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OST 575 - Exam |Questions with 100% Correct Answers
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OST 575 - Exam |Questions with 100% CorrectAnswers
What is the purpose of vitamin B12 for humans? - ✔️✔️-serves as co enzyme for conversion of
homocysteine to methionine
-serves as co enzyme for conversion of methylmalonyl co enzyme A (CoA) to succinyl CoA
What are the major symptoms of B12 deficiency? - ✔️✔️hematologic (due to impaired
tetrahydrofolate)
neuropsychiatric abnormalities (disordered folate metabolism)
Do humans have vitamin B12 naturally or is it something that needs to be consumed? -
✔️✔️Needs to be consumed (usually from animal products)
What are some conditions that cause cobalamin deficiency? - ✔️✔️achlorhydria with pepsin
deficiency
pancreatic protease deficiency
IF deficiency (*pernicious anemia*)
Lack of absorptive carriers for Cbl-IF (ileum resection, inflammation)
bacterial overgrowth
How are vitamin B12 and IF absorbed in the ileum? - ✔️✔️as a *complex* that binds to a specific
carrier on brush border of distal ileum for cobalamin(B12) absorption
What are the effects of alcohol on the GI tract? - ✔️✔️esophageal reflux (due to LES relaxation)
esophageal damage (from frequent vomiting)
gastritis and mucosal damage
malabsorption and diarrhea
,Decreased hepatic synthesis of chalk acid and alters bile pool
What are the effects of bacterial overgrowth in the GI tract? - ✔️✔️bacteria utilize B12-->
deconjugate bile salts-->
ferment carbohydrates (produces CO2 and H gas)-->
toxic to enterocytes *leading to villus atrophy* =
MALABSORPTION
What are luminal problems that contribute to malabsorption? - ✔️✔️pancreatic insufficiency
(*oil in stool*)
bile acid insufficiency
zollinger-ellison syndrome
Where is the myenteric plexus found? submucosal plexus? - ✔️✔️myenteric = between
longitudinal and circular muscle layers
submucosal = submucosa (between circular muscle and mucosa layers)
What do the submucosal neurons control? - ✔️✔️local blood flow
absorption and secretion functions of mucosal epithelial cells
What do myenteric neurons control? - ✔️✔️gut motility
BER is initiated in the ___________ cells and it is propagated into the muscle layers through
____________ connections between ICC and smooth muscle cells? - ✔️✔️Interstitial cells of Cajal
(ICC)
gap junctions
,What is the significance of gap junctions for gut motility? - ✔️✔️low resistance intercellular
connections that allow passage of electrical and chemical signals (Ca++) through groups of cells
What clinical diagnosis can cause a reduced number of interstitial cells of Cajal in the stomach
to impair gastric emptying and cause idiopathic gastroparesis? - ✔️✔️diabetic patients can
experience this
Reduced numbers of Interstitial cells of Cajal in the COLON of patients will slow what? -
✔️✔️slow transit constipation
What is the mixing mechanism in the intestines? what is the movement mechanism in the
intestines? - ✔️✔️Segmentation = MIXING
Peristalsis = MOVING
What is Kaolin medication? MOA? - ✔️✔️naturally occurring hydrated aluminum silicate used as
an anti-diarrheal
*binds bacterial toxins and may protect irritated mucosa*
What is the MOA of Bismuth subsalicylate (peptic-bismol)? - ✔️✔️believed to bind bacterial
toxins and have a cytoprotectant action
What is the MOA of Alosetron (lotronex) anti-diarrheal? - ✔️✔️blocks 5-HT3 receptors and
relieves symptoms in *female, diarrhea predominant IBS patients ONLY*
Reduces stool frequency, urgency, abdominal pain
What are some severe side effects of Alosetron? - ✔️✔️can cause severe constipation and
ischemic colitis
What medication has a significant side effect of constipation and can be used as an anti-
diarrheal? - ✔️✔️Opiate drugs
, What is the MOA of opiates as anti-diarrheal medications? - ✔️✔️inhibit release of NO and VIP to
stimulate non-propulsive motility and delay transit through GI tract
What are the types of Opiate anti-diarrheal medications? - ✔️✔️Diphenoxylate (Lomotil)
Loperamide (Imodium)
Eluxadoline (Viberzi)
What is the MOA of Diphenoxylate (lomotil)? What is it normally combined with? -
✔️✔️decreases propulsive motility - LO Motile (causes non-propulsive contractions)
*combined with atropine*
What are the side effects of Diphenoxylate and Loperamide? - ✔️✔️cramps
nausea
What is the MOA of loperamide (imodium)? Why is loperamide a great anti-diarrheal drug? -
✔️✔️Decreases propulsive motility
*Does NOT cross BBB limiting abuse potential*
What is the MOA of Eluxadoline (Viberzi)? - ✔️✔️acts at multiple opiate receptor subtypes to
decrease propulsive motility
What anti-diarrheal medication has been approved for use in diarrhea predominant IBS
patients? - ✔️✔️Eluxadoline
What are the Prokinetic drugs (motility enhancing) useful for treating? - ✔️✔️post-surgical ileus
delayed gastric emptying or delayed intestinal transit from autonomic neuropathies (diabetes)
GERD
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