Human brain the largest cells (by size of cell body) in the nervous system. The adult human brain is estimated to contain 86±8 billion neurons, with a roughly equal number (85±10 billion) of non-neuronal cells. Out of these neurons, 16 billion (19%) are located in the cerebral cortex, and 69 billion (80%) are in the cerebellum. Types of glial cell are astrocytes (including Bergmann glia), oligodendrocytes, ependymal cells (including tanycytes), radial glial cells and microglia. Astrocytes are the largest of the glial cells. They are stellate cells with many processes radiating from their cell bodies. Some of these processes end as perivascular
Human Endogenous Retrovirus-W influence the expression of HERV-W. Through qPCR methods and infection of cells with influenza and human herpes simplex 1 it was found that HERV-W has a heighted expression in a cell-specific manner when infected but no mechanism was revealed. Also, when these cells are placed in stressful environments such as serum deprivation similar and increased expression of HERV-W is also recorded. This suggests that HERV-W is modulated by environmental effects. Another study also infected cells with influenza to show that this virus can transactivate HERV-W elements. Influenza produces Glial Cells missing 1 (GCM1) that can act as an enhancer to