The authors suggest their model explains the genesis of the complicated helicoidal texture, and that the model indicates the cell has intrinsic, versatile tools for creating a variety of textures. At the cell surface, the vacuole fuses with the plasma membrane, and the contents of the vacuole are deposited outside the cell. Various aspects of the process are visible with both light and electron microscopy in a variety of cell systems, and this is the process primarily responsible for excretion and secretion by individual cells. Composed of the protein tubulin, microtubules are part of the cytoskeleton of biological cells, the quasi-rigid matrix that among other things determines cell shape. The microtubules are 25 nanometers in diameter and occur in regular arrays.
Cortical microtubules are microtubules structuring the surfaces of cells.