Surfactant: A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue, preventing the alveoli from collapsing.urfactant: A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue, preventing the alveoli from collapsing.
Guy Fawkes' Day is not a public holiday. Businesses, organizations and schools are open as usual. Public transport services run to their normal timetables. Some organizations, communities and municipalities may organize public bonfires or displays of fireworks on or around November 5.
Labor Day in the United States. Labor Day is on the first Monday of September every year. It was originally organized to celebrate various labor unions' strengths of and contributions to the United States' economy. Labor Day is a day off in the US.Labor Day is a day of rest for many Americans.Â©iStockphoto.com/Martin Novak.