Also, this subject I found rather complex so if anyone (especially the experts) feels I left out something important please add a message.

QUESTIONS

1. The stomach has a pacemaker located in the _______________.  It produces peristaltic waves according to a rhythm called the _______________.
    
2. Does the cardia demonstrate peristalsis?
    
3. The presence of food in the pylorus causes pyloric contraction &
   retropulsion of food back into the antrum for grinding.  Gastrin causes pyloric relaxation so that ingesta can finally get out. Before there is much gastrin produced, food passes from the pylorus according to particle size.  How small does food have to be to escape?
   
   a) <10mm diameter
   
   b) < 25 mm diameter
   
   c) <2mm diameter
   
   d) <5mm diameter
   
   To delve into this a little deeper, which empties from the stomach faster:  liquids or solids?
   Which empties from the stomach fastest:  protein, fat, or carbohydrate?
    
4. The pacemaker's rhythm, force of contraction & relaxation of the fundus during filling are controlled by fibers in what nerve?  The change in smooth muscle tone as the stomach fills allows intragastric pressure to remain unchanged (the stomach can really fill up without a pressure change).  The name of this phenomenon is _______________.
    
5. What is the "enterogastric effect?"
    
6. Although gastric contraction is mostly neuro modulated, there is some hormonal influence. Gastrin causes increased circular muscle contractions and leads to pyloric relaxation (the overall effect is to drive ingesta into the duodenum). Gastrin is produced by what cells? Where are they located?
    
7. Why would you die if your stomach was completely removed and what would you die of?
    
8. What is the normal gastric emptying time?  If you see prolonged gastric emptying time you have one of what two abnormal conditions? _______________ or _______________.
    
9. What stimulates Gastrin secretion?
    
10. The three chemical stimuli for hydrochloric acid secretion are _______________, _______________, and _______________.
     
11. Chief cells and parietal cells.  Both are in the antrum. Which produces HCl & which produces pepsinogen?
     
12. Where might one find H2 receptors?
     
13. There are 3 phases of gastric secretion:
    
    The _______________ phase is controlled by mental input (smell of food, cool looking Burger King commercial, etc.) & by food in the oropharynx. The brain activates the G cells, the
    parietal cells, & the chief cells. The next stage is the _______________ phase which activates G cells & a parietal cells when gastric distension is perceived.  The _______________ phase which is stimulated by when food hits the duodenum.
     
14. What is the significance of pylorospasm?
     
15. What are Interdigestive motor complexes?
     
16. If you cannot give reglan orally, what is the next best route?
     
17. The most common clinical sign associated wtih gastric disease is ____________.
18. The most common GI neoplasm of the dog and cat is _________________.
    
    
    
     

ANSWERS

1. The pacemaker is located in the pacemaker and the rhythm is called the "Basic Electrical Rhythm."
   
   
   
   
    
2. The cardia does not demonstrate peristalsis. Instead it has a steady tone which pushes food down toward the antrum for grinding.
   
   
   
   
    
3. Food must be < 2mm in diameter to leave the pylorus at this point in digestion.  Liquid empties faster than solid stomach contents and carbohydrate empties faster than protein which empties faster than fat. This is probably a good time to note that erythromycin works as a motility modifier by allowing very large particles to leave the stomach like the 5mm size. These  particles are pretty big and may not absorb normally further down.
   
   
   
   
    
4. This relaxation phenomenon is called "reactive or adaptive relaxation."
   
   
   
   
    
5. The enterogastric reflex is a reflex which reduces gastric peristalsis as soon as ingesta is perceived in the duodenum.
   
   
   
   
    
6. Gastrin is produced by the G cells which are also called the
   enterochromaffin cells.  These cells are found in the antrum & pylorus.
   
   
   
   
    
7. Intrinsic factor is produced in the stomach. Without it you can wave goodbye to B12 absorption.  You would develop pernicious anemia from your B12 deficiency.
   
   
   
   
    
8. Normal gastric emptying time is about 5 hours (is this only for dogs?) If you have a prolonged gastric emptying time you either have an obstruction or a motility disorder.
   
   
   
   
    
9. Gastrin secretion is stimulated by gastric distension and by digestive proteins on the stomach surface. According to what I've found, both HCl secretion & pepsin secretion are stimulated by the same events. (gastrin, distension etc)
   
   
   
   
    
10. The three chemical stimuli for hydrochloric acid secretion are
    acetylcholine, histamine, & gastrin.
    
    
    
    
     
11. When I was in school, Dr. Curry told us to remember that "there is no PP in the stomach." The parietal cells produce HCl and the chief cells produce pepsinogen.
    
    
    
    
     
12. H2 receptors are found in the basement membrane of the parietal cells.
    
    
    
    
     
13. The three phases of gastric secretion are the cephalic stage, the gastric stage and the intestinal stage.
    
    
    
    
     
14. The significance of pylorospasm is that it doesn't seem to exist in the natural state. It was once thought be involved in motility problems and the use of anticholinergic drugs was widespread to suppress this pylorospasm. (It is since been determined that if you use anticholinergic drugs to treat GI disorders, you will go blind and perhaps God will come out of the sky and strike you dead - at least that's what Dr. Strombeck said when I was in school.)
    
    
    
    
     
15. Interdigestive motor complexes are also called "housekeeper contractions" and are used to sweep out undigested stuff on down & out of the stomach. Cats do not have these
    complexes and it is thought that this may be why hairballs are so commonly observed when the feline stomach is endoscoped.
    
    
    
    
     
16. The next best route for reglan is SQ.  When given IV reglan is
    inactivated in 1-3 minutes.  When given IM it is inactivated in 5-10 minutes (Okay, okay, if you need to suppress nausea, too, an IV drip may be the best.)
    
    
    
    
     
17. The most common clinical sign associated with gastric disease is anorexia. (I bet you thought it was vomiting)
    
    
    
    
     
18. The most common GI neoplasm in both dogs and cats is the adenocarcinoma (71% of all GI neoplasms in the dog and 58% in the cat). Lymphoma is #2.