text: Guidepost cells direct and organize these structures. By binding to plexins, semaphorins direct the movement of these structures.
full_question: Guidepost cells direct and organize these structures. By binding to plexins, semaphorins direct the movement of these structures. In these structures, microtubules and F-actin at the "growth cone" move toward positive stimuli. The Hodgkin-Huxley model was formulated from data taken from the "giant" structure of this kind in squid. The last site of summation prior to this structure occurs at its namesake (*) "hillock." Saltatory conduction takes place at naked sites along this structure known as Nodes of Ranvier. Either oligodendrocytes or Schwann cells supply a substance that insulates these structures. They terminate at synapses. For 10 points, name these often-myelinated long parts of neurons, contrasted with dendrites.
first_sentence: Guidepost cells direct and organize these structures. By binding to plexins, semaphorins direct the movement of these structures.
raw_answer: axons [prompt on neurons before mentioned; prompt on nerve cells before "neurons" is mentioned]