effector. Definitions: 1. As defined by Sherrington, a peripheral tissue that receives nerve impulses and reacts by muscular contractioon, glandular secretion, or electric discharge (from an electric organ, as in the case of certain bony fishes such as the electric eel).2.. As defined by Sherrington, a peripheral tissue that receives nerve impulses and reacts by muscular contractioon, glandular secretion, or electric discharge (from an electric organ, as in the case of certain bony fishes such as the electric eel).