The illustration shows an axon. Nerve cells generally consist of dendrite, perikaryon, and axon. Dendrites (gr. dendros = tree) receive signals by a preceding nerve cell and are shown in the upper third of the image. The perikaryon (cell body) is the contact point for dendrites and origin of the axon. It contains organelles and the nucleus. The lower half of the picture shows the axon with its ramifications. It forwards the signal to the next nerve cell. The myelin sheath (Schwann cells) surrounds the axon in ordert to isolate it, which increases the nerve conduction velocity. The Ranvier`s nodes are between the myelinated parts of the axon.