define glial cells , microglial cells. , & astrocytes _?

Please refer the links below:-
https://www.meritnation.com/ask-answer/question/what-are-glial-cells/tissues/3019403

https://www.meritnation.com/ask-answer/question/astrocytes-presumably-separate-and-provide-mechanical-stren/neural-control-and-coordination/8070495

Kindly post rest of your queries in separate thread.