Human Lungs ‘Brush’ Themselves Clean of ContaminantsSpace Friday, September 7th, 2012
(NaturalNews) Human lungs contain a tiny network of constantly moving “brushes” that flush contaminants out of the respiratory system, according to research conducted by scientists from the University of North Carolina and published in the journal Science.
Scientists have known for a long time that the respiratory system protects itself by means of a coating of mucus, which is sticky enough to trap pollutants and keep them from reaching the body’s cells. When needed, the body can expel this mucus through a runny nose or a cough.
“The air we breathe isn’t exactly clean, and we take in many dangerous elements with every breath,” said lead researcher Michael Rubinstein.
“We need a mechanism to remove all the junk we breathe in, and the way it’s done is with a very sticky gel, called mucus, that catches these particles and removes them with the help of tiny cilia. The cilia are constantly beating, even while we sleep.
“In a coordinated fashion, they push mucus, containing foreign objects, out of the lungs, and we either swallow it or spit it out. These cilia even beat for a few hours after we die. If they stopped, we’d be flooded with mucus that provides a fertile breeding ground for bacteria.”
But until now, researchers have never understood why the mucus does not stick to or even infiltrate the respiratory cells themselves. The foremost theory, known as the “gel-on-liquid model,” posited that an as-yet-undiscovered watery “periciliary” layer kept mucus and cilia separate. The problem with this theory was always that to the best of scientific knowledge, mucus should eventually dissolve into such a watery layer, not remain separate.
“We can’t have a watery layer separating sticky mucus from our cells because there is an osmotic pressure in the mucus that causes it to expand in water,” Rubinstein says. “So what is really keeping the mucus from sticking to our cells?”