Mena. Mena was founded in 1896 as a railroad town at the eastern foot of Arkansas's second highest peak, Rich Mountain (elev. 2,681).It is the eastern terminus of the Talimena Scenic Drive, a 54-mile byway that travels the crests of Rich and Winding Stair mountains between Mena and Talihina, Oklahoma.he byway and park provide impressive vistas of the Ouachita Mountains. The Mena Depot Center, located in a restored 1920 railroad depot, greets the town's visitors with tourism information, art and local history exhibits and railroad memorabilia. In Janssen Park, stands an 1851 log cabin still on its original site.
Structure [edit]. Schwann cells are a variety of glial cell that keep peripheral nerve fibres (both myelinated and unmyelinated) alive. In myelinated axons, Schwann cells form the myelin sheath (see above). The sheath is not continuous.Individual myelinating Schwann cells cover about 100 micrometres of an axonâequating to approximately 10,000 Schwann cells along a 1 metre length of the axon.n this sense, Schwann cells are the peripheral nervous system's analogues of the central nervous system 's oligodendrocytes. However, unlike oligodendrocytes, each myelinating Schwann cell provides insulation to only one axon (see image).
The major function of oligodendrocytes and Schwann cells is the formation of myelin. Myelin acts as an insulator of axonal segments and is a prerequisite for the high velocity of nerve conduction, of up to 200 m/second.The association of glial cells with axons is also found in invertebrates.chwann cells are the cellular counterparts to oligodendrocytes in the peripheral nervous system. Similarly to oligodendrocytes they form the myelin sheath. In contrast to the oligodendrocyte each Schwann cell is associated with only one axonal segment.