Transmission electron micrograph showing pinocytosis in monkey placenta. Note the desmosomes. Magnification 61,000x Pinocytosis, the transport of fluid into a cell by means of local infoldings by the cell membrane so that a tiny vesicle or sac forms around each droplet, which is then taken into the interior of the cytoplasm. Desmosome, a structure that forms the site of adhesion between two cells, consisting of a dense plate in each adjacent cell separated by a thin layer of extracellular material.