Reg of K+, Ca+, Pi, and Mg+ Balance DSA Flashcards
Normal Range of K+
3.5-5 mEq/L
Hyper and Hypokalemia values
<3.7 mEq/L===> Hypokalemia
> 5.2 mEq/L==> Hyperkalemia
Cardiac Effects to K+ levels
Cardiac conduction system responds in opposite directions to hyperkalemia. The K+ channels increase their conductance enough that their membrane can become hyperpolarized and less likely to fire
Hyper=bradycardia
Hypo=tachy
Low T-waves with hypo and tall, peaked T-waves with hyperkalemia
Normal Range of Ca2+
1000mg/day for adults
Plasma level: 5.0 mEq/L
Hypo and Hypercalcemia
Hypocalcemia= Increases neuromuscular excitability
-Hypocalcemic tetany/spasticity
Hypercalcemia= Depresses neuromuscular excitability
-Threshold shifts away from resting membrane potential
Calcium regulators
PTH-Increases blood Ca2+ levels
Calcitonin- Deceases blood Ca2+ levels
Calcitriol- Hormonally active form of vit D, increases blood Ca2+ levels by increasing ability of Ca2+ absorption from gut
Known regulators of Pi metabolism
1) Dietary phosphate intake and absorption
2) Calcitriol- increases phosphorous resorption from bone and absorption from intestine
3) PTH- phosphorous resorption directly from bone, and indirectly activates intestinal absorption thru stimulation of calictriol production
4) Renal tubular reabsorption of phosphorous, which is stimulated by tubular filtered load of phosphorous and inhibited by PTH
Phosphate storage in the Body
85% in bones
14% in cells
1% in serum
1500 mg intake of phos per day
Mg in the body
Involved in almost every biochemical process int he cell
Nucleotide binding, cofactors, glycolysis, proliferation
Mg2+ depletion associated with migraine, depression, epilepsy, SIDS, arrhythmia, preeclampsia, muscle cramps
50% in bone
49% in ICF (especially muscle)
1% in ECF
Serum Mg2+ =1.8 mEq/L
Free serum = 0.8-1.0 mEq/L
