Fimbria (bacteriology)

In bacteriology, fimbria is a proteinaceous appendage in many gram-negative bacteria that is thinner and shorter than a flagellum. This appendage ranges from 3-10 nanometers in diameter and can be up to several micrometers long. Fimbriae are used by bacteria to adhere to one another and to adhere to animal cells. A bacterium can have as many as 1,000 fimbriae. Fimbriae are only visible with the use of an electron microscope.