MECHANISMS OF TUBULAR SODIUM-CHLORIDE TRANSPORT

Extracellular fluid volume is determined by sodium and its accompanyin g anions. There are control mechanisms which regulate sodium balance i n the body. These include high and low pressure baroreceptors, intrare nal baroreceptors, renal autoregulation, tubuloglomerular feedback, al dosterone, and numerous other physical and hormonal factors. Sodium tr ansport by the nephron involves active and passive processes which occ ur in several different nephron segments. Mechanisms of cotransport, N a+-H+ exchange, antiporters and ion-specific channels are all. utilize d by the nephron to maintain sodium balance. These regulatory factors and transport mechanisms for sodium in the kidney will he discussed in detail.