GI Physio + etc. Flashcards
What are the actions of gastrin?
- Increase gastric H+
- Increase gastric mucosa growth
- Increase gastric motility
Describe the physiological cause of achalasia.
Death of intramural inhibitory ganglion cells containing NO and VIP
What positively regulates gastrin secretion?
Negatively?
- Positive: increased gastric distension/alkalinization, AAs, peptides, vagal
- Negative: pH < 1.5
What cells (of what organ) secrete CCK?
I cells of duodenum, jejunujm
What’s the function of pepsin?
Protein digestion
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)
In what state is motilin increased?
Fasting
What cells (of what organ?) release pepsin?
Chief cells of the stomach
What cells (of what organ?) release gastric acid?
Parietal cells of the stomach
What cells (of what organ) secrete secretin?
S cells of duodenum
What is the action of somatostatin?
Decreases release of all GI hormones
What are the actions of secretin?
- Increase pancreatic bicarb secretion
- Increase bile secretion
- Decrease gastric H+
What 2 things release amylase?
Salivary glands; pancreas
What are the functions of glucagon?
- Stimulate glycogenolysis to increase serum glucose
2. Favors gluconeogensis- conversion of amino acids to glucose
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)
What cells (of what organ?) release HCO3-?
Mucosal cells of the stomach, duodenum, salivary glands, pancreas
Where are the following absorbed: Fe, folate, B12, bile acids?
Iron: Absorbed as Fe2+ in duodenum
Folate: Jejunum
Vitamin B12: Ileum
Bile Acids: Ileum
What are the actions of NO?
Increase smooth muscle relaxation, including LES
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.
- Bound to proteins when eaten
- Salivary glands secrete R-binder in mouth
- B12’s surrounding proteins separated in the stomach by stomach acid/enzymes
- B12 binds R-binder in the stomach
- Parietal cells secrete IF in the stomach
- B12-R-binder complex separated by pancreatic proteases s/p CBD
- B12 binds IF
- B12-IF complex absorbed in the distal ileum
- 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
