Final answer:
In exocytosis, vesicles typically come from the Golgi apparatus, where substances are packaged and then transported to the plasma membrane to be released outside the cell.
Step-by-step explanation:
In exocytosis, vesicles for export typically come from the Golgi apparatus. After substances are packaged into membrane-bound vesicles within the cell, these vesicles travel from the Golgi to the plasma membrane. Upon reaching the plasma membrane, the vesicle membrane fuses with the cell membrane and releases its contents into the extracellular space, which includes the interstitial fluid. This process is essential for cells that manufacture and secrete substances, such as digestive enzymes from the stomach and pancreas, hormones from endocrine cells, and histamine from immune cells.