Which part of the neuron is not found in CNS cells?

• A. Axon
• B. Dendrites
• C. Neurilemma
• D. Myelin sheath

Answer: (C)

The correct answer is the neurilemma, which is not found in central nervous system (CNS) neurons. The neurilemma, or the outer membrane of Schwann cells, is specific to the peripheral nervous system (PNS). In the PNS, Schwann cells wrap around axons to form the myelin sheath, providing insulation and support, as well as forming the neurilemma that plays a crucial role in the regeneration of injured axons.

In contrast, neurons in the CNS have a different type of myelin sheath formed by oligodendrocytes, which do not form a distinct outer covering like the neurilemma. Therefore, while axons and dendrites are fundamental components of both CNS and PNS neurons, the presence of the neurilemma is exclusive to neurons in the peripheral nervous system. This distinction is important in understanding neuronal structure and function in different parts of the nervous system.