Search results
Results from the WOW.Com Content Network
White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation.
There is a difference between the cerebral blood volume of gray and white matter. The cerebral blood volume value of gray matter is about 3.5 +/- 0.4 ml/100g, and the white matter is about 1.7 +/- 0.4 ml/100g. The gray matter is nearly twice that of white matter. [3]
Grey matter, or gray matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil (dendrites and unmyelinated axons), glial cells (astrocytes and oligodendrocytes), synapses, and capillaries.
The gray matter changes can be observed via both gray matter density and gyrification. That the white matter loss is not nearly as clear as that for gray matter indicates that changes also occur in non-neural tissue, e.g. the vasculature or microglia.
It is the largest white matter structure in the human brain, about 10 cm (3.9 in) in length and consisting of 200–300 million axonal projections. [ 2 ] [ 3 ] A number of separate nerve tracts, classed as subregions of the corpus callosum, connect different parts of the hemispheres.
They are the most widespread cell lineage, including oligodendrocyte progenitor cells, pre-myelinating cells, and mature myelinating oligodendrocytes in the CNS white matter. [3] Non-myelinating oligodendrocytes are found in the grey matter surrounding and lying next to neuronal cell bodies. They are known as neuronal satellite cells, and their ...
The anterior and posterior grey columns present as projections of grey matter and are also known as the horns of the spinal cord. The white matter is located outside of the grey matter and consists almost totally of myelinated motor and sensory axons. Columns of white matter known as funiculi carry information either up or down the spinal cord.
Age-related decrease in gray matter volume was the largest contribution to changes in brain volume. Moreover, neuronal density appears to decrease, white matter microstructure gets altered and energy metabolism in the cerebellum gets altered. [16] General cortical atrophy occurs in aging and e.g. the caudate nucleus volume appears to decrease.