GI fluid & Electrolyte Transport Flashcards
what are the two ways water can be absorbed
paracellular
tight junctions
water absorption or movement to the blood side is predominantley going to occur in what pathways
paracellular
transcellular
in paracellula rpathway when sodium goes through
water will also go through
what channels for transcellular route
water channels
what has the leakiest tight junctions
duodenum
what has the tightest tight junctions
colon
most of water and electorlight absorption is where
at beginning of SI
solvent drag
bulk movement
where is solvent drag greatest
beginning of GI
draw out water movement from tubular fluid to cell to blood
pg 6
draw out epithelial cell of duodenum and the transporters involved
pg 7
why is sodium potassium ATPase not on lumen side
come in through secodndayr active transport and will get kicked out
duodenum is major site of absorption for
CHO, Protein & Lipid Absorption
where is the major site for sodium absorption
jejunum
what is function of colon
finish off water and electrolight absorption - it is not the major site!
if you have diaghrrea what happens to potassium in blood
low potassium in blood, more loss of potassium
hypokalemia in
diarrhea
what are the two ways you can get diarrhea
Decreased absorption of fluid and electrolytes
Increased secretion of fluid and electrolytes
why is there loss of bicarb in diarrhea?
so many things secrete bicarb, so you will loose a lot of it when you have diarrhea.
salt and solute transport is driving force for passive water flux by what two routes
paracellular or transcellular routes
sodium and chloride are absorbed in large quantities by what cells
intestinal epithelial cells
duodenum is major site for absorption of what
CHO, Protein & Lipid Absorption
jejunum is major site for absorption of what
Na+
draw out epithelial cell of SI (duodenum & jejunum)
pg 7
where is there net NaHCO-3 absorption
duodenum & jejunum
draw out epithelial cell of ileum
pg 9
where is there net NaCl absorption
Ileum
draw out epithelial cell of colon
pg 10
synthesis of Na+ channels in colon is induced by
aldosterone
synthesis of aldosterone in colon leads to increased
Na+ absorption & K+ secretion
how does aldosterone increase K+ secretion in colon
increases # of Na+ channels
what does diarrhea do to K+
hypkalemia - low K+. increased K+ secretion which results in loss of K+
what are the major anions of the colon
organic acids (short-chain fatty acids)
show the effect of short chain fatty acids on colon
pg 12
diarrheal fluid has high concentration of
HCO3- & K+
why does diarrheal fluid have high concentration of HCO3-
b/c fluids secreted into gastrointestinal tract have high HCO3- content
loss of HCO3- in diarrhea causes
hyperchloremic metabolic acidosis
why does diarrheal fluid have high concentration of K+
flow-rate dependent K+ secretion by colon
excessive loss of K+ from GI results in
hypokalemia
what will decreaed surface area in GI do
decreased surface area caused by infection or inflammation will lead to decreased absorption of nutrients and vitamins and could lead to diarrhea
celiac disease is inflammatory condition directed against what antigen
gluten/gliadin
celiac disease is inflammatory condition directed against what autoantigen
tissue transglutaminase (tTG)
what is another name for celiac disease
gluten-sensitive enteropathy
what kind of test has the most power to exclude celiac disease
genetic test
list diagnosis and treatment of celiac disease
Positive serologic tests and upper endoscopy with biopsy
Genetic test has most power to exclude celiac disease
Symptoms resolve on a gluten-free diet
Repeat small bowel biopsy to document normalization on a gluten-free diet is no longer recommended to establish the diagnosis
what is another term for gluten
gliadin
what is treatment for celiac disease
gluten-free diet & glucocorticoid
what causes tropical sprue/what is it?
happens in tropics
unidentified infectious agents that damage mucosa
what is treatment for tropical sprue?
antibiotics
what is an example of osmotic diarrhea
lactase deficiency
what causes osmotic diarrhea
caused by presence of nonabsorbable solutes in lumen of intestine
what causes secretory diarrhea
excessive secretion of fluid by crypt cells
overgrowth of what will cause secretory diarrhea
enteropathic bacteria like E.Coli or Vibrio cholerae (cholera)
secretory diarrhea vomitting sunken eyes & cheeks decreased skin suppleness dry mucous membrane urine stopped or decreased these are symptoms of
cholera
draw out the mechanism of cholera
pg 34
bacterial toxin cholera enters what cells
intestinal crypt cells
how does cholera toxin enter intestinal crypt cells
apical memrane
once inside intestinal crypt cell what does cholera toxin do
moves to basolateral membrane
once in basolateral membrane what does cholera toxin do
catalyzes ADP of as subunit of Gs protein that is coupled to adenylyl cyclase, which makes it permanetly GTP
what are the treatments for cholera
Oral Rehydration
Intravenous Rehydration
Antimicrobial Therapy
review the major sites of absorption
pg 37
