Question
Plasma magnesium levels are maintained by
| A. |
Renal reabsorption |
| B. |
GIT absorption |
| C. |
Bone resorption |
| D. |
Diet |
Show Answer
|
Correct Answer � A Explanation |
 |
– The kidney is the primary regulator of plasma magnesium.
– ~70% of filtered magnesium is reabsorbed in the thick ascending limb of Henle’s loop.
– The distal convoluted tubule fine-tunes final magnesium reabsorption.
– Gastrointestinal (GIT) absorption & bone stores affect total magnesium but don’t acutely regulate plasma levels.
– Dietary intake provides magnesium, but excess is excreted; renal handling maintains steady plasma levels.