The Oesophagus and its Disorders
A brief introduction to the structure and functions of the oesophagus
(gross anatomy, the structure and innervation of the upper and lower
oesophageal sphincters, the distribution of striated and smooth muscle
in the oesophageal body, the autonomic
innervation). (See also anatomy sessions).
How the upper oesophageal sphincter opens to allow passage of a
bolus into the oesophageal body
Primary and secondary peristalsis in the oesophageal body and their
functions
The relative involvement of cholinergic (ie. via Ach) and non-
cholinergic, non-adrenergic (n.a.n.c) innervation in the control of tone
of the lower oespophageal sphincter
The effect of the neurotransmitters actylcholine (Ach), vasoactive
intestinal polypeptide (VIP) and nitric oxide (NO) on the lower
oesophageal sphincter
A description of multi-component nature of the anti-reflux barrier in the
region of the gastro-oesophageal junction demonstrating an
appreciation that it is not only due to the lower oesophageal sphincter
A description of aspects of the pathophysiology of 'achalasia' and
gastroesophageal reflux disease (GORD)
The physiological rationale and pharmacological basis for the various
treatment strategies (e.g. lifestyle modification anti-secretory agents)
used for reflux disease will be dealt with in the later lectures on
treatment but they link with this lecture
The potential long term effects of untreated GORD
Anatomy of the Oesophagus
The oesophagus is a fibromuscular tube (25cm in length), that is lined by striated
squamous epithelium.
The oesophagus lies posterior to the trachea and begins at the end of the
laryngopharynx and joins the stomach a few cm from the diaphgram (at the cardiac
orifice).
Its function is to transport food to the stomach (eating gullet), importantly it also
secretes mucus which lubricates food and to neutralise any acid that may come up
from the gut.
If you do not produce enough mucus it can lead to damage to the epithelial structures
of the oesphagus (can lead to Barretts)
, Skeletal muscle surround the upper third of the oesophagus, surrounding the
oesophagus below the pharynx.
Smooth muscle is present in the last portion from the lower oesophageal sphincter,
surrounding the lower two thirds.
The oesophagus has two sphincters:
The upper oesophageal sphincter (UOS) is composed of striated muscle and
constricts to avoid air entering into the oesophagus. This is very important in terms
of its function. The UOS area is a high-pressure zone.
The lower oesophageal sphincter (LOS) lies close to the diaphragm, is composed of
smooth muscle and acts as a flap valve. The LOS is a high-pressure zone and has
intrinsic and extrinsic components.
The intrinsic component is under neurohormonal influence (NO, Ach can control the
level of constriction)
A brief introduction to the structure and functions of the oesophagus
(gross anatomy, the structure and innervation of the upper and lower
oesophageal sphincters, the distribution of striated and smooth muscle
in the oesophageal body, the autonomic
innervation). (See also anatomy sessions).
How the upper oesophageal sphincter opens to allow passage of a
bolus into the oesophageal body
Primary and secondary peristalsis in the oesophageal body and their
functions
The relative involvement of cholinergic (ie. via Ach) and non-
cholinergic, non-adrenergic (n.a.n.c) innervation in the control of tone
of the lower oespophageal sphincter
The effect of the neurotransmitters actylcholine (Ach), vasoactive
intestinal polypeptide (VIP) and nitric oxide (NO) on the lower
oesophageal sphincter
A description of multi-component nature of the anti-reflux barrier in the
region of the gastro-oesophageal junction demonstrating an
appreciation that it is not only due to the lower oesophageal sphincter
A description of aspects of the pathophysiology of 'achalasia' and
gastroesophageal reflux disease (GORD)
The physiological rationale and pharmacological basis for the various
treatment strategies (e.g. lifestyle modification anti-secretory agents)
used for reflux disease will be dealt with in the later lectures on
treatment but they link with this lecture
The potential long term effects of untreated GORD
Anatomy of the Oesophagus
The oesophagus is a fibromuscular tube (25cm in length), that is lined by striated
squamous epithelium.
The oesophagus lies posterior to the trachea and begins at the end of the
laryngopharynx and joins the stomach a few cm from the diaphgram (at the cardiac
orifice).
Its function is to transport food to the stomach (eating gullet), importantly it also
secretes mucus which lubricates food and to neutralise any acid that may come up
from the gut.
If you do not produce enough mucus it can lead to damage to the epithelial structures
of the oesphagus (can lead to Barretts)
, Skeletal muscle surround the upper third of the oesophagus, surrounding the
oesophagus below the pharynx.
Smooth muscle is present in the last portion from the lower oesophageal sphincter,
surrounding the lower two thirds.
The oesophagus has two sphincters:
The upper oesophageal sphincter (UOS) is composed of striated muscle and
constricts to avoid air entering into the oesophagus. This is very important in terms
of its function. The UOS area is a high-pressure zone.
The lower oesophageal sphincter (LOS) lies close to the diaphragm, is composed of
smooth muscle and acts as a flap valve. The LOS is a high-pressure zone and has
intrinsic and extrinsic components.
The intrinsic component is under neurohormonal influence (NO, Ach can control the
level of constriction)
