NEURAGLIA_STRUCTURE_FUNCTION_LOCATION_BRAIN

NEURAGLIA
Dr. E. Muralinath, Dr. M. Guruprasad, Dr. K.
Sravani Pragna, Dr. C. Kalyan, Dr. P. Manjari, Dr. D.
Kusumalatha, Dr. K. Sridevi , Dr. Ch. Ramya Sudha
and R. Gnana Lahari

• DEFINITION
• Neuroglia or glia (glia = glue) is the supporting cell of the nervous system.
• Neuroglial cells are non-excitable and do not exhibit the property of transmission of nerve impulse
(action potential).
• So, these cells are also termed as non-neural cells or glial cells.
• If compared to the number of neurons, the number of glial cells is 10 to 15 times greater.
5)Neuroglial cells play an important role particularly regarding the reaction of nerve during
• infection.
• 6)Most commonly, neuroglial cells establish the site of tumors in nervous system.

• CLASSIFICATION OF NEUROGLIAL CELLS
• The distribution of neuroglial cells takes place in central nervous system (CNS) as well as
peripheral nervous system (PNS). Accordingly the neuroglial cells are categorized
• into two types:
• A. Central neuroglial cells
• B. Peripheral neuroglial cells.
• CENTRAL NEUROGLIAL CELLS
• Neuroglial cells in CNS are categorized into three types:
• Astrocytes
• Microglia
• Oligodendrocytes

• Astrocytes:-
• Astrocytes are star shaped neuroglial cells observed in all parts of the brain.
• Two varities of astrocytes are observed in humam brain such as fibrous astrocytes and protoplasmic
astrocytes.
• Functions of Astrocytes
• Astrocytes:
• i. Twist around the nerve cells and arrange the supporting network especially in brain and spinal cord
• ii. Form the blood-brain barrier and thereby control the entry of substances from blood into
• brain tissues .
• iii. Maintain the chemical environment of ECF around CNS neurons
• iv. Provide calcium and potassium and control neurotransmitter level in synapses
• v. Control recycling of neurotransmitter especially synaptic transmission.

• MICROGLIA
• Microglia are the smallest neuroglial cells.
• These cells are derived from monocytes and gain an entry into the tissues of nervous system
especially from blood.
• These phagocytic cells migrate to the site of infection or injury and are often treated as the
macrophages of CNS.
• Functions of Microglia
• Microglia:
• i. Engulf and destroy the microorganisms and cellular debris with the help of phagocytosis
• ii. Migrate to the injured or infected

• OLIGODENDROCYTES
• Oligodendrocytes are the neuroglial cells, which produce myelin sheath particularly around the
nerve fibers in CNS. Oligodentrocytes are also termed as oligodendroglia.
• Oligodendrocytes consist of only few processes.
• Functions of Oligodendrocytes
• Oligodendrocytes:
• i. Arrange myelination around the nerve fibers particularly in CNS where Schwann cells are
absent
• ii. Arrange support to the CNS neurons by forming a semi-stiff connective tissue especially
between the neurons.
•

• PERIPHERAL NEUROGLIAL CELLS
• Neuroglial cells in PNS are categorized into two types:
• 1. Schwann cells
• 2. Satellite cells.
• SCHWANN CELLS
• Schwann cells are the major glial cells in PNS .
• Functions of Schwann Cells
• Schwann cells:
• i. Arrange myelination (insulation) particularly around the nerve fibers in PNS
• ii. Play important role regarding nerve regeneration
• iii. Eliminate cellular debris especially during regeneration with the help of their phagocytic activity.

• SATELLITE CELLS
• Satellite cells are the glial cells observed on the exterior surface of PNS neurons.
• Functions of Satellite Cells
• Satellite cells:
• i. Arrange physical support to the PNS neurons
• ii. Plays an important role regarding the regulation of chemical environment of ECF around the
PNS neurons.

References
• 1.
• Autilio-Gambetti L, Sipple J, Sudilovsky O, Gambetti P. Intermediate filaments of Schwann cells. J Neurochem. 1982 Mar;38(3):774-80. [PubMed]
• 2.
• Takamori Y, Mori T, Wakabayashi T, Nagasaka Y, Matsuzaki T, Yamada H. Nestin-positive microglia in adult rat cerebral cortex. Brain Res. 2009
May 13;1270:10-8. [PubMed]
• 3.
• Graeber MB, Streit WJ, Kreutzberg GW. The microglial cytoskeleton: vimentin is localized within activated cells in situ. J Neurocytol. 1988
Aug;17(4):573-80. [PubMed]
• 4.
• Stolt CC, Schlierf A, Lommes P, Hillgärtner S, Werner T, Kosian T, Sock E, Kessaris N, Richardson WD, Lefebvre V, Wegner M. SoxD proteins
influence multiple stages of oligodendrocyte development and modulate SoxE protein function. Dev Cell. 2006 Nov;11(5):697-709. [PubMed]
• 5.
• Dotiwala AK, McCausland C, Samra NS. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Apr 4, 2023. Anatomy, Head and Neck:
Blood Brain Barrier. [PubMed]
• 6.
• Voet S, Prinz M, van Loo G. Microglia in Central Nervous System Inflammation and Multiple Sclerosis Pathology. Trends Mol Med. 2019
Feb;25(2):112-123. [PubMed]
• 7.
• Del Bigio MR. The ependyma: a protective barrier between brain and cerebrospinal fluid. Glia. 1995 May;14(1):1-13. [PubMed]

• 8.
• Benveniste EN. Role of macrophages/microglia in multiple sclerosis and experimental
allergic encephalomyelitis. J Mol Med (Berl). 1997 Mar;75(3):165-73. [PubMed]
• 9.
• Turner MR, Cagnin A, Turkheimer FE, Miller CC, Shaw CE, Brooks DJ, Leigh PN, Banati RB.
Evidence of widespread cerebral microglial activation in amyotrophic lateral sclerosis: an
[11C](R)-PK11195 positron emission tomography study. Neurobiol Dis. 2004 Apr;15(3):601-9. [
PubMed]
• 10.
• Yiangou Y, Facer P, Durrenberger P, Chessell IP, Naylor A, Bountra C, Banati RR, Anand P.
COX-2, CB2 and P2X7-immunoreactivities are increased in activated microglial
cells/macrophages of multiple sclerosis and amyotrophic lateral sclerosis spinal cord. BMC
Neurol. 2006 Mar 02;6:12. [PMC free article] [PubMed]

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