Sodium
Abbreviation:
Na
+Definition:
The main cation (positively charged ion) of the extracellular fluid.
Sodium (Na
+) plays an important role in several physiological processes such as the
action potential of neurons and muscle cells,
secondary active, sodium-coupled transport of ions, nutrients, neurotransmitters across the plasma membrane of cells, and many other processes.
The extracellular concentration of Na
+ is about 145 mM. The intracellular concentration of Na
+ is about 15 mM.
Posted: Wednesday, February 5, 2014
Last updated: Wednesday, March 12, 2025