Final answer:
Secretory vesicles remain inactive in the cytosol until a signal prompts them to release their contents through exocytosis, a process important for cellular communication and waste removal.
Step-by-step explanation:
Secreted products are sorted into larger secretory vesicles that remain inactive in the cytosol until a signal is received. These vesicles are involved in the process of exocytosis, a crucial mechanism for cellular communication and waste removal.
Vesicles formed from the Golgi apparatus' trans face can either become transport vesicles, depositing their contents within the cell, or secretory vesicles, fusing with the plasma membrane to release content outside the cell. Whether the release of these vesicles' contents is immediate or delayed depends on the cell's regulatory mechanisms. Regulated secretion means that the vesicles are stored and only release their contents upon receiving a specific signal, which is characteristic of specialized cells such as mast cells that secrete histamine in response to pathogens.