Editing Olfactory system (section)

===Peripheral===
The peripheral olfactory system consists mainly of the [[nostril]]s, [[ethmoid bone]], [[nasal cavity]], and the [[olfactory epithelium]] (layers of thin tissue covered in [[mucus]] that line the nasal cavity). The primary components of the layers of [[epithelial tissue]] are the [[mucous membranes]], [[olfactory glands]], [[olfactory receptor neurons|olfactory neurons]], and [[afferent nerve fiber|nerve fibers]] of the [[olfactory nerves]].<ref>{{citation |title=Neuroscience |year=2001 |chapter=The Organization of the Olfactory System |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK10982/ |edition=2nd |location=Sunderland, MA |publisher=[[Sinauer Associates]] |access-date=7 August 2016 |veditors=Purves D, Augustine GJ, Fitzpatrick D, et al}}</ref>

Odor molecules can enter the peripheral pathway and reach the nasal cavity either through the nostrils when inhaling ([[olfaction]]) or through the throat when the tongue pushes air to the back of the nasal cavity while chewing or swallowing (retro-nasal olfaction).<ref name=Boroditsky/> Inside the nasal cavity, mucus lining the walls of the cavity dissolves odor molecules. Mucus also covers the olfactory epithelium, which contains mucous membranes that produce and store mucus, and olfactory glands that secrete [[metabolic pathway|metabolic enzymes]] found in the mucus.<ref name=Mori>{{citation|chapter=Odor and Pheromone Molecules, Receptors, and Behavioral Responses: Odorant Dynamics and Kinetics (Chapter 2.5.2)|title=The Olfactory System: From Odor Molecules to Motivational Behaviors|editor-first=Kensaku|editor-last=Mori|year=2014|location=Tokyo|publisher=Springer|page=32}}</ref>

==== Transduction ====
{{anchor|Transduction}}
[[File:Action potential propagation animation.gif|thumb|Action potential propagated by olfactory stimuli in an axon.]]

[[Olfactory receptor neurons|Olfactory sensory neurons]] in the epithelium detect odor molecules dissolved in the mucus and transmit information about the odor to the brain in a process called [[sensory transduction]].<ref name=Rodriguez>{{citation|last=Rodriguez-Gil|first=Gloria|title=The Sense of Smell: A Powerful Sense|date=Spring 2004|access-date=27 March 2016|url=http://www.tsbvi.edu/seehear/summer05/smell.htm}}</ref><ref name="Bushak">{{citation |last=Bushak |first=Lecia |title=How Does Your Nose Do What It Does? The Inner Workings Of Our Sense Of Smell |date=5 March 2015 |url=http://www.medicaldaily.com/how-does-nose-smell-inner-workings-our-sense-smell-324566 |website=[[Medical Daily]] |access-date=6 August 2016}}</ref> Olfactory neurons have [[cilia]] (tiny hairs) containing [[olfactory receptor]]s that bind to odor molecules, causing an electrical response that spreads through the [[sensory neuron]] to the [[Olfactory nerve|olfactory nerve fibers]] at the back of the [[nasal cavity]].<ref name=Boroditsky>{{citation|date=27 July 1999|first=Lera|last=Boroditsky|title=Taste, Smell, and Touch: Lecture Notes|website=Psych.Stanford.edu|url=http://www-psych.stanford.edu/~lera/psych115s/notes/lecture11/|access-date=6 August 2016|archive-url=https://web.archive.org/web/20161009020907/http://www-psych.stanford.edu/~lera/psych115s/notes/lecture11/|archive-date=9 October 2016|url-status=dead}}</ref>

Olfactory nerves and fibers transmit information about odors from the peripheral olfactory system to the central olfactory system of the brain, which is separated from the epithelium by the [[cribriform plate]] of the [[ethmoid bone]]. Olfactory nerve fibers, which originate in the epithelium, pass through the cribriform plate, connecting the epithelium to the brain's [[limbic system]] at the [[olfactory bulbs]].{{sfn|Mori|2014|page=182|ps=, "The Study of Humans Uncovers Novel Aspects in Brain Organization of Olfaction (Chapter 9.2)"}}