Astrocytes are the star shaped cells that are present in the brain and spinal cord. The exact constitution of astrocytes in the brain is not known and almost 20% to 40% astrocytes are present in brain.
The astrocytes acts as the blood brain barrier and involved in the process of brain scarring. Astrocytes also regulate ions concentration by propagating the calcium ion channels in response to the stimulus. Astrocytes also generate a response by the calcium dependent release of glutamate.
Loess is a sediment that is formed from silt deposits due to wind. The composition of the silt is clay and sand. The components are cemented together by calcium carbonate. The silts are blown by wind and accumulate in a singular location.