Neuroglial cells or glial cells provide supporting functions to the nervous system. Early research viewed glial cells as the “glue” of the nervous system. However, scientists are now increasingly recognizing the pivotal role glial cells play in brain function and development.
Glial cells are smaller than neurons but are greater in number than nerve cells in the brain. Glial cells do not have axon and dendrites. However, they come into play during neural development or recovery from neural injury and during modulation of synaptic action and propagation of nerve signals.
The important CNS (central nervous system) glial cells
Astrocytes
have a star-like appearance and are involved in neuronal signaling by maintaining the right chemical environment to regulate local blood flow and enhance oxygenation.
Astrocytes also play an important role in maintaining brain homeostasis by regulating the ion concentration. In addition, astrocytes play an important role in synapse formation and function.
In sum, maintainness the environment and synapse formation / function
Microglia
(marker CD11b, CD45, Iba1, TMEM119)
As defense mechanisms, wherein the microglial cells migrate, release cytokines at the injury site, and also remove debris and dead cells by phagocytosis.
During embryogenesis in the mouse, microglia migrate from the yolk sac into the embryo through newly developed blood vessels around mid-gestation (E9.5) and begin to populate the CNS thereafter . Under non-pathogenic conditions and once the blood brain barrier closes, additional blood-borne monocytes are thought to rarely invade the CNS [2].
So, microglia is a special macrophages, which have a totally different origin to all other cells in neural system (which are neural origin). This outsider, may communicate with other outersider, like meanges and blood vessles, to regulate our brain.
Oligodendrocytes
VERY COOL SUMMERIZATION
responsible for producing the fatty substance, myelin, which acts as a protective sheath around axons thereby allowing faster travel of electrical impulses.
Radial glial cells
cannot know more
progenitor cells are multipurpose cells involved in many areas of brain developments and are precursor cells for generating oligodendrocytes, astrocytes, and neurons.
Ependymal cells
form the epithelial lining of the brain ventricles and spinal cord. Like astrocytes, ependymal cells also maintain brain homeostasis and are involved in the development of the blood-cerebrospinal fluid barrier and the blood-retina barrier.
The important PNS (peripheral nervous system) glial cells
Schwann cells, involved in myelination of neurons.
Satellite cells are small cells that surround the neurons in the sensory ganglia in the autonomic nervous system and are involved in regulation of the exterior chemical environment.
Enteric glial cells are majorly involved in regulation of the gastrointestinal system, and contribute significantly to the maintenance of the neuronal system.
