Final answer:
The maintenance of normal intracellular fluid volume is largely dependent on the intracellular concentration of potassium (K+) ions. Potassium is crucial for cellular functions and is actively transported into cells by the sodium-potassium pump. Chloride ions, while abundant in the ECF, are less influential on the ICF volume.
Step-by-step explanation:
Maintenance of normal intracellular fluid volume depends largely on the intracellular concentration of potassium ions.
Intracellular fluid (ICF) is characterized by high concentrations of potassium (K+), which are about 30 times higher inside than outside of cells. This uneven distribution is critical for various cellular functions, including establishing the resting membrane potential in neurons and muscle fibers. The sodium-potassium pumps in cell membranes play a pivotal role in maintaining this concentration gradient by actively transporting potassium into the cell against its concentration gradient. Extracellular fluid (ECF), on the other hand, has a higher sodium concentration with sodium ions being about 10 times higher outside than inside of cells.
The balance of cations and anions is crucial for retaining the electrical neutrality of the fluids. While chloride is the predominant extracellular anion, helping to maintain the osmotic pressure gradient between the ICF and ECF, potassium ions are the major intracellular cations with significant physiological functions. The recommended daily intake of potassium is 4700 mg, which is managed through dietary consumption and regulated by exchange systems in the body, especially the kidneys.