exocytosis constitutive secretory pathway biological_process A process of exocytosis found in all eukaryotic cells, in which transport vesicles destined for the plasma membrane leave the trans-Golgi network in a steady stream. Upon exocytosis, the membrane proteins and lipids in these vesicles provide new components for the plasma membrane, and the soluble proteins inside the vesicles are released into the extracellular space. constitutive exocytosis GO:0045054