of gastric filling*
- receptive relaxation (relaxation of upper esophageal –> lower esophageal sphincter –> fundus after swallowing)
- accommodation (distention of fundus without increase in intra-gastric pressure)
inflammatory and neoplastic disease –> gastric filling**
- failure to relax
- increase in postprandial intragastric pressure –> pain, nausea, v
what 3 compounds induce acid secretion during gastric mixing*
gastrin
histamine
Ach
(stimulate parietal cells)
anatomic and chemical defense mechs. of gastric mucosal barrier*
- surface mucus
- bicarbonate
- epithelial cells
- mucosal blood flow (delivers bicarb, removes H ions before they can do any damage)
- prostaglandins (inc. mucus production)
- basal membrane
consequences of broken gastric mucosal barrier**
H diffuses into BM –> activation and degranulation of mast cells –> histamine release –» hemorrhage, pain, failure to distend, n/v, mucosal erosions or ulcers
-more common in dogs than cats
mucosal erosions or ulcers occur in what dz processes?*
- gastric dz
- liver dz
- uremia
- hypoxia
- shock
- sepsis
- drugs
fx of fundus and body
storage
fx of antrum
grind, mix, empty
fx of pylorus
prevent food particles >2mm from leaving stomach
stomach empties only when:
intragastric P > duodenal P + pyloric resistance
-influenced by chem. comp. of food, food type, pH and osmolarity
gastric motility and emptying disrupted by:
gastric and SI dz (most delay emptying and cause v)
gastric outlet obstruction –>
gastric distention and stasis
normal emptying time for dog
12-14h
vomiting occurs when:**
vomiting center receives sufficient stim. to reach threshold and initiate reflex
-well developed in dogs, cats
see slide 21**
(vomiting reflex)
3 phases of vomiting
nausea (pacing, drooling)
retching (abd. contractions)
vomiting (expulsion)
diarrhea
an increase in fecal water content which results in a change in the frequency, fluidity and V of bowel movements
where is majority of water resabsorbed?**
SI (jejunum and duodenum)
functional unit of SI
the villus
fx of villous crypt
secrete water/electrolytes
fx of cells between villous crypt and tip
digestion of protein and carbs
fx of villous tip
fluid and electrolytes absorbed
5 mechs. of diarrhea**
osmotic secretory exudative disordered motility mixed
