GI Physio + etc. Flashcards by Dave Ed

What are the actions of gastrin?

Increase gastric H+
Increase gastric mucosa growth
Increase gastric motility

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Describe the physiological cause of achalasia.

Death of intramural inhibitory ganglion cells containing NO and VIP

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What positively regulates gastrin secretion?

Negatively?

Positive: increased gastric distension/alkalinization, AAs, peptides, vagal
Negative: pH < 1.5

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What cells (of what organ) secrete CCK?

I cells of duodenum, jejunujm

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What’s the function of pepsin?

Protein digestion

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Give 4 (low yield) examples of bugs that cause WATERY diarrhea, and their unique associations.

ETEC (Traveler’s diarrhea)
Vibrio cholera (comma-shaped, a/w rice, no abd pain)
C-diff (pseudomembranous colitis; clindamycin/PCN)
C. perfringens (can cause gangrene)

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In what state is motilin increased?

Fasting

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What cells (of what organ?) release pepsin?

Chief cells of the stomach

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What cells (of what organ?) release gastric acid?

Parietal cells of the stomach

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What cells (of what organ) secrete secretin?

S cells of duodenum

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What is the action of somatostatin?

Decreases release of all GI hormones

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What are the actions of secretin?

Increase pancreatic bicarb secretion
Increase bile secretion
Decrease gastric H+

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What 2 things release amylase?

Salivary glands; pancreas

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What are the functions of glucagon?

Stimulate glycogenolysis to increase serum glucose

2. Favors gluconeogensis- conversion of amino acids to glucose

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Name the bugs that cause food-poisoning, and their associated foods.

Vibrio parahemolyticus, vulnificus (seafood, water)
Bacillus cereus (reheated/fried rice)
S. aureus (meat, mayo, custard)
C. perfringens (reheated meat dishes)
C. botulinum (improperly canned foods)
E. coli O157:H7 (undercooked meat)
Salmonella (poultry, eggs, meat)

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What cells (of what organ?) release HCO3-?

Mucosal cells of the stomach, duodenum, salivary glands, pancreas

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Where are the following absorbed: Fe, folate, B12, bile acids?

Iron: Absorbed as Fe2+ in duodenum

Folate: Jejunum

Vitamin B12: Ileum

Bile Acids: Ileum

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What are the actions of NO?

Increase smooth muscle relaxation, including LES

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What are the 2 phases of swallowing?

What CN’s are important for the 2nd phase?

Voluntary phase (striated m.)

2. Pharyngeal stage (CNs V, VII, IX, X, XII)

Name some bugs that cause BLOODY diarrhea, and there unique associations.

Campylobacter (grows at 42C; Reiter’s syndrome)
Salmonella (lactose-neg, poultry/turtles)
Shigella (lactose-neg, HUS)
EHEC O157:H7 (HUS; undercooked hamburgers)
Enteroinvasive E. coli (contaminated cheese/water)
Yersenia enterocolitica (day-care; pseudoappendicitis)

Name the pancreatic proteases

Trypsin, chymotrypsin, elastase, carboxypeptidase

What are the actions of vasoactive intestinal peptide?

Increase intestinal water/electrolyte secretion

- Increase relaxation of intestinal smooth muscle and sphincters

What positively regulates secretin release?

H+, fatty acids in duodenum lumen

What organ secretes motilin?

Small intestine

What positively regulates CCK release?

Fatty acids, AAs

What cells (of what organ) secrete gastric inhibitory peptide (GIP)?

K cells of the duodenum, jejunum

What cells (of what part of the stomach) secrete gastrin?

G cells of the antrum

What initially activates trypsinogen?

Enterokinase/enteropeptidase from brush border enzymes in duodenum - Active trypsin can go on to activate more trypsinogen

What cells (of what organ?) release IF?

Parietal cells of the stomach

What secretes lipase?

Pancreas

What are the actions of GIP (think of it as glucose-dependent insulinotropic peptide)?

- Increase insulin | - Decrease gastric H+ (at very high concentrations; this is mainly the job of secretin)

What compounds positively regulate gastric acid secretion? | Negatively?

- Positive: histamine, ACh, gastrin | - Negative: somatostatin, GIP, prostaglandin, secretin

What are the actions of motilin?

Produces migrating motor complexes

What positively regulates pepsin secretion?

Vagal stimulation, local acid

What cells (of what organ) secrete vasoactive intestinal peptide (VIP)?

Parasympathetic ganglion in sphincters, GB, and small intestine

What are the actions of CCK?

- Increase pancreatic secretions - Increase GB contractions - Decrease gastric emptying - Decrease gastric H+

How is GIP release positively regulated?

Fatty acids, AA's, and oral glucose

What positively regulates somatostatin secretion? | Negatively?

- Positive: acid | - Negative: vagal stimulation

What positively regulates VIP secretion? | Negatively?

- Positive: distension and vagal stimulation | - Negative: adrenergic input

What cells (of what organ) secrete somatostatin?

D cells of pancreatic islets, GI mucosa

Describe B12's path to absorption.

1. Bound to proteins when eaten 2. Salivary glands secrete R-binder in mouth 3. B12's surrounding proteins separated in the stomach by stomach acid/enzymes 4. B12 binds R-binder in the stomach 5. Parietal cells secrete IF in the stomach 6. B12-R-binder complex separated by pancreatic proteases s/p CBD 7. B12 binds IF 8. B12-IF complex absorbed in the distal ileum 9. B12 travels in the blood via transcobalamin

What's another name for nematodes? Trematodes? Cestodes?

Nematodes: roundworms Trematodes: flatworms or flukes Cestodes: segmented tapeworms

What's the name of the raccoon version of Toxocara canis (dog) Toxocara catis (cat), all of which cause larvae migrans?

Baylisascaris procyonis

What bug has the characteristic football shape w/polar plugs at each end, and also causes rectal prolapse? What's the tx?

Trichuris trichuria (trichuriasis) “Playing football gives you trii-trunk anal prolapse and the bends” Tx: albendazole

What's the name of the bug the NW med students got thru eating snails or seafood that ate snails in Jamaica?

Angiostrongylus cantonensis - Causes eosinophilic meningitis

Name 2 lymphatic filariasis infection bugs. What bacterium are they symbiotic w/? What's another bug that has the same symbiont?

Wuchereria bancrofti (“Witch”), Brugia malayi – symbiotic Wolbachia bacteria (also w/Onchocerca volvulus)

Besides strongyloides, what's another parasite that can cause autoinfection? What type of worm is it? (trematode, cestode, nematode)

Hymenolepsis nana (cestode/tapeworm, very small) "na na, I caused an autoinfection" - Acquired by ingestion of ova (human or rodent feces) or flea - Clinical: Enteritis may occur with multiplication - Diagnosis: Ova in feces