**Question:** In cell death, myelin bodies are derived from

A. Schwann cells in peripheral nerves
B. Oligodendrocytes in central nervous system
C. Neurons
D. Ependymal cells in the central nervous system

**Correct Answer:** B. Oligodendrocytes in the central nervous system

**Core Concept:** Myelin is a fatty substance that surrounds and insulates nerve fibers, allowing for rapid transmission of electrical impulses. In the central nervous system (CNS), myelin is formed by a group of glial cells called oligodendrocytes. Myelin bodies, also known as myelin sheaths, play a crucial role in maintaining the integrity and efficiency of nerve impulse conduction.

**Why the Correct Answer is Right:** Oligodendrocytes are specialized glial cells responsible for the production of myelin in the CNS. They form myelin sheaths around axons, which enhances the conduction velocity of nerve impulses. In contrast, myelin in the peripheral nervous system (PNS) is produced by Schwann cells, not oligodendrocytes.

**Why Each Wrong Option is Incorrect:**

A. Schwann cells in the PNS: These cells are responsible for producing myelin in the peripheral nervous system, not the central nervous system. In the CNS, myelin is produced by oligodendrocytes.

B. Ependymal cells in the central nervous system (incorrect): Ependymal cells are a type of glial cell that lines the ventricles of the brain and spinal cord. They do not produce myelin bodies.

C. Neurons: Neurons are the functional units of the nervous system, transmitting signals throughout the body. They are not the source of myelin bodies.

**Clinical Pearl:** Understanding the differences between oligodendrocytes and Schwann cells is crucial for understanding the diverse functions of these cells in the nervous system. Myelin production and myelin sheath formation are specific functions of oligodendrocytes in the CNS, while Schwann cells in the PNS carry out these tasks in the peripheral nervous system.