Diuretics pt. 2 (Exam III) Flashcards
What does H₂O movement look like in the DCT?
How much Na⁺ absorption occurs in the DCT?
- ↓H₂O movement
- very little Na⁺ absorption
What ion gets reabsorbed in the DCT?
How does this occur?
Ca⁺⁺ is reabsorbed by PTH (Parathyroid hormone)
How do Thiazide diuretics elicit their effects?
Do they affect any other things?
Inhibition of NCC transporter (causing NaCl loss)
CA (Carbonic Anhydrase) inhibited slightly.
Combination of which two diuretic classes would cause a massive H₂O loss and require hospitalized monitoring?
Loop Diuretics + Thiazides
Which Thiazide diuretic is prototypical?
HCTZ (Hydrochlorothiazide)
Where is the final site of Na⁺ reabsorption?
Which site is the most important for K⁺ secretion?
Collecting Tubule
Collecting Tubule
Where do mineralcorticoids (like Aldosterone) elicit their effects?
Cortex portion of Collecting Tubule
Which channel is responsible for reabsorbing Na⁺ from the collecting tubule back into the blood?
ENaC (Epithelial Na⁺ Channel)
What potentiates the ENaC channel to increase Na⁺ retention?
Aldosterone
Where is Cl⁻ reabsorbed into the blood?
How is Cl⁻ reabsorbed into the blood?
- Collecting Tubule
1. ENaC retains Na⁺
2. Less K⁺ driven out makes urinary lumen (-)
3. (-) charge drives Cl⁻ through paracellular route into blood.
Which two diuretic classes are K⁺-wasting?
Which wastes more K⁺?
Loop Diuretics and CA Inhibitors (Acetazolamide)
Acetazolamide
Name two K⁺-sparing diuretics and their mechanism of action.
Spironolactone - blocks aldosterone receptors
Amiloride - Inhibits ENaC, blocking Na⁺ movement and thus K⁺ movement.
Rate of _____ secretion is positively correlated with aldosterone levels.
K⁺
What are the primary uses for K⁺-sparing diuretics?
States of excessive mineralcorticoids
- Conn’s Syndrome (excessive edema)
- Ectopic ACTH Production.
What are secondary uses for K-sparing diuretics?
- CHF
- Nephrotic Syndrome
