Calcium channel blocker effect is maximum on

Ans: b (Smooth muscle)Ref: Ganong, 21st edi., Pg. 70-84Ca influx in smooth muscle is mainly via Ca channels unlike skeletal and cardiac muscle where most of the calcium comes from sarcoplasmic reticulum.This is the reason why after taking calcium channel blockers there is on smooth muscle relaxation (arterial vessel) rather than skeletal and cardiac muscle.Summary of smooth muscle contractionAction potential causes release of stored Ca which thenbinds to calmodulin and activates the calmodulin dependentmyosin light chain kinase.It phosphorylates myosin. Phosphorylation of myosin is essential for contraction.In smooth muscles, troponin is not required for contraction.