The fine structural organization of axons has been extensively investigated since the mid-1950s using various forms of electron microscopy (EM), such as standard transmission, high voltage, and EM combined with freeze etching. From such studies, we know that the axon cytoplasm contains many of the same components as the neuronal soma and dendrites; that is, mitochondria, multivescicular bodies, agranular endoplasmic reticulum (ER), neurofilaments, and microtubules. Axons, however, do not have free ribosomes or granular ER and therefore do not engage in protein synthesis (Fig. 3; Table I).
Was this article helpful?