part_of part of part of extracellular space extracellular exosome extracellular vesicular exosome cellular_component GO:0070062 A vesicle that is released into the extracellular region by fusion of the limiting endosomal membrane of a multivesicular body with the plasma membrane. Extracellular exosomes, also simply called exosomes, have a diameter of about 40-100 nm. exosome extracellular vesicle