Table 1.
Number of single microtubules and microtubular fascicles at five different levels from the distal part of the initial segment to the first paranode
| Level | Distance (µm) | Diameter (µm) | f1 | f2 | f3 | f4 | f5 | f6 | f7 | f8 | f9 | f10 | f11 | f12 | Total | Percentage number |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IS | 1.32 | 2.30 | 24 | 25 | 18 | 8 | 6 | 1 | 1 | 1 | 1 | 220 | 89 | |||
| ISend | 0.00 | 2.30 | 28 | 22 | 16 | 9 | 2 | 4 | 2 | 1 | 213 | 87 | ||||
| Para1 | 0.30 | 2.47 | 18 | 23 | 15 | 7 | 6 | 2 | 1 | 1 | 1 | 1 | 216 | 92 | ||
| Para2 | 1.32 | 3.28 | 26 | 13 | 10 | 6 | 2 | 2 | 128 | 80 | ||||||
| Para3 | 1.40 | 3.32 | 26 | 9 | 6 | 5 | 1 | 1 | 93 | 72 |
f1, number of single microtubules; f2–f12, number of microtubular fascicles containing 2–12 microtubules. ‘Total number’, the total number of microtubules in a cross cut axon profile; ‘percentage’, the proportion of fasciculated microtubules in the total microtubules. The five levels are described in Fig. 2(a).