The walls of arteries and veins are composed of endothelial cells, smooth muscle cells and extracellular matrix (including collagen and elastin). These are arranged into three concentric layers: intima, media and adventitia. The intima is the inner layer abutting the vessel lumen.he walls of arteries and veins are composed of endothelial cells, smooth muscle cells and extracellular matrix (including collagen and elastin). These are arranged into three concentric layers: intima, media and adventitia. The intima is the inner layer abutting the vessel lumen.
The correct phrase is It's not over until the fat lady sinks and has its origins in the game of billiards. The black eight ball was commonly referred to as the fat lady so no matter how bad the game was for a competitor it wasn't over until the fat lady sank.!! Debbie Pollard, Yorkshire uk.
It's originally from the opera, where many of the lead singers were largeâ¦ women, but now is used to remind people that it ain't over til it's over. The opera ain't over till the fat lady sings, was coined by Dan Cook, a sports broadcaster in April, 1978. See link below for history and trivia That is something that was observed at an opera and jokingly applied to other events.