Retching
Encyclopedia
Retching is a process in the human body where gastric
(and sometimes duodenal
) contents are forced into the esophagus
but do not enter the pharynx
. Retching usually precedes vomiting
, when the upper esophageal sphincter
remains closed. If the upper esophageal sphincter is open, vomiting
occurs. It can also be caused by a bad smell or choking. Retching involves a deep inspiration against a closed glottis. This, along with contraction of the abdomen, leads to a pressure difference between the abdominal and thoracic cavities. As a result, the stomach and gastric contents are displaced upwards toward the thoracic cavity.
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
(and sometimes duodenal
Duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...
) contents are forced into the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...
but do not enter the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
. Retching usually precedes vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, when the upper esophageal sphincter
Upper esophageal sphincter
The upper esophageal sphincter refers to the superior portion of the esophagus.Unlike the lower esophageal sphincter, it consists of striated muscle and yet, is not under conscious control. Opening of the UES is triggered by the swallow reflex...
remains closed. If the upper esophageal sphincter is open, vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
occurs. It can also be caused by a bad smell or choking. Retching involves a deep inspiration against a closed glottis. This, along with contraction of the abdomen, leads to a pressure difference between the abdominal and thoracic cavities. As a result, the stomach and gastric contents are displaced upwards toward the thoracic cavity.