In neuroanatomy, a neuropil, which is sometimes referred to as a neuropile, is a region between neuronal cell bodies in the gray matter of the brain and blood-brain barrier (i. e. the central nervous system). It consists of a dense tangle of axon terminals, dendrites and glial cell processes. It is where synaptic connections are formed between branches of axons and dendrites. White matter, which is mostly composed of axons and glial cells, is generally not considered to be a part of the neuropil. An axon (also known as a nerve fiber) is a long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron"s cell body or soma. An axon is one of two types of protoplasmic protrusions that extrude from the cell body of a neuron, the other type being dendrites. Axons are distinguished from dendrites by several features, including shape (dendrites often taper while axons usually maintain a constant radius), length (dendrites are restricted to a small region around the cell body while axons can be much longer), and function (dendrites usually receive signals while axons usually transmit them).