Fig. 6. Internalization of the apical membrane in mitochondria-rich cells (MRCs). Yolk-sac MRCs were double-labeled by Na⁺/K⁺-ATPase antiserum (second antibody conjugated with FITC; green) and Con-A–Texas-Red (red), which was internalized into the cytoplasm of MRCs (A). (B,C) Optical sections 3 µm and 6 µm beneath the apical surface. Magnification: 2000x. Scale bars: 15 µm.