Figure 6

Suggested model for ion transport mechanisms in the cells of the vertebrate primary ureter. A Na⁺-K⁺-ATPase in the basolateral cell membrane pumps Na⁺ out of the cell and thereby provides the driving force for apical uptake of Na⁺ through channels. K⁺ is secreted across the apical cell membrane through channels and recycled for the pump across the basolateral cell membrane.