!Esophagus (Gullet)
!!Anatomy overview
The esophagus or gullet consists of a __muscular tube__ through which food passes from the ((Digestive - Pharynx|pharynx)) to the ((Digestive - Stomach Overview|stomach)). In humans, the esophagus is continuous with the laryngeal part of the pharynx at the level of the C6 vertebra. Here we find the upper esophageal sphincter which consists of ((Musculoskeletal - Skeletal Muscles|striated muscle)) and yet, is not under conscious control. During swallowing, the __upper esophageal sphincter__ opens reflexively so the bolus can pass into the esophagus. Food is passed through the esophagus by using the process of peristalsis. Specifically, it connects the pharynx which is the body cavity that is common to the ((Digestive - System Overview|digestive)) and ((Respiratory - System Overview|respiratory systems)) with the stomach  where the second stage of digestion is initiated. 

The esophagus is lined with a __mucous membrane__ consisting of squamous epithelium, and a ((Organ Walls - Submucosa Layer|submucosa)) containing the mucous secreting glands, and connective structures termed papillae.  The epithelium of the oesphagus has a relatively rapid turnover, and serves a protective function due to the high volume transit of food, saliva and mucus.

While historically the ((Digestive - Esophagus Mucosa (lower part) and LES|gullet mucosa)) derived from gut mucosa with secretory and reabsorptive functions, it was later covered and replaced by ((Digestive - Esophagus - Ectodermal Mucosa (upper part)|ectodermal tissue)) governed by the cerebral cortex in the __upper 2/3 __of the organ. Here, we also find a layer of ((Digestive - Esophagus - Muscle layer|striated muscle)). The __lower part__ is lined with smooth muscle, that acts through peristaltic action to move swallowed food down to the stomach. The swallowing sound that we hear is the esophagus at work. The esophagus ends at the mouth of the upper stomach with a __functional sphincter__ (not muscle tissue), avoiding that gastric juice enters and damages esophagus mucosa.

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!!Brain
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!!!Relay:
__Brain Stem__ (+/-) dorsal right: for ((Digestive - Esophagus Mucosa (lower part) and LES|Endodermal Mucosa)) (Lower 1/3 of the gullet) and Cardiac sphincter, and
__Midbrain__ (+/-) dorsal right: for ((Digestive - Esophagus - Muscle layer|Smooth muscle layer)) (Smooth organ muscle, lower half of the gullet)
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__Cerebral Medulla__ (-/+) "thoracic area" left & right: for ((Digestive - Esophagus - Muscle layer|Striated muscle ))and ((Organ Walls - Submucosa Layer|Submucosa))/((Musculoskeletal - Connective Tissue|Connective Tissue))
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__Cerebral Cortex__ (-/+) insular region medial left & right below coronary relays: for ((Digestive - Esophagus - Ectodermal Mucosa (upper part)|Ectodermal Mucosa ))(Upper 2/3 of the gullet)
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