Oesophagus Week 5 FINISHED

Question 1

What is the oesophagus?`

Answer 1

A muscular tube extending between the pharynx and the stomach

Question 2

How long is the oesophagus?

Answer 2

25cm long

Question 3

What is the diameter of the oesophagus?

Answer 3

2cm

Question 4

What is the function of the oesophagus?

Answer 4

To convey food between the pharynx and the stomach

Question 5

What happens when a food bolus enters the oesophagus?

Answer 5

When a food bolus descends the lumen expands and initiates reflex peristalsis in the inferior 2/3 of the oesophagus

Question 6

When does the oesophagus lumen look like when its empty?

Answer 6

It has a slit like lumen

Question 7

What are the 4 constrictions of the oesophagus?

Answer 7

1) Upper oesophageal sphincter
- narrowest part of the oesophagus
~ 15 cm from the incisor teeth
- found at the pharyngoesophageal junction
- caused by cricopharyngeus

2) Where the oesophagus is crossed by the arch of aorta
~22.5 cm from the incisor teeth

3) Where crossed by the Left main bronchus
~ 27.5 cm from the incisor teeth

4) Lower oesophageal sphincter
- where it passes through the diaphragm
~ 40 cm from the incisor teeth

Question 8

What are constrictions of the oesophagus?

Answer 8

Where adjacent structures produce impressions

Question 9

What are the 2 landmarks where the oesophagus begins? What else happens at this landmark

Answer 9

The inferior cricoid cartilage
C6

This is where the trachea changes to the larynx

Question 10

Which constriction of the oesophagus is the narrowest? Where is it found?
What muscle causes it?

Answer 10

The Upper oesophageal sphincter

Found at the pharyngoesophageal junction

Caused by cricopharyngeus

Question 11

What constriction does the oesophagus travel through to pass through the diaphragm?

Answer 11

The lower oesophageal sphincter

Question 12

What is the cervical pathway of the oesophagus?

Answer 12

• Begins posterior to the cricoid cartilage
• In the median plane at the inferior margin
• It then inclines slightly to the Lt as it descends
• Lies between the trachea and the cervical vertebral spine
• Rt, cervical pleura
• Lt, thoracic duct between the oesophagus and pleura

Question 13

Why does the oesophagus pass through the diaphragm and why is this important?

Answer 13

As we breathe in there is increase intraabdominal pressure. The diaphragm constricts and closes off the oesophagus, preventing regurgitation

Question 14

What is the thoracic pathway of the oesophagus?

Answer 14

• Passes through the superior mediastinum then to the posterior mediastinum
• Passes posterior to the arch of the aorta
• Posterior to the pericardium and Lt atrium
• Passes through the oesophageal hiatus
  found in the muscular Rt crus at the level of T10
• The oesophagus is attached to the hiatus by the phrenicoesophageal ligaments

Question 15

What are the 2 parts of the mediastinum, what divides it and what happens there?

Answer 15

Superior and inferior
Divided by transverse thoracic plane between angle of louis and T4/T5 IVD
- Trachea divides into primary bronchi
- Arch of aorta
- Pulmonary trunk left and right

Question 16

What parts is the inferior mediastinum broken into? Which part does the oesophagus travel through?

Answer 16

Anterior, middle, posterior

Oesophagus travels through the posterior part

Question 17

What is the abdominal pathway of the oesophagus?

Answer 17

Very short = ~ 1.25 cm long
- Extends from the diaphragm to the orifice of the stomach
and is retroperitoneal
- Covered anteriorly and laterally by peritoneum
- The Rt border is continuous with the lesser curvature of the stomach
- The Lt border is separated from the fundus of the stomach by the cardial notch
- A jagged line is found where the mucosa abruptly changes from oesophageal to gastric
- This is known as the esophagogastric junction
- Just above this line is the oesophageal hiatus which functions as a sphincter

Question 18

What is the arterial supply of the oesophagus?

Answer 18

Cervical part
- Branches from the inferior thyroid arteries

Thoracic part
- Ventral paired branches off the aorta

Abdominal part

• Lt gastric artery (branch of the celiac trunk)
• Lt inferior phrenic artery (us off aorta, may arise from celiac trunk)

Question 19

What is the venous drainage of the oesophagus?

Answer 19

Cervical part
- Inferior thyroid veins

Thoracic part
- Paired branches

Abdominal part

• Into the portal venous system through the Lt gastric vein
• Also into the systemic venous system through the oesophageal veins entering the azygos vein

Question 20

What is the nerve supply for the oesophagus?

Answer 20

Cervical part:
- Upper ½ of cervical oesophagus, recurrent laryngeal nerves, branches of the vagus these lie either side of the oesophagus between it and the trachea
- Lower ½ parasympathetic vagus
Sympathetic cervical ganglion

Thoracic & Abdominal part:

• Vagal trunks
• Greater and lesser splanchnic nerves

PUT SIMPLY SYMPATHETIC - VAGUS

Question 21

What is the structure of the oesophagus? (layers of muscle orientations)

What type of muscle is in the oesophagus?

Answer 21

Internal circular layer of muscle
Externally longitudinal layer of muscle

Superior 1/3 skeletal mm
Middle 1/3 mixture of both skeletal and smooth mm
Inferior 1/3 smooth mm

Question 22

What type of epithelium is the oesophagus lined with?

Answer 22

Stratified squamous epithelium