Editing Oesophagus (section)

== '''Physiology''' ==

* Swallowing
** Three phases:
*** Oral
**** Elevation of the tongue
**** Posterior movement of the        tongue
**** Elevation of the soft        palate
*** Pharyngeal
**** Elevation of the hyoid
**** Elevation of the larynx
**** Tilting of the epiglottis
*** Oesophageal
**** UOS relaxes, and        peristaltic contractions of the posterior pharyngeal constrictors        propel the bolus into the oesophagus
**** UOS closes, reaching 90mm        Hg pressure, preventing reflux
** Peristalsis
*** Primary - progressive -       move down the oesophagus at 2-4cm/sec
*** Secondary - progressive -       generated by distension or irritation of the oesophagus rather than       voluntary swallowing
*** Tertiary - non-progressive,       non-peristaltic, monophasic or multiphasic. Can occur after voluntary       swallowing or spontaneously between swallows. Unco-ordinated       contractions which are responsible for oesophageal spasm.
** Lower oesophageal sphincter
*** Normally 2-5cm in length,       with a minimum total length of 2cm and at least 1cm of intra-abdominal       length being required for normal functioning
*** Requires vagal-mediated       relaxation to open - occurs 1.5 to 2.5 seconds after pharyngeal       swallowing, and lasts 4-6 seconds
*** Post-relaxation contraction       occurs normally
* Reflux mechanism
** Factors:
*** Adequate pressure and       length
*** Radial symmetry
*** Motility of the oesophagus       and stomach
*** Neurotransmitters, hormones       and peptides all influence tone

[[Category:Anatomy]]