Oesophagus Flashcards
desribe the muscle type in different parts of the oesophagus
Superior third – voluntary striated muscle
Middle third – voluntary striated and smooth muscle
Inferior third – smooth muscle
desribe the structure of the oesophahus
consists of an internal circular and external longitudinal layer of muscle
how is food transported through the oesophagus
by peristalsis
what is perstalsis
a rhythmic contractions of the muscles, which propagates down the oesophagus
how can disphagia come about
Hardening of these muscular layers can interfere with peristalsis and cause dysphagia – difficulty in swallowing.
in the thoracic part of teh oesophagus what is anter and what is posterior
Ant
Trachea
Left recurrent laryngeal nerve
Pericardiuum
Post Thoracic Verterbral bodies Throacic duct Azygous veins Desending aorta
in the thoracic part of teh oesophagus what is anter and left and what is right
Right
Pluera
Terminal part of the azygous vein
Left Subclaviatien artery Aortic arch Thoaccic duct Pleura
in the abdominal part of teh oesophagus what is anter and what is posterior
Ant. Left vagus
Post surface of teh heart
Post
Right vagus
Left crus of the diaphragm
arterial blood supply of the thoracic oesophagus
branches of the thoracic aorta and the inferior thyroid artery (a branch of the thyrocervical trunk).
lympatics of each part of the oesophagus
The lymphatic drainage of the oesophagus is divided into thirds:
Superior third – deep cervical lymph nodes.
Middle third – superior and posterior mediastinal nodes.
Lower third – left gastric and celiac nodes.
venous drainage of the thoracic oesophagus
Venous drainage into the systemic circulation occurs via branches of the azygous veins and the inferior thyroid vein.
arterial supply of the abdominal oesophagus
The abdominal oesophagus is supplied by the left gastric artery (a branch of the coeliac trunk) and left inferior phrenic artery.
venous drainage of the abdominal oesophagus
To the portal circulation via left gastric vein
To the systemic circulation via the azygous vein.
what do the portal circulation and systemic circulation form
a porto-systemic anastomosis, a connection between the portal and systemic venous systems
what is the function of the two oesophageal spheniter
they act to prevent the entry of air and the reflux of gastric contents respectively
descibe the upper oesophageal sphinter
The upper sphincter is an anatomical, striated muscle sphincter at the junction between the pharynx and oesophagus. It is produced by the cricopharyngeus muscle. Normally, it is constricted to prevent the entrance of air into the oesophagus.
describe the lower oesophageal sphinter
The lower oesophageal sphincter is a physiological sphincter located in the gastro-oesophageal junction (junction between the stomach and oesophagus). The gastro-oesophageal junction is situated to the left of the T11 vertebra, and is marked by the change from oesophageal to gastric mucosa.
The oesophagus enters the stomach at an acute angle.
The walls of the intra-abdominal section of the oesophagus are compressed when there is a positive intra-abdominal pressure.
The folds of mucosa present aid in occluding the lumen at the gastro-oesophageal junction.
The right crus of the diaphragm has a “pinch-cock” effect.
why is the pyloric sphinter classed
as it does not have any specific sphincteric muscle. Instead, the sphincter is formed from four phenomena:
what happens to the lower oesophageal sphincter during oesophagueal perstalsis vs rest
During oesophageal peristalsis, the sphincter is relaxed to allow food to enter the stomach. Otherwise at rest, the function of this sphincter is to prevent the reflux of acidic gastric contents into the oesophagus.
structure of the oesophagus function and eathway
fibromuscular tube, approximately 25cm in length, that transports food from the pharynx to the stomach. It originates at the inferior border of the cricoid cartilage, C6, extending to the cardiac orifice of the stomach, T11.
what is the oesophagus continuous with
laryngeal part of the pharynx.
path of the oesophagus
The oesophagus originates in the neck, at the level of the sixth cervical vertebrae. It is continuous with the laryngeal part of the pharynx.
It descends downward into the superior mediastinum of the thorax. Here, it is situated between the trachea and the vertebral bodies T1 to T4. It then enters the abdomen by piercing the muscular right crus of the diaphragm, through the oesophageal hiatus (simply, a hole in the diaphragm) at the T10 level.
what is the phenoesophageal ligament
connects the oesophagus to the border of the oesophageal hiatus. This permits independent movement of the oesophagus and diaphragm during respiration and swallowing.
