GM2 is found mainly in neurons, so without HEX-A, it accumulates inside lysosomes.

GM2通常分布在神经元中，因此如果HEX-A缺失，GM2就会在溶酶体中积蓄。

Also, between the circular and the longitudinal muscle layer, there's a plexus, or networks of nerves, which help coordinate muscle contraction and relaxation.

另外，在内外纵之间，还有神经丛（神经络）的分布；神经丛可以协调肠的收缩与舒张。

In the thoracic region of the spine, neural crest cells differentiate into the neurons of the sympathetic chain, lying on either side of the entire spinal cord.

在脊柱的胸椎节段，神经嵴细胞分化成交感神经链的神经元，分布在整条脊髓的两侧。

That's the stage when individuals usually experience pain, although pain can also occur when the caries lesion involves the dentin layer since sensory nerve fibers travel through tubules in the dentin.

在这个阶段，患者常会感到疼痛，但牙本质层受累产生龋坏时也可能有疼痛产生，因为感觉神经也分布在牙本质的管中。