Chapter 4: Chloride Flashcards
Chloride makes up what percentage of plasma and remaining ECF?
2/3
Which is the major anion filtered by the glomerulus?
Chloride
What is average chloride for dogs? For cats?
Dogs 110 mEq/L
Cats 120 mEq/L
True or false: chloride is higher in arterial blood when obtained anaerobically?
True. Due to the chloride shift, chloride moves intracellularly due to the effects of deoxygenated hemoglobin in exchange for bicarbonate.
The chloride shift happens easily due to RBC having a higher resting membrane potential (-15 mV)
List the permeability of chloride when being reabsorbed in the following: jejunum, ileum and colon
Most permeable: colon
Middle: Jejunum
Least: Ileum
What percentage of chloride is reabsorbed in the proximal tubules?
50-60%
Through what channels is chloride reabsorbed in the proximal tubules?
Luminal: Formate-chloride exchange mechanism
Basolateral: K+-Cl- cotransporter
Other than the proximal tubules, whereas is chloride reabsorbed in the nephron?
Thick ascending LOH: Na+-K+-2Cl-
Early distal tubule: Na+-Cl- carrier
Cortical collecting ducts: HCO3- and Cl- exchange transporters & paracellular route via electrochemical gradient
Why do we believe that there is increased urinary chloride loss with Cushing’s disease?
Increased Na+ with no change in chloride gives a more
increased SID and slight increase in bicarbonate in the blood.
Due to a “more positive” vascular lumen compared to the negative urinary lumen, the body excretes more negative chloride ions to balance out the transepithelial difference.
With metabolic acidosis and a normal anion gap, would you expect chloride to be low, high or normal?
High
With metabolic acidosis and a high anion gap, would you expect chloride to be low, high or normal?
Normal
What is a strong anion?
What is the most prevalent strong anion in the the ECF?
A strong anion is an anion that completely dissociates
Chloride is the most prevalent strong anion
With a constant sodium concentration and a decrease in strong ion difference, what acid base status would that create?
Hyperchloremic metabolic acidosis
With a constant sodium concentration and an increase in strong ion difference, what acid base status would that create?
Hypochloremic metabolic alkalosis
What is the classic hypothesis for volume depletion (aka contraction) with metabolic alkalosis?
Volume depletion–>augments proximal tubular reabsorption due to decreased GFR. In proximal tubules, bicarbonate is preferentially reabsorbed as opposed to chloride and so more chloride is lost. When correcting for volume depletion, then GFR improves and more reabsorption occurs in the distal nephron where chloride is preferentially absorbed.
The chloride depletion hypothesis is an extension of this as it has been shown that chloride alone (not correcting volume status) is crucial for correcting metabolic alkalosis.
