William Orville Douglas was the-longest serving member of  the Court, with a tenure of 36 years, 209 days. He was appointed by  President Roosevelt in 1939 and retired in 19â¦75. He was also known  to be a member of the Democratic Party.
Major Electrolytes Located Outside the Cell (Extracellular) Sodium and Calcium Sodium is a major electrolyte in extracellular fluid and it exercises most of its influence outside the cell. The concentration of sodium affects serum osmolality (solute concentration in 1 L of water) and extracellular fluid volume. Sodium also assists nerves and muscle cells to interact.
The serum electrolytes include: 1  Sodium (Na). 2  A positively charged electrolyte that helps to balance fluid levels in the body and facilitates neuromuscular functioning. 3  Potassium (K). 4  A main component of cellular fluid, this positive electrolyte helps to regulate neuromuscular function and osmotic pressure. 5  Calcium (Ca).he serum electrolytes include: 1  Sodium (Na). 2  A positively charged electrolyte that helps to balance fluid levels in the body and facilitates neuromuscular functioning. 3  Potassium (K). 4  A main component of cellular fluid, this positive electrolyte helps to regulate neuromuscular function and osmotic pressure. 5  Calcium (Ca).