The CV<sub>II</sub> neurites are divided into five developmental phases.

2014-08-28T03:07:02Z (GMT) by Guangming Gan Huihui Lv Wei Xie
<p>In P phase (<b>A</b>), there are not synapses, microtubules, or synaptic vesicles in the neurite. In S phase (<b>B</b>), there are some microtubules, mitochondria, or different sizes of synaptic vesicles, but no synapses. In T phase (<b>C</b>–<b>D</b>), there are residual microtubules and a greater variety in the size of synaptic vesicles in the neurite; the synapse is immature, and there is no T-bar structure formation. In B phase (<b>B</b>, <b>E</b>–<b>L</b>), the neurites look bifurcated or dendritic, and the two different diameters of synaptic vesicles remain present. In M phase, there are dark cytoplasm, typical T-bar structures and a lot of commensurate synaptic vesicles cluster around it, but the appearance of the neurite remain bifurcated or dendritic, and have several branches around it (<b>M</b>–<b>N</b>). In embryo stage, the synapses have not T-bar structures (<b>F</b>), but have the immature T-bar structures and dark cytoplasm throughout the larval stage (<b>G</b>–<b>L</b>) in B phase. In the same diagram, the large black box is enlarged from the small white box, and <b>H</b> is the magnification of the <b>G</b> diagram box. Triangle indicates synapse, thick arrow indicates the big dark synaptic vesicles, thin arrow indicates microtubules, asterisk indicates the axon and black long triangle indicates the nascent branch of neurite in B phase (<b>B</b>). <b><i>P</i></b> indicates P phase, <b><i>S</i></b> indicates S phase, <b><i>T</i></b> indicates T phase, <b><i>B</i></b> indicates B phase, <b><i>M</i></b> indicates M phase and Mi indicates mitochondria. Scale Bar A: 100 nm; B–H, K–M: 200 nm; I: 500 nm.</p>