Lecture 37 - Gastric Motility & Vomiting Flashcards

1
Q

what inhibits gastric acid secretion

A
  1. stimuli that promote acid secretion are no longer active
  2. low intragastric pH, D cells secrete somatostatin inhibiting release
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2
Q

Fundus

A

receives and stores ingesta and adapts to increases in volume

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3
Q

Gastric body

A

mixes saliva and gastric juice with food

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4
Q

Antrum

A

regulates the propulsion of food past the pyloric sphincter into the duodenum

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5
Q

Pylorus

A

allows small amounts of finely ground liquid chyme to pass

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6
Q

what are the 4 functions of the stomach

A
  1. storage
  2. grinding of food
  3. controlled delivery rate to duodenum
  4. acid secretion and regulation
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7
Q

Gastrin ____ acid secretion while somatostatin ____ it

A

increase; decrease

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8
Q

T/F: gastric distension activates the vagus nerve directly

A

TRUE

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9
Q

describe the motility of the proximal stomach

A

tonic contractions (weak)
storage of food

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10
Q

describe the motility of the distal stomach

A

slow wave, intense peristalsis
propel, grind, and mix

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11
Q

what 2 substances inhibit gastric motility

A
  1. secretin
  2. cholecystokinin
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12
Q

describe the migrating motor complex

A

distinct pattern of electromechanical activity in GI smooth muscle during fasting regulated by motilin

“housekeeper” = non-selective, larger particles

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13
Q

what are the components of the afferent limb for the vomiting apparatus

A
  1. chemoreceptor trigger zone (4th ventricle)
  2. Vestibular apparatus
  3. Abdominal viscera
  4. Cerebral Cortex
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14
Q

T/F: H1-histaminergic receptors in the CRTZ and vestibular apparatus are more important in cats than dogs

A

FALSE

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15
Q

T/F: ruminants undergo internal vomiting by ejecting abomasal contents into the rumen

A

TRUE

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16
Q

T/F: horse vomiting is rare

17
Q

describe vomiting clinical signs in 5 steps

A
  1. nausea, hypersalivation
  2. reverse peristalsis
  3. inspiration against closed glottis (- intrathoracic pressure)
  4. abdominal contraction (+ abdominal pressure)
  5. gag
18
Q

what are the 3 ways we can make animals vomit? what do they stimulate?

A
  1. hydrogen peroxide - pharynx and stomach
  2. dopamine receptor agonists (apomorphine/ropinirole) - CTZ
  3. alpha 2 agonists - CTZ in cats
19
Q

give the receptors and species the listed emetic effects:

xylazine/dexmedetomidine

A

a2 agonist
cat

20
Q

give the receptors and species the listed emetic effects:

apomorphine

A

dopamine agonist
dog

21
Q

give the receptors and species the listed emetic effects:

ropinirole

A

dopamine agonist
dog

22
Q

give the receptors and species the listed emetic effects:

hydrogen peroxide

A

irritation/inflammation
dog

23
Q

what substances are responsible for stimulating abdominal viscera in dogs and cats

24
Q

what anti-emetic blocks serotonin? what receptor is blocked?

A

ondansetron; 5HT

25
what substances are responsible for stimulating CTZ in dogs and cats
dogs = dopamine, norepinephrine cats = norepinephrine
26
what anti-emetic blocks dopamine? what receptor is blocked?
metoclopramide; D2
27
what anti-emetic blocks norepinephrine? what receptor is blocked?
chlorpromazine; a2
28
what substances are responsible for stimulating the vestibular apparatus in dogs and cats
dogs = histamine cats = acetylcholine
29
what anti-emetic blocks histamine? what receptor is blocked?
diphenhydramine; H1
30
what substances are responsible for stimulating the vomiting center directly in dogs and cats
dogs = substance P, norepinephrine cats = serotonin, substance P, norepinephrine
31
what anti-emetic blocks substance P? what receptor is blocked?
maropitant; NK1
32
what are the 4 metabolic consequences of vomiting
1. loss of HCl (alkalosis) 2. loss of HCO3 (acidosis) 3. loss of K+ (hypokalemia) 4. loss of H2O (dehydration, hypovolemia)
33
duodenal V+
simple stomach animals, reverse peristalsis
34
gastric V+
pyloric outflow obstruction in ruminants and humans