Class 11 NEET Biology Neural Control and Coordination

(b) : At the level of node of Ranvier the myelin sheath is discontinuous but not the neurilemma lining. Actually myelin sheath is an integral part of Schwann cell - which form a continuous neurilemmal covering. Each Schwann cell wrap-around the neurite to form concentric layers of plasma membrane. But at the level of junction between two Schwann cells myelin cannot be formed and thus a gap appears.