The axon is the long, thin sending part of the neuron (see Figure 1, below).
It is between 1 and 20 microns (1 and 20 1/25,000 inch) thick, depending on its type, but it can be
as long as 1.5 meters (5 ft.)long in an adult human. It starts where the dendrites come together to
form the neuron's single axon, which. Axons usually branch to connect to several locations. It connects
to (on the average) 1,000s of other neurons.
Axon terminals (terminal buttons or boutons) are the endings of the axon branches. They form the sending part of synapses, where the axon of one neuron can affect the dendrite of another neuron. See Exercise E09_29h
The axon's long, thin shape and branching send information efficiently over long distance and to different locations, reflecting its specialization for communication. Axons carry information from the senses to the brain, distribute it to different parts of the brain, or send signals out to muscles and glands which generate the behaviors you do.