structure of axon. in nervous system: Axon. The axon arises from the soma at a region called the axon hillock, or initial segment. This is the region where the plasma membrane generates nerve impulses; the axon conducts these impulses away from the soma or dendrites toward other neurons.
The type of land form that the Sierra Nevada and coastal ranges have is called a basin.
1 The higher area is sometimes called a horst and the lower a graben (see the picture below). 2  The Sierra Nevada Mountains in the western United States are fault-block mountains. 3  Volcanic mountains-Mountains that are caused by volcanic activity are called volcanic mountains.