Major current for depolarization in Purkinje fiber is of:: (A) Na+, (B) Ca++, (C) K+, (D) Cl-
Answer is A. Purkinje fiber is a fast-response type or rapidly depolarizing fiber. The rapid depolarization is due a rapid influx of Na+ through the fast Na+ channels. Major current for depolarization in pacemaker cells is due to Ca++