In this Article. In this Article. A solitary pulmonary nodule (SPN) is a single abnormality in the lung that is smaller than 3 cm in diameter. Generally, a pulmonary nodule must grow to at least 1 cm in diameter before it can be seen on a chest X-ray.
Osmosis is the scientific process of transferring fluid between molecules. When molecules move in and out of a cell to achieve the same concentration of something, like salt, on both sides, then osmosis is happening.
Osmosis is the movement of water molecules through a selectively permeable membrane from higher water concentration to a lower water concentration - or - down a concentration gradient. Animal cells are surrounded only by the membrane and may swell up and burst if too much water enters by osmosis. Plant cells have a strong cell wall outside the membrane and this wall prevents them from swelling up too much. They become stiff and hard like a well inflated football. The cell is turgid.