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.
Meaning, history and more. Millions of Americans will be celebrating Labor Day on Sept. 5, a day that marks the unofficial end of summer. It's celebrated with parades, parties and - of course - barbecues. But why do we celebrate Labor Day and what is its history? Here's some information from the U.S. Department of Labor.