AskDefine | Define chyme

Dictionary Definition

chyme n : a semiliquid mass of partially digested food that passes from the stomach through the pyloric sphincter into the duodenum

User Contributed Dictionary

English

Pronunciation

Noun

chyme
  1. The thick semifluid mass of partly digested food that is passed from the stomach to the duodenum
chyme

Extensive Definition

Chyme is the semifluid mass of partly digested food expelled by the stomach into the duodenum.
Also known as Chymus, is the liquid substance found in the stomach before passing through the pyloric valve and entering the duodenum. It results from the mechanical and chemical breakdown of a bolus and consists of partially digested food, water, hydrochloric acid, and various digestive enzymes. Chyme slowly passes through the pyloric sphincter and into the duodenum, where the extraction of nutrients begins. Depending on the quantity and contents of the meal, the stomach will digest the food into chyme anywhere between 40 minutes and a few hours.
With a pH of around 2, chyme emerging from the stomach is very acidic. To raise its pH, the duodenum secretes a hormone, cholecystokinin (CCK), which causes the gall bladder to contract, releasing alkaline bile into the duodenum. The duodenum also produces the hormone secretin to stimulate the pancreatic secretion of large amounts of sodium bicarbonate, which raises the chyme's pH to 7 before it reaches the ileum. As it is protected by a thick layer of mucus and utilizes the neutralizing actions of the sodium bicarbonate and bile, the duodenum is not as sensitive to highly acidic chyme as the rest of the small intestine.
At a pH of 7, the enzymes that were present from the stomach are no longer active. This then leads into the further breakdown of the nutrients still present by anaerobic bacteria which at the same time help to package the remains. These bacteria also help synthesize Vitamin-B and Vitamin-K.

References

chyme in Bengali: পাকমণ্ড
chyme in Czech: Trávenina
chyme in German: Chymus
chyme in Spanish: Quimo
chyme in French: Chyme
chyme in Italian: Chimo
chyme in Portuguese: Quimo
chyme in Swedish: Chymus
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