Editing Chemoreceptor (section)

===Control of breathing===
Particular chemoreceptors, called [[acid-sensing ion channel|ASICs]], detect the levels of [[carbon dioxide]] in the blood. To do this, they monitor the concentration of [[hydrogen ion]]s in the blood, which decrease the [[pH]] of the blood. This can be a direct consequence of an increase in carbon dioxide concentration, because aqueous carbon dioxide in the presence of [[carbonic anhydrase]] reacts to form a [[proton]] and a [[bicarbonate]] ion.{{citation needed|date=May 2015}}

The response is that the respiratory centre (in the medulla), sends [[nerve impulse|nervous impulses]] to the external [[intercostal muscles]] and the [[diaphragm (anatomy)|diaphragm]], via the [[intercostal nerve]] and the [[phrenic nerve]], respectively, to increase breathing rate and the volume of the lungs during inhalation.

Chemoreceptors that regulate the depth and rhythm of breathing are broken down into two categories.{{Citation needed|date=July 2010}}

* [[central chemoreceptors]] are located on the ventrolateral surface of [[medulla oblongata]] and detect changes in pH of cerebrospinal fluid. They have also been shown experimentally to respond to hypercapnic hypoxia (elevated {{CO2}}, decreased O2), and eventually desensitize, partly due to redistribution of bicarbonate out of the cerebrospinal fluid (CSF) and increased renal excretion of bicarbonate.<ref>{{cite book |doi=10.1016/B978-1-4377-1679-5.00025-9 |chapter=Pulmonary Physiology |title=Pharmacology and Physiology for Anesthesia |year=2013 |last1=Lumb |first1=Andrew B. |last2=Horner |first2=Deborah |pages=445–457 |isbn=9781437716795 }}</ref> These are sensitive to pH and {{CO2}}.<ref>{{Cite web|title=Central Chemoreceptors|url=http://pathwaymedicine.org/central-chemoreceptors|access-date=2021-03-16|website=pathwaymedicine.org|language=en|archive-date=2021-04-13|archive-url=https://web.archive.org/web/20210413171352/http://pathwaymedicine.org/Central-Chemoreceptors|url-status=dead}}</ref>
* [[peripheral chemoreceptors]]: consists of aortic and carotid bodies. [[Aortic body]] detects changes in blood oxygen and carbon dioxide, but not pH, while [[carotid body]] detects all three. They do not desensitize. Their effect on breathing rate is less than that of the central chemoreceptors.{{citation needed|date=May 2015}}