View source for Chyme

{{Short description|Semi-fluid mass of partially digested food}}
{{distinguish|Chyle|Chymex|Chime (disambiguation){{!}}Chime}}
{{more citations needed|date=January 2009}}
{{Infobox anatomy
|Name = Chyme
}}

'''Chyme''' or '''chymus''' ({{IPAc-en|ˈ|k|aɪ|m|ə|s}}; {{etymology|grc|''{{wikt-lang|grc|χυμός}}'' ({{grc-transl|χυμός}})|juice}})<ref>{{OEtymD|chyme}}</ref><ref>{{LSJ|xumo/s|χυμός|ref}}</ref> is the semi-fluid mass of partly digested food and digestive secretions that is formed in and expelled by the [[stomach]], through the [[pyloric valve]], into the [[duodenum]]<ref>{{cite Merriam-Webster|chyme}}</ref> (the beginning of the [[small intestine]]), where it is further transformed.<ref>{{cite encyclopedia |title=Chyme |url=https://britannica.com/science/chyme |encyclopedia=[[Encyclopædia Britannica]] |language=en |access-date=2025-01-25}}</ref> Chyme also contains cells from the mouth and esophagus that slough off from the mechanical action of chewing and swallowing.

Chyme results from the mechanical and chemical breakdown of a [[bolus (digestion)|bolus]] and consists of partially digested food, water, [[hydrochloric acid]], and various [[digestive enzyme]]s. Chyme slowly passes through the pyloric [[sphincter]] and into the duodenum, where the extraction of [[nutrient]]s begins. Depending on the quantity and contents of the meal, the stomach will digest the food into chyme in some time from 40 minutes to 3 hours.<ref>{{cite book |last= A. Potter|first= Patrica|date= 2013|title=Fundamentals of Nursing, 8th edition |publisher= Elsevier, Inc.|page= 1000|isbn=978-0-323-07933-4}}</ref> 
With a [[pH]] of approximately 2, chyme emerging from the stomach is very acidic.<ref>{{Cite book |last1=Hemmings |first1=Hugh C. |url=https://books.google.com/books?id=am_DS7rgypAC&q=chyme+is+highly+acidic |title=Pharmacology and Physiology for Anesthesia E-Book: Foundations and Clinical Application |last2=Egan |first2=Talmage D. |date=2012-12-06 |publisher=Elsevier Health Sciences |isbn=978-1-4557-3793-2 |pages=480 |language=en |quote=Chyme is a semifluid mixture consisting of a mixture of food and stomach secretions. In the stomach and when initially expelled from the stomach, chyme is highly acidic with  a pH of around 2. In the duodenum, pancreatic secretions of bicarbonate help to raise its pH}}</ref> The duodenum, a short section of the small intestine located between the stomach and the rest of the small intestine, secretes a [[hormone]], [[cholecystokinin]] (CCK), which causes the [[gallbladder]] to contract, releasing alkaline [[bile]] into the duodenum and reducing the chyme's low pH. CCK also causes the release of digestive enzymes from the [[pancreas]]. The duodenum also produces the hormone [[secretin]] to stimulate the pancreatic secretion of large amounts of [[sodium bicarbonate]], which then raises pH of the chyme to 7. Other secretions from the [[liver]] and from [[glands]] in the intestinal wall help in digestion, as these secretions contain a variety of digestive enzymes and chemicals that assist in the breakdown of complex compounds into those that can be absorbed and used by the body.

The linings of the stomach<ref>{{cite web |last=Forssell |first=H |year=1988 |title=Gastric mucosal defence mechanisms: a brief review |url=https://pubmed.ncbi.nlm.nih.gov/3072665/#:~:text=Substances%20*%20Antacids.%20*%20Bicarbonates.%20Prostaglandins. |website=PubMed |publisher=National Library of Medicine |access-date=25 October 2025}}</ref> and duodenum are protected by a thick layer of [[mucus]] and, in the duodenum, the neutralizing actions of the sodium bicarbonate and bile. Afterward, at a pH of 7, the enzymes that were present from the stomach are no longer active. The chyme moves through the [[jejunum]] and the [[ileum]], where digestion progresses, and the indigestible portion continues onward into the [[large intestine]], where [[anaerobic bacteria]] break down any proteins and starches in chyme that were not digested fully in the small intestine and at the same time help to package the remains. These bacteria also help synthesize [[vitamin B]] and [[vitamin K]], which will be absorbed along with other nutrients. When all of the nutrients have been absorbed from chyme, the remaining waste material changes into semisolid [[feces]]. The feces pass to the [[rectum]], to be stored until ready to be discharged from the body during [[defecation]].

==Uses==

The chyme of an [[weaning|unweaned]] calf is the defining ingredient of [[Rigatoni con la Pajata|pajata]], a traditional [[Roman cuisine|Roman recipe]]. Chyme is also sometimes used in [[Pinapaitan]], a bitter [[Ilocano people|Ilocano]] stew.

== See also ==
* [[Bolus (digestion)|Bolus]]
* [[Vomiting]]

== References ==
===Citations===
{{reflist}}
===Bibliography===
* {{cite book |last1=Hemmings |first1=Hugh C., Jr. |last2=Egan |first2=Talmage D. |title=Pharmacology and Physiology for Anesthesia |url= https://books.google.com/books?id=am_DS7rgypAC|year=2012 |publisher=Elsevier Health Sciences |location=Philadelphia |isbn=978-1-4377-1679-5}}
==Further reading==
* {{cite journal |author=Moxon, T. E., Nimmegeers, P., Telen, D., Fryer, P. J., Van Impe, J., & Bakalis, S. |title=Effect of chyme viscosity and nutrient feedback mechanism on gastric emptying |journal=Chemical Engineering Science |year=2017 |volume=171 |pages=318–330 |doi=10.1016/j.ces.2017.05.048|pmc=5569601 }}

[[Category:Digestive system]]
[[Category:Body fluids]]