What is the significance of microglial cells?

Explanation

**Step-by-Step Solution:**

1. **Definition of Microglial Cells**: Microglial cells are specialized cells that are part of the immune system in the central nervous system (CNS). They can be considered a population of macrophages that reside in the CNS.

2. **Origin of Microglial Cells**: These cells are derived from the mesodermal layer during embryonic development, which is one of the three primary germ layers.

3. **Physical Characteristics**: Microglial cells are the smallest glial cells in the CNS and have unique feathery processes that extend from their cell bodies.

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