Most small-molecule neurotransmitters are stored in small vesicles that range from 40 to 60 nm in diameter and, in electron micrographs, appear to have clear centers. The vesicles that store neuropeptides are larger, ranging from 90 to 250 nm in diameter.
The world's largest concentration of natural sandstone arches. 1  Hike the 1.5 mile trail leading to the base of Delicate Arch to experience one of the most breathtaking vistas in the world. 2  Your family will love the short trails in the Windows Section that lead right up to several massive arches.
âDeath Trapâ. Review of Gateway Arch. Owner description: The Museum of Westward Expansion closed, pending installation of all new museum exhibits. As of March 2, 2015, entry-only ticket or tram ticket required to enter Arch. The nation's tallest monument at 630 feet, the Gateway Arch has beckoned visitors since June 1967. The Gateway Arch commemorates Thomas Jefferson and the role St. Louis played in the westward expansion of the United States.