Editing Neuron (section)

===Membrane===
Like all animal cells, the cell body of every neuron is enclosed by a [[plasma membrane]], a bilayer of [[lipid]] molecules with many types of protein structures embedded in it.<ref>{{Cite journal |last=Giménez |first=C. |date=February 1998 |title=[Composition and structure of the neuronal membrane: molecular basis of its physiology and pathology] |url=https://pubmed.ncbi.nlm.nih.gov/9563093/ |journal=Revista de Neurologia |volume=26 |issue=150 |pages=232–239 |issn=0210-0010 |pmid=9563093}}</ref> A lipid bilayer is a powerful electrical [[Insulator (electricity)|insulator]], but in neurons, many of the protein structures embedded in the membrane are electrically active. These include ion channels that permit electrically charged ions to flow across the membrane and ion pumps that chemically transport ions from one side of the membrane to the other. Most ion channels are permeable only to specific types of ions. Some ion channels are [[voltage-gated ion channel|voltage gated]], meaning that they can be switched between open and closed states by altering the voltage difference across the membrane. Others are chemically gated, meaning that they can be switched between open and closed states by interactions with chemicals that diffuse through the extracellular fluid. The [[ion]] materials include [[sodium]], [[potassium]], [[chloride]], and [[calcium]]. The interactions between ion channels and ion pumps produce a voltage difference across the membrane, typically a bit less than 1/10 of a volt at baseline. This voltage has two functions: first, it provides a power source for an assortment of voltage-dependent protein machinery that is embedded in the membrane; second, it provides a basis for electrical signal transmission between different parts of the membrane.