Figure 13: Diagram depicting Exocytosis process

Types of exocytosis: Exocytosis are of two types.  Constitutive exocytosis and Regulated exocytosis

1. Constitutive exocytosis: Secretory materials are continuously released without requirement of any specific kind of signal.
2. Regulated exocytosis: Regulated exocytosis requires an external signal, a specific sorting signal on the vesicles for release of components. It contains a class of secretory vesicles that fuse with plasma membrane following cell activation in presence of signal. Examples of regulated exocytosis are secretion of neurotransmitter, hormones and many other molecules

Figure 14: Types of exocytosis. (a) Constitutive secretion and (b) Regulated secretion