If pressure from outside the lungs causes atelectasis, your doctor will treat the cause of the pressure. For example, if the cause is a tumor or fluid buildup, your doctor will remove the tumor or fluid. This will allow your lung to fully expand. Atelectasis Caused by a Blockage
Pilus. Definition. noun, plural: pili. (microbiology) Short, filamentous projection on a bacterial cell, used not for motility but for adhering to other bacterial cell (especially for mating) or to animal cells. Supplement. Bacterial pili are involved in cell adhesion.
Closely related to pili are structures called fimbriae (singular: fimbria). These are short, filamentous structures, present in large numbers that aid in cell adherence to surfaces. A bacterium that has fimbriae is usually covered with short hair-like fibers.