L5: Concepts of GI Disease (Gallagher)

Question 1

3 major functions of stomach**

Answer 1

filling (reservoir for food and liquid)
mixing (with gastric secretions to begin digestion)
emptying (to gradually empty partially digested food into the intestine)

Question 2

2 components of gastric filling*

Answer 2

• receptive relaxation (relaxation of upper esophageal –> lower esophageal sphincter –> fundus after swallowing)
• accommodation (distention of fundus without increase in intra-gastric pressure)

Question 3

inflammatory and neoplastic disease –> gastric filling**

Answer 3

• failure to relax

- increase in postprandial intragastric pressure –> pain, nausea, v

Question 4

what 3 compounds induce acid secretion during gastric mixing*

Answer 4

gastrin
histamine
Ach
(stimulate parietal cells)

Question 5

anatomic and chemical defense mechs. of gastric mucosal barrier*

Answer 5

• 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

Question 6

consequences of broken gastric mucosal barrier**

Answer 6

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

Question 7

mucosal erosions or ulcers occur in what dz processes?*

Answer 7

• gastric dz
• liver dz
• uremia
• hypoxia
• shock
• sepsis
• drugs

Question 8

fx of fundus and body

Answer 8

storage

Question 9

fx of antrum

Answer 9

grind, mix, empty

Question 10

fx of pylorus

Answer 10

prevent food particles >2mm from leaving stomach

Question 11

stomach empties only when:

Answer 11

intragastric P > duodenal P + pyloric resistance

-influenced by chem. comp. of food, food type, pH and osmolarity

Question 12

gastric motility and emptying disrupted by:

Answer 12

gastric and SI dz (most delay emptying and cause v)

Question 13

gastric outlet obstruction –>

Answer 13

gastric distention and stasis

Question 14

normal emptying time for dog

Answer 14

12-14h

Question 15

vomiting occurs when:**

Answer 15

vomiting center receives sufficient stim. to reach threshold and initiate reflex
-well developed in dogs, cats

Question 16

see slide 21**

Answer 16

(vomiting reflex)

Question 17

3 phases of vomiting

Answer 17

nausea (pacing, drooling)
retching (abd. contractions)
vomiting (expulsion)

Question 18

diarrhea

Answer 18

an increase in fecal water content which results in a change in the frequency, fluidity and V of bowel movements

Question 19

where is majority of water resabsorbed?**

Answer 19

SI (jejunum and duodenum)

Question 20

functional unit of SI

Answer 20

the villus

Question 21

fx of villous crypt

Answer 21

secrete water/electrolytes

Question 22

fx of cells between villous crypt and tip

Answer 22

digestion of protein and carbs

Question 23

fx of villous tip

Answer 23

fluid and electrolytes absorbed

Question 24

5 mechs. of diarrhea**

Answer 24

osmotic
secretory
exudative
disordered motility
mixed

Question 25

osmotic diarrhea

Answer 25

• failure to digest or absorb nutrients –> excess of water-soluble molecules are retained in the bowel lumen
• can be due to Exocrine Pancreastic Insufficiency (EPI) where highly osmotic particles in GIT can’t be broken down and absorbed and attract water to them, or SIBO

Question 26

acute viral diseases that cause d

Answer 26

coronavirus
parvovirus
rotavirus

Question 27

secretory diarrhea

Answer 27

stimulation of excess secretion overwhelms absorption (normally, absorption just barely counteracts what’s being secreted)

Question 28

fat malabsorption

Answer 28

unabsorbed fatty acids are hydroxylated by enteric bacteria

• results in steatorrhea (excess fat in feces)
• can occur with EPI

Question 29

exudative diarrhea (increased mucosal permeability)

Answer 29

caused by leakage of tissue fluid, serum proteins, or blood through the intestinal tract

Question 30

causes of exudative diarrhea

Answer 30

• lymphangiectasia
• dec. oncotic P (hypoalbuminemia)
• inc. hydrostatic P (R-sided CHF, Portal hypertension)

Question 31

disordered motility diarrhea

Answer 31

• usually 2ary to something else
• the slower things move, the more fluid gets absorbed; however, osmotic diarrhea has both dec. motility and dec. fluid absorption

Question 32

most diarrhea is what type:

Answer 32

MIXED! (results from multiple factors)