Brain's Gray Matter: Why is it Gray?

[timejim]

I hope this question doesn't sound too stupid but is the brain really gray? That is, is the brain tissue itself gray in appearance? If it is, why is it?
If it is, is it the only human organ that is Gray?

 

[iansmith]

Yes, the grey matter is grey. Look at the pictures on this site.
http://www.gwc.maricopa.edu/class/bio201/brain/brnshp3.htm

The white matter is also present which is cause by cell responsible for the myelin sheath

 

[Moonbear]

The brain on the left in that link looks like one that's been soaked in or perfused with formalin or paraformaldehyde. Those fixatives give the brain a yellowish color. The image on the right looks like a lighting issue. A fresh brain looks only slightly grayish. White, myelinated fiber tracts are only slightly brighter white looking, but the color difference is visible. Gray matter is non-myelinated neurons and white matter is myelinated neurons. The spinal cord, in comparison, looks much whiter than the brain because it contains far more myelinated axons and they are on the outside. If you cut a cross section of a spinal cord, the center looks more gray, where there is less myelination.