Question

20 which of the following cells is found only in the pns? multiple choice microglial cell (other options partially visible)

Explanation:

To solve this, we analyze each option:

1. Microglial cell: These are found in the central nervous system (CNS), acting as immune cells there. Eliminate this.
2. Astrocyte: Astrocytes are a type of glial cell in the CNS, involved in support and regulation. Eliminate this.
3. Ependymal cell: These line the ventricles of the brain (CNS) and produce cerebrospinal fluid. Eliminate this.
4. Schwann cell: Schwann cells are glial cells that myelinate axons only in the peripheral nervous system (PNS).

• Microglial, astrocyte, and ependymal cells are CNS - specific.
• Schwann cells myelinate PNS axons, so they exist only in the PNS.

Answer:

Schwann cell (assuming the last option is "Schwann cell" from typical versions of this question)