Fig. 8. Diagram of possible secretory pathways in the ciliary processes. AA, ascorbic acid; CA carbonic anhydrase. (From Wiederholt M, Helbig H, Korbmacher C. Ion transport across the ciliary epithelium: Lessons from cultured cells and proposed role of the carbonic anhydrase. In Carbonic Anhydrase. Basel: Verlag-Chemie, 1991:232–244, with permission.)