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.
ALERT: The Tram Ride to the Top of the Arch is TEMPORARILY CLOSED for system improvements until late-April 2017. During the closure, no ticket is required for entry into the Arch facility which includes The Arch Store and the award-winning documentary, Monument to the Dream. (free showings throughout the day). Please Note: The Museum of Westward Expansion, located under the Gateway Arch is closed for significant renovations.