Changes

==Microglial Cells==

==Microglial Cells==

[[Image:microglia.jpg|thumb|right|150px|Microglia (immunohistochemical staining.) Grzegorz Wicher, '''WikiMedia Commons''']]

[[Image:microglia.jpg|thumb|right|150px|Microglia (immunohistochemical staining.) Grzegorz Wicher, '''WikiMedia Commons''']]

Microglia are the CNS version of a mononuclear phagocyte system as the normal phagocytic white blood cells are unable to cross the blood-brain barrier. Microglial cells are derived from [[Bone Marrow - Anatomy & Physiology|bone marrow]] and are first seen in the brain just prior to the vascularistion stage of brain development. There are two populations of microglial cells; extrinsic cells which are located perivascularly and in the meninges, and intrinsic cells which are located within the substance of the neural tissue.

 

* Microglia are the CNS representatives of mononuclear phagocyte system.

** As such, they are derived from [[Bone Marrow - Anatomy & Physiology|bone marrow]], and are first seen in brain just before vascularistion.

The microglia effectively act as macrophages where they rapidly respond to any type of injury. However, microglia differ from other representatives of mononuclear phagocyte system by their low expression of MHC-2. When undertaking a phagocytic response, MHC-2 can be easily up-regulated. Each type of microglia has a different turnover rate; perivascular and meningeal microglia turnover fairly rapidly whilst intrinsic microglia have a very slow turnover.

* There are two populations of microglial cells:

*# '''Extrinsic cells'''

*#* Located perivascularly and in the meninges.

*# '''Intrinsic cells'''

*#* Located within the substance of the neural tissue.

 

[[Image:microglia.jpg|thumb|right|150px|Microglia (immunohistochemical staining.) Grzegorz Wicher, '''WikiMedia Commons''']]

* Microglia act as macrophages.

** They rapidly respond to any type of injury.  

* However, microglia differ from other representatives of mononuclear phagocyte system by their low expression of MHC-2.

** MHC-2 is easily up-regulated though.

* The different types of microglia have different turnover rates.

** Perivascular and meningeal microglia turnover fairly rapidly.

** Intrinsic microglia have a very slow turnover.

==Ependymal Cells==

==Ependymal Cells==