Secretion is the movement of material from one point to another chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, is the removal of certain substances or waste products. The classical mechanism of cell secretion is via secretory portals at the cell plasma membrane called porosomes. Porosomes are permanent cup-shaped lipoprotein structure at the cell plasma membrane, where secretory vesicles transiently dock and fuse to release intra-vesicular contents from the cell.