Magnesium Flashcards
over 60% of mg in the body is located in the____
25% is located in the___
bones
muscle
sources
nuts seeds, legumes, whole grains, corn, carrots, black strap molasses, dairy, chocolate, cocoa, tea, coffee
magnesium is absorbed in the ____
small intestine (primarily in the distal jejunum and ileum)
magnesium can be absorbed by ___ pathways
2
a saturable carrier mediated active traansporter helps absorb magnesium when intake is ___, this route is stimulated by____
low
vitamin D
passive diffusion helps absorb magnesium when intake is___
highe
factors that enhance magnesium absorption
vitamin d
simple sugars
factors that inhibit magnesium absorption
phytates
fiber
excesive unabsorbed fatty acids
minerals- Ca and K
magnesium is transported in the blood in what three forms
free ionized
bound to protein
complexed with other ions
PTH _____ plasma concentration of Mg
increases
how does PTH increase plasma concentrations of Mg
increases intestinal absorption
decreases renal excretion
enhances bone resorption
functions of magnesium
energy production
structural role
ion transport across membranes
cell signalling
magnesium participates as a cofactor in all aspects of energy metabolism including
glycolysis
beta-oxidation
TCA cycle
____exists primarily as a complex with Mg
ATP
60% of the magnesium in the body is associated with ___ and ___ as part of the bone crystal matrix
calcium
phosphorous
magnesium is required for the active transport of ions including ____ and ____ across cell membranes
potassium
calcium
magnesium affects the conduction of
nerve impulses
muscle contraction
blood vessel dilation
normal heart rhythm
cell signaling requires Mg-ATP for the phosphorylation of proeins and the formation of the cell signaling molecule _____
cAMP
cAMP is involved in the secretion of ___ from the parathyroid gland
PTH
Mg is excreted primarily in the
urine and feces
True or False, magnesium cannot be lost in perspiration
False
conditions increase the risk of magnesium deficiency
malabsorption syndromes
renal disorders
chronic alcoholism
elderly
S&S of deficiency
hypomagnesemia hypocalcemia, hypokalemia retention of Na low PTH mm tremor, spasm, cramps, tetany chest tightness, SOB palp and cardiac arrhyth loss of appetite, n/v anxiety, panic, depression, fatigue, insomnia
clinical indications for Mg supplementation
hypertension
migraine headaches
_____ is a relatively common dose-related side effect of Mg supplementation
diarrhea
individuals with _____ are at higher risk for adverse effects from excess supplemental mg intake
renal impairment
hypermagnesemia results in_____
hypotension
severe hypermagnesemia may result in _____
cardiac arrest
CI of Mg
hypermagenesemia end stage renal dz myasthenia gravis UTI * caution with hyperparathyroidsism
high ___ intake may decrease tissue levels of mg
calcium
magnesium is needed for ____ secretion
PTH
high levels of ____ inhibit release of PTH
Mg
hydroxylation of _____ in the liver requires Mg
Vit D
magnesium is essential for the cellular uptake of ___ from the blood
potassium
high doses of ____ in supplemental form interfere with the absorption of mg
zinc
____ increases the cellular uptake of MG
vitamin b6
large doses of ____ may increase the need for magnesium
thiamine
