Macrophage in CNS -

Ans. is 'b' i.e., Microglia MicrogliaQo As the name suggests, they are small sized glial cells. They are phagocytic in function0. They are mesodermal in origin0 and are derived from circulating monocytesQ. Therefore, they originate in bone marrow, important microglia celts are Gitter cells, Rod cells and Siderophages.o Neuroglial cells are equivalent of connective tissue cells in CNS. There are following type of neuroglial cells : -Macroglia# These are the main glial cells of CNS. These are derived from neuroectodermQ. There are three major types of macroglia: -AstrocytesQ : - As their name indicates, astrocytes are star shaped. There are two types of astrocytes Protoplasmic and fibrous type. Protoplasmic astrocytes are found in grey matterQ, whereas fibrous astrocytes are found in white matter: Astrocytes has following functions : -i) Repair and scar formation in CNSii) Through their processes and footplates on the wall of blood vessels, they help to the formation ofBBB.iii) Astrocytes store glycogenThey clear the neural tissues of excess K~ and neurotransmitters that accumulate extracellularly following neural activity.They form isolation around synapses so as to prevent chaotic spread of nerve impulses.OligodendrocytesQ: - They are responsible for myelination around axons in the CNSQ (In peripheral nervous system, this function is served by Schwann cells).Ependymal cells : - These cells form the lining of ventricles.MicrogliaQo As the name suggests, they are small sized glial cells. They are phagocytic in functionQ. They are mesodermal in originQ and are derived from circulating monocytesQ. Therefore, they originate in bone marrow. Important microglia cells are Gitter cells, Rod cells andSiderophages.