A mixed tideâtwo uneven tides a day, or one high and one lowâis also possible. Tides vary on timescales ranging from hours to years due to a number of factors. To make accurate records, tide gauges at fixed stations measure water level over time.
Top 10 facts about the world. Oligodendrocytes, also known as oligodendroglia, are a type of brain cell in the central nervous system that belongs to the glial cell family. The main purpose of glial cells is maintenance and support of nervous system cells.
*astrocytes= form the blood brain barrier. *ependymal= produce CSF (cerebral spinal fluid) *oligodendrocytes= form the myelin sheath that wraps around the axon. The four types in the CNS are microglia, astrocytes, ependymal, and oligodendrocytes. *microglia= phagocytes *astrocytes= form the blood brain barrier *ependymal= produce CSF (cerebral spinal fluid) *oligodendrocytes= form the myelin sheath that wraps around the axon.