Mucosa    Stratified squamous epithelium: a flatten surface with a few keratohyalin granules,
                        but not cornified; just a little above the cardia( Zigzag line or Z-Z line ) an abrupt
                    transition takes place between the statified squamous epithelium of the esophagus
                        and the columnar epithelium of the stomach

Submucosa     The submucosa is quite dense and contains both elastic and collagen fiber.  The
                        submucosa contains Meissner's plexus and some blood vessels

Muscularis     An inner layer ( circular layer ) and outer longitudinal layer with thin layer of
                    connective tissue, in which embedded the myenteric plexus of Auerbach.

Adventitia      A loose connective tissue connecting the esophagus to its surrounding structure

Glands     Two types of glands : esophageal glands proper ( deep glands) and cardiac glands
                  ( superficial glands ) are found below the level of the cricopharyngeus muscle and
                        just above the cardia.
                        The deeper glands are small racemose glands of mucous type, their ducts penetrate
                        the muscularis mucosae located in the submucosa
                        The superficial glands are located in the lamina proper ( tunica propria ) not in the
                        submucosal layer,
 
 
 

Innervation         Contain efferent and afferent fibers → impulse to and from the vessels, glands
                            and muscular and mucus coats of the viscus

Parasympathetic  Are carried in the vagus nerves, the parasympathetic fibers supplying the
                        striated mm. in the pharynx and upper part of the esophagus.  The vagi
                            intercommunicate with the filaments from the paravetebral sympathetic trunks
                            and their branches, so as neck downward, they are really mixed
                        parasympathetic-sympathetic nerves.

                            In the neck, esophagus received twings from the recurrent laryngeal nerves 

                          run upward on each side in the grooves between esophagus and trachea. 

                           On the right side,  it winds below subclavian  artery and combinds vagus nerve.
                           On the left side, it curves beneath the aortic arch combinding vagus returns upward.                                 

                            In the thoracic esophagus, in the superior mediastinum receives impulse from
                            the left recurrent laryngeal nerve and vagus nerve; in the hilum, vagus gives
                            off branches unite with the sympathetic trunks to form pulmonary plexus
                            ( the smaller anterior and larger posterior ).  Below the lung roots, the vagus
                            usually break up into 2 to 4 branches, closely apposed to the esophagus.
   

Sympathetic       Located mainly in th 4th to 6th thoracic segments of the spinal cord.  The
                        preganglionic fibers emerge in the anterior spinal nerve roots as their parent
                            cell.  They mixed rami communicants and pass to paravertebral sympathetic
                            ganglionated trunks.

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