Anatomy
The directed growth of axons depends on structure at the end of the tip of a growing axon referred to as a growth cone. Growth cones, in brief, are motile structures that explore the environment and ultimately guide the extension of the axon. The response of growth cones to various signaling molecules dictates the correct pathway and direction of growth of the axon. Growth cones possess a sheetlike expansion at the tip called the lamellipodium, from which extend fine processes called filopodia. The growth cone is necessary for the construction of neural pathways.
Although pioneer axons and follower axons both possess growth cones, there are several morphological differences related to the function of pioneer axons. The structure of the growth cone changes whenever an axon reaches a territory not previously innervated, or if a choice in direction is required. Mainly, the lamellipodium increase in size and extend numerous filopodia in order to collect as much sensory information as possible.
Read more about this topic: Pioneer Axon
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