Intro to K, Ca, Mg, and P balance Flashcards
What is the distribution of Potassium in the body?
98% intracellular
80% muscle cells (about 150mEq/L)
20% liver, bone, and erythrocytes
2% extracellular
What causes Hyperkalemia?
Excess intake of K+
Excess tissue release
Rhabomyolysis, burns, hemolysis
Shifts from ICF to ECF
Hyperglycemia, acidosis, insulin deficiency, tissue damage,
What causes Hypokalemia?
Vomiting, insulin excess, deficiency, alkalosis
How does hyperkalemia cause bradycardia?
K channels increase their conductance enough that the membrane becomes hyperpolarized and less likely to fire.
How does low plasma K effect pH?
Causes cell acidosis
A high plasma K concentration has what effect on the vasculature?
Causes vasoconstriction
What factors enhance K uptake?
B-catecholamine
Alkalosis
Insulin
What factors impair K uptake?
A-Catecholamine
Acidosis
Cell Damage
What role does calcitriol have in calcium and phosphorus distribution?
Absorption from the GI
Resorption from bone
Inhibits kidney secretion (of Calcium)
How does hypocalcemia effect neuromuscular activity?
Increases neuromuscular activivity causing hypocalcemic tetany / spasticity.
What is the body distribution of phosphorous?
85% = bone
14% = cells
1% = serum
What does PTH cause?
Resorption of phosphorus and Calcium from bone.
Stimulates calcitriol release.
Stimulates secretion of Phosphorous
What is Mg2+ depletion associated with?
Migraine, depression, epilepsy, arrhythmia, preclampsia, and muscle cramps.
Describe the distribution of Mg2+ in the body?
50% in bone
49% in ICF (especially in muscle)
1% in ECF
What clinical correlations are made to low serum calcium?
Hypoparathyroidism
Renal disease
Vitamen D deficiency
