Anions and Cations Flashcards
(41 cards)
Acidemia results in what type of movement of K+?
From the ICF to the ECF
H+ ions are brought into the cell and exchanged for K+ ions
Alkalemia results in what type of movement of K+?
From the ECF to ICF
H+ ions are pushed out into the ECF; in exchange for K+ ions
What cells are primarily excreting K+ and reabsorbing K+ based on plasma levels?
K+ Reasborption: A-intercalated Cells
K+ Secretion: Principle cells
What is primary potential along the tubular lumen of the Collecting Duct?
Negative; - 50 mV
What are the characteristics and underlying etiology of Conn’s disease?
Conn’s Disease (Primary hyperaldosteronism)
- Aldosterone secreting tumor in the adrenal cortex
- K+ secretion in the collecting duct is innapropriately stimulated
- Consequence: Hypokalemia
What are the characteristics and underlying etiology of Addison’s Disease?
Addison’s Disease: Hypoaldosteronism
- Desctruction of Adrenal glands; aldosterone isn’t secreted
- Decreased K+ secretion in collecting duct
- Consequence: Hyperkalemia
What is the action of Osmotic Diuretics?
- Inhibit water reabsorption, and Na+, secondarily.
- Increased osmolarity of tubular fluid
- Act @ PCT
What is the action of Carbonic Anyhydrase inhibitors?
- Inhibit NaHCO3- reabsorption
- Can cause metabolic acidosis
- Act @ pCT
What is the action of loop diuretics?
- Inhibits Na+,K+, 2 Cl- cotransporter
- Increases RBF & decreased concentration of medullary intersitium
- Lessens water reabsorption at descending limb of Loop
- Acts @ Loop of Henle (20-25% of Na+ reabsorption)
What is the action of thiazide diuretics?
- Inhibit Na+/Cl- contransporter
- Increases Na+ secretion (primarily) and K+ secretion (secondarily)
- Decreased Ca2+ excretion
- Acts @ DCT
What is the action of K+ sparing diuretics?
- Inhibits Na+ reabsorption & K+ secretion
What is the concept of diuretic breaking?
- Chronic use of diuretics can lead to adaption of the distal sites to reabsorption the increased solute concentrations.
- Requires individuals take K+ supplements to prevent K+ wasting
What is the approximate % of total calcium that is filtered into Bowman’s capsule?
~ 55%
Where is the bulk of filtered Mg2+ reabsorbed?
It is reabsorbed via paracellular movement in the TAL; driving force is the positive transepithelial potential
What effect does insulin have on K+ regulation?
Also, what does diabetes mellitus cause in regards to K+?
1) It increases activity of Na+/K+ ATPase on the basolateral membrane of the principal cells; stimulating uptake of K+ into the cells
2) Associted with Hypokalemia
What do agonists of B2 adrengeric receptors cause in regards to K+?
They stimulate Na+/K+ ATPase; causing hypokalemia
What do agonists of A1 adrenergic receptors cause in regards to K+ reabsorption?
1) They cause shift of K+ out of the interstitum and into the pertibular capillary; causing Hyperkalemia
Where is Phosphate primarily reabsorbed?
PCT; via Na+/Phosphate cotransporter
What is the effect of PTH on Ca2+?
It increases its reabsorption of Ca2+ at the distal tubule, ; stimulating adenyl cyclase and cAMP, it also stimulates the production of Vit D3 (Calcitriol)
What is the effect of PTH on Phosphate?
It inhibits its reabsorption via; antagonist, of Na+/Phosphate cotransporter at the PCT
What two markers would be elevated as a result of increased PTH levels?
cAMP & Phosphaturia
What is Pseudohypoparathyroidism?
Defects in PTH’s receptor; Gs protein and Adenyl Cyclase –> Result: Renal cells are resistant to PTH
What are the main sites of Ca2+ reabsorption in the nephron?
1) Passive process; tightly coupled to Na+ reabsorption in the PCT and TAL
What classes of diuretics can treat hypercalciuria and hypercalcemia; respectively?
1) Treat Hypercalciuria: Increase reabsorption of Ca2+ –> Thiazide diuretics
2) Treat Hypercalcemia: Increase secretion of Ca2+ –> Loop diuretics
