Neuroglia; glial cell
The neurons of the central nervous system are supported by the four types of non-excitable glial cell a quarter to a half the volume of brain tissue.
Four types of neuroglia found in cental nervous system are-
1. Astrocytes
2. Oligodendrocytes
3. Microglial cell
4. Ependymal cells
1. Astrocytes
Astrocytes cell form the main supporting tissue of CNS.
They star shape with fine processes and they lie in the mucopolysaccharides ground substances.
They are found or built in large adjustment to blood vessels, highway for migrating neurons.
Blood is separated from neurons by capillary walls and the layer of astrocytes and maintain blood brain barrier.
Blood brain barrier (BBB) is selective barrier that protect the brain from toxic substance in blood. For example; CO2, alcohol, ammonia level, any kind of chemical drug, urea, uric acid.
2. Oligodendrocytes
These are smaller than astrocytes. They form and maintain myelin sheath.around axon.
Give support to neurons in CNS.
Provide supportive framework, supplies nutrition for neuron.
3. Microglial cell
They are derived from monocytes. They are found mainly in the area blood vessels and they function as phagocytic cells are remove microbes and damage tissues in area of inflammation and cell destruction.
4. Ependymal cell
These cells form the epithelial lining of the ventricles of brain, and central canal of spinal cord and also help secretion and circulation of CSF.
0 Comments