Final answer:
Exocytosis is the process where secretory vesicles fuse with the plasma membrane to release their contents outside the cell.
Step-by-step explanation:
The fusion of a secretory vesicle with the plasma membrane to discharge the contents of the vesicle is called exocytosis. This process is crucial for cells to release substances, such as proteins, neurotransmitters, and waste products.
During exocytosis, the secretory vesicles, which are spherical membranous sacs, move toward and merge with the plasma membrane. The contents are then released to the exterior of the cell. This can occur in a constitutive manner, where secretion is continuous, or in a regulated form, which occurs in response to specific cellular signals.