Neurons transfer information across the body in the form of electrical signals (long-distance communication) and chemical signals (short-distance communication). Each part of the neuron is specially designed to receive and send information in an efficient manner.

Dendrites: These extensions from the cell body are highly branched and receive incoming information from other neurons.

Cell Body: The cell body contains most of the organelles of the neuron, including the mitochondria, golgi apparatus, smooth endoplasmic reticulum, lysosomes, and (importantly) the nucleus. 

Axon Hillock: This cone-shaped base of the neuron. It connects the cell body to the axon.

Axon: Though the length of the axon differs depending on the type of neuronal cell, it is often a very long extension that carries the signal from the dendrites, all the way to the end of the neuron.

Schwann Cell: This is a type of glial cell that wraps around the nerve fibers of the neuron

Nodes of Ranvier: These are small regions of breakage of myelin sheath along myelinated axons. These breaks are crucial for the continuance of the electrical signal across the axon. They allow for the exchange of ions, mainly potassium and sodium. 

Myelin Sheath: The myelin sheath insulates the electrical impulses that travel down the axon of the neuron, increasing their speed.

Axon Terminal: At the axon terminal, neurotransmitters are released.

Synapse: This junction between the axon terminal and dendrites of two neurons is where signals are exchanged and pass between neurons. Neurotransmitters are released across the synapse and begin a signal in the next neuron. 

*Note: Much of the following information on the CNS and PNS of reptiles is based off general anatomical research on reptiles, and iguana species that are closely related to the marine iguana, such as the green iguana (Iguana iguana). Due to the marine iguana being endemic to the Galápagos Islands, there is little research that exists beyond very specific studies. What information exists has been used.