Neuroglial Cells

 What are neuroglial cells?

Besides neurons, the other type of cells present in nervous system are glial  or neuroglial cells.These cells form myelin, protect and support neurons.They are far more numerous than neurons (approximately 10 times more than neurons).

What are  the functions of neuroglial cells?

Following are the functions of neuroglial cells:

• Provide structural support to neurons.
• They Form myelin sheath.
• Participate in formation of blood – brain barrier.
• Phagoctytosis.
• Produce cerebrospinal fluid.

Name the various neuroglial cells.

A. Neuroglia in Central nervous system (CNS)

1. Asrtocytes

• They are the largest glial cells.
• They are star-shaped cells with many processes.
• The ends of the processes are called foot processes which cover the capillaries to form blood – brain barrier.
• Function: They also provide structural support to the neurons.
• Astrocytes are of two types:
  • Protoplasmic astrocytes:  They are found in gray matter.
  • Fibrous astrocytes: They are found in white matter.

2. Oligodendrocytes

• They are smaller than astrocytes and have fewer processes. 
• Function:They form myelin around the axons in CNS.

3. Microglia

• These are the smallest glial cells.
• Function: They phagocytose  the pathogens and cell debris within the CNS.

4. Ependymal cells

• They line the ventricles of brain and central canal of spinal cord.
• Function: They produce cerebrospinal fluid.

B. Neuroglia in peripheral  nervous system (PNS)

1. Schwann cells

• Surround the axons of peripheral nerves.
• Function: They form myelin sheath  around the axons around the nerve fibers of peripheral nervous system.

2. Satellite(capsular) cells

• They surround the cell bodies of neurons in the autonomic and sensory ganglia.
• Function: They provide  structural support  to the neurons in the ganglia.

All neuroglial cells develop from neural crest  except microglia which develops from mesoderm.

Applied Aspects