MAGNESIUM Flashcards
4th most abundant [?] in the body
After
cation
Na, K, Ca
2nd most abundant [?]
After[?]
intracellular ion
K
Amount in the body:
24g
distributed in primarily in the:
bones (53%)
intracellularly (46%)
bound to ATP (80%)
extracellularly (<1%)
serum magnesium (extracellular) is further divided into:
protein bound (30%)
ionized or free (55%) - readily available
complexed with other molecules such as phosphate and citrate (15%)
bones
(53%)
intracellularly
(46%)
bound to ATP
(80%)
extracellularly
(<1%)
protein bound
(30%)
ionized or free - readily available
(55%)
complexed with other molecules such as phosphate and citrate
(15%)
– most commonly used cofactor
Magnesium
Cofactor for
> 300 enzymes
Cofactor for > 300 enzymes, including those involved in:
- Glycolysis – breakdown of glucose
- Neuromuscular transmission
- Synthesis of CHO, CHON, lipids & nucleic acids
- Release of and response to certain hormones
[?] of dietary magnesium is absorbed in the [?]
20 to 65%
small intestines
overall regulation like the other electrolytes is a responsibility of the
kidney
Non-protein bound magnesium is readily filtered by the [?]
glomerulus
25 to 30% is reabsorbed in the
proximal convoluted tubules
Majority: 50 to 60% in the [?].
ascending loop of Henle
Only 2 to 5% is reabsorbed in the [?].
distal convoluted tubules
The renal threshold of magnesium is
0.60 to 0.85 mmol/L or mEq/l
Normal serum conc:
Approximately [?]of filtered magnesium is excreted in the urine per day.
6%
Related To The Regulation Of
Calcium And Sodium
increases the renal reabsorption of magnesium
PTH
enhances absorption of magnesium in the small intestines
PTH
provides the opposite effects
aldosterone and thyroxine
– overproduction of the PTH; abnormal inc of Mg conc in the blood; fast metabolism
primary hyperparathyroidism
steroid hormone
aldosterone
