Fig. 5.

Polyribosomes in a dendrite (a) and in a myelinated axon (b). Polyribosomes are localized near the axolemma both in the dendrite and in the myelinated axon. No rough ER is found in the axon, however, thin membrane-bounded vesicular structures are observed among axoplasmic polyribosomes. The electron density of their membrane is similar to that of myelin sheath (arrowheads). A homogeneous electron-dense structure (*) is present. Bar, 0.25 µm.