Editing Chyme (section)

{{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 that is expelled by the [[stomach]], through the [[pyloric valve]], into the [[duodenum]]<ref>{{cite Merriam-Webster|chyme}}</ref> (the beginning of the [[small intestine]]).<ref>{{cite encyclopedia |title=Chyme |url=https://britannica.com/science/chyme |encyclopedia=[[Encyclopædia Britannica]] |language=en |access-date=2025-01-25}}</ref>

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 |last=Hemmings |first=Hugh C. |url=https://books.google.com/books/about/Pharmacology_and_Physiology_for_Anesthes.html?id=am_DS7rgypAC#v=snippet&q=chyme%20is%20highly%20acidic&f=false |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 secretes a [[hormone]], [[cholecystokinin]] (CCK), which causes the [[gall bladder]] to contract, releasing alkaline [[bile]] into the duodenum. CCK also causes the release of digestive enzymes from the [[pancreas]]. The duodenum is a short section of the small intestine located between the stomach and the rest of the small intestine. 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. The chyme moves through the [[jejunum]] and the [[ileum]], where digestion progresses, and the non-useful portion continues onward into the [[large intestine]]. The duodenum is protected by a thick layer of [[mucus]] and the neutralizing actions of the sodium bicarbonate and bile.

At a pH of 7, the enzymes that were present from the stomach are no longer active. The breakdown of any nutrients still present is by [[anaerobic bacteria]], which 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.