摘要: The kidneys filter about 180 L of plasma daily. Most this must be reclaimed in order to maintain fluid and electrolyte homeostasis. protein-free ultrafiltrate is modified composition as it passes through various segments the nephron form urine. Sodium (Na+) its anion chloride (Cl−) are major determinants extracellular (ECF) volume, both ions effectively reabsorbed. Water reabsorption follows Na+ normal osmolality ECF compartment. proximal tubule site reclamation, whereas other reclaim a variable degree.