|P.T3 right column bottom paragraph: "Besides the chromosomes, many other large objects within the cell must be moved quickly to particular locations
by directed intracellular transport. The need for directed transport rather than reliance on simple diffusion and trapping to localize cellular components is best imagined in large
cells, such as neurons. The longest neuron in the human body has a single threadlike projection (the axon), a few
micrometers in diameter, that reaches from the base of the spine to the foot, a distance of up to one meter." For axon length of over a meter see Cavanagh (1984, PMID 6144984 p.1284 right column bottom paragraph:) "Adequate processing and maintenance of axons stretching perhaps more than a metre for three score years or longer demands a well-balanced metabolic economy..."