In exocytosis, the membrane package, known as a vesicle, fuses with the cell membrane. This process allows the release of the contents of the vesicle into the extracellular environment. The vesicle membrane and the cell membrane merge together, creating a continuous membrane structure. This fusion event is facilitated by proteins called SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) and other regulatory factors present on both membranes.