HA20 is a low mag EM of a plasma cell (similar to the ones in HA18/19). The large Golgi Complex is indicated by the lines labeled G. Plasma cells synthesize and constitutively (constantly) secrete antibodies, so they have an abundant RER (ER). PM indicates the cell membrane, M a mitochondrion, NuE the nuclear envelope, P a nuclear pore, Ch the heterochromatin, and N the nucleus. To help you understand the boundary between this cell and its surrounding extracellular matrix, trace its cell membrane (HA20L).