Sialolithiasis (sigh a lo THIGH a sis) is a condition where tiny salivary stones form in the glands. The stones, called sialoliths, are made of calcium. Some stones do not cause any symptoms, but some stones block the ducts. The saliva flow is partially or completely stopped.he three major salivary glands are the parotid gland, submandibular gland (also called the submaxillary gland), and sublingual glands. Saliva drains into the mouth through small tubes called ducts.
NASA facilities. NASA facilities exist across the United States, but also across the world. NASA Headquarters in Washington, DC provides overall guidance and political leadership to the agency. There are 10 NASA field centers, which provide leadership for and execution of NASA's work.
Zoom out to find Houston George Bush Intercontinental Airport (IATA code: IAH) in north, distance from city center: 20 miles (32 km). Zoom out to find Lyndon B. Johnson Space Center (blue marker) located in the Bay Area of southeast Houston. Space Center Houston is the National Aeronautics and Space Administration's center for American human spaceflight activities. To find a location use the form below. To view just the map, click on the Map button. Space station flight control room in the Mission Control Center at NASA's Johnson Space Center-Photo: NASA Archive. Bookmark/share this page. To find a location type: street or place, city, optional: state, country.