25. Potassium shifts Flashcards Preview

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Flashcards in 25. Potassium shifts Deck (10):
1

factors that shift K+ out of cells ( causing hyperkalemia)

1. digitalis ( blocks Na+/ K+ ATPase)
2. Hyperosmolarity
3. Cell lysis ( crush injury, tumor lysis syndrome, rhabdomyolysis )
4. Acidosis
5. β-blocker
6. insulin deficiency
7. exercise

2

β- blocker causes hyperkalemia - mechanism

1. Beta blockers suppress catecholamine - stimulated renin release, thereby decreasing aldosterone synthesis
2. nonselective beta blockers decrease cellular uptake of potassium

3

acidosis causes hyperkalemia - mechanism

exchange of extracellular H+ for intracellular K+

4

hyperosmolarity causes hyperkalemia - mechanism

H2O flows out of the cell --> K+ diffueses out with H2O

5

Cell lysis causes hyperkalemia - examples (3)

1. crush injury
2. tumor lysis syndrome
3. rhadmomyolysis

6

factors that shift K+ into cells ( causing hypokalemia )

1. hyposmolarity
2. alkalosis
3. β- adrenergic agonist ( increase Na+/K+ ATPase)
4. insulin ( increase Na+/ K+ ATPase)

7

alkalosis causes hypokalemia - mechanism

exchange of intracellular H+ for extracellular K+

8

insulin shifts K+ into cells - mmechanism

increase Na+/ K+ Atpase

9

β- adrenergic agonist shifts K+ into cells - mechanism

increase Na+/ K+ Atpase

10

hypoosmolarity shifts K+ into cell - mechanism

H2O flow into the cell, K+ diffuse with H2O

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