Oesophagus

Question 1

desribe the muscle type in different parts of the oesophagus

Answer 1

Superior third – voluntary striated muscle
Middle third – voluntary striated and smooth muscle
Inferior third – smooth muscle

Question 2

desribe the structure of the oesophahus

Answer 2

consists of an internal circular and external longitudinal layer of muscle

Question 3

how is food transported through the oesophagus

Answer 3

by peristalsis

Question 4

what is perstalsis

Answer 4

a rhythmic contractions of the muscles, which propagates down the oesophagus

Question 5

how can disphagia come about

Answer 5

Hardening of these muscular layers can interfere with peristalsis and cause dysphagia – difficulty in swallowing.

Question 6

in the thoracic part of teh oesophagus what is anter and what is posterior

Answer 6

Ant
Trachea
Left recurrent laryngeal nerve
Pericardiuum

Post
Thoracic
Verterbral bodies 
Throacic duct
Azygous veins 
Desending aorta

Question 7

in the thoracic part of teh oesophagus what is anter and left and what is right

Answer 7

Right
Pluera
Terminal part of the azygous vein

Left 
Subclaviatien artery
Aortic arch
Thoaccic duct
Pleura

Question 8

in the abdominal part of teh oesophagus what is anter and what is posterior

Answer 8

Ant. Left vagus
Post surface of teh heart

Post
Right vagus
Left crus of the diaphragm

Question 9

arterial blood supply of the thoracic oesophagus

Answer 9

branches of the thoracic aorta and the inferior thyroid artery (a branch of the thyrocervical trunk).

Question 10

lympatics of each part of the oesophagus

Answer 10

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.

Question 11

venous drainage of the thoracic oesophagus

Answer 11

Venous drainage into the systemic circulation occurs via branches of the azygous veins and the inferior thyroid vein.

Question 12

arterial supply of the abdominal oesophagus

Answer 12

The abdominal oesophagus is supplied by the left gastric artery (a branch of the coeliac trunk) and left inferior phrenic artery.

Question 13

venous drainage of the abdominal oesophagus

Answer 13

To the portal circulation via left gastric vein

To the systemic circulation via the azygous vein.

Question 14

what do the portal circulation and systemic circulation form

Answer 14

a porto-systemic anastomosis, a connection between the portal and systemic venous systems

Question 15

what is the function of the two oesophageal spheniter

Answer 15

they act to prevent the entry of air and the reflux of gastric contents respectively

Question 16

descibe the upper oesophageal sphinter

Answer 16

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.

Question 17

describe the lower oesophageal sphinter

Answer 17

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.

Question 18

why is the pyloric sphinter classed

Answer 18

as it does not have any specific sphincteric muscle. Instead, the sphincter is formed from four phenomena:

Question 19

what happens to the lower oesophageal sphincter during oesophagueal perstalsis vs rest

Answer 19

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.

Question 20

structure of the oesophagus
function
and eathway

Answer 20

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.

Question 21

what is the oesophagus continuous with

Answer 21

laryngeal part of the pharynx.

Question 22

path of the oesophagus

Answer 22

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.

Question 23

what is the phenoesophageal ligament

Answer 23

connects the oesophagus to the border of the oesophageal hiatus. This permits independent movement of the oesophagus and diaphragm during respiration and swallowing.