Rapid Review of Glial Cells

Introduction

• Purpose: Address frequent questions about glial cells.
• Goal: Ensure understanding of glial cells to avoid mistakes in identifying them.

Types of Glial Cells

1. Astrocytes

   • Appearance: Star-like cells.
   • Functions:
     • Maintain proper extracellular environment in CNS.
     • Supportive role in the brain.
     • Maintain the blood-brain barrier.
     • Involved in reactive gliosis (changes after brain injury).
   • Identification:
     • Presence of GFAP (memorize astrocytes = GFAP).
     • Most abundant cell in the brain.
     • Communicate via gap junctions.
   • Mnemonic: Astro = Star (stars of the extracellular environment).

2. Microglia

   • Appearance: Tiny cells (micro = small).
   • Functions:
     • Phagocytosis in CNS (brain's macrophages).
     • Active in reactive gliosis after injury.
     • Form reactive oxygen species (ROS).
     • Implicated in neurodegenerative conditions (e.g., ALS).
   • Origin: Derived from the mesoderm.
   • Mnemonic: Micro = Small (CNS macrophages).

3. Oligodendrocytes vs. Schwann Cells

   • Shared Function: Myelin formation.
   • Oligodendrocytes:
     • Location: Central nervous system (CNS).
     • Origin: Derived from neuroectoderm.
     • Pathology: Damaged in leukodystrophies.
     • Appearance: "Fried egg" under a microscope.
     • Mnemonic: All Eggo dendrocytes (fried egg appearance).
   • Schwann Cells:
     • Location: Peripheral nervous system (PNS).
     • Origin: Derived from neural crest.
     • Mnemonic: Schwann's Crest (Schwann cells from neural crest).

4. Ependymal Cells

   • Function: Involved in CSF regulation.
   • Appearance: Line the ventricles, can be simple columnar or cuboidal.
   • Features: Apical surface with cilia and microvilli.
   • Mnemonic: CSF depends on ependymal (epend = depends).

Conclusion

• Summary Table: Not included but remember key mnemonics for each cell type.
• Encouragement: Hope the review was helpful and aids in academic success.