Which of these is NOT a part of the structure of a typical neuron?

The story behind the answer

Islets of Langerhans are not parts of neurons—they’re clusters of endocrine cells in the pancreas that secrete hormones like insulin and glucagon to regulate blood glucose. In contrast, Schwann cells, the myelin sheath, and Nodes of Ranvier are all key features of peripheral neurons: Schwann cells wrap axons to form the insulating myelin sheath, and the Nodes of Ranvier are the gaps between myelinated segments where action potentials “jump,” speeding nerve conduction.

Memory tip: “Islets → Insulin → Pancreas,” not nerves. Also remember that in the central nervous system, oligodendrocytes (not Schwann cells) make myelin. Knowing these roles helps link structure to function: insulation (myelin), makers of insulation (Schwann cells), and the “jump points” (nodes) that enable rapid, saltatory signal transmission.