Electron micrographs of reticulocytes cultured for 40 hours. Images of reticulocytes demonstrating mitochondria (m) in various states of degradation: in close association with a vacuole (white arrowheads in left panel), with ballooning of the outer membrane (black arrowheads in center panel), and intact (right panel). Intracellular vacuoles (v) contain cellular debris, and the reticulocytes demonstrate exocytic activity (asterisks). Magnification: left, × 20 000; center, × 24 000; right, × 35 000.