Oesophagus Week 5 FINISHED Flashcards
What is the oesophagus?`
A muscular tube extending between the pharynx and the stomach
How long is the oesophagus?
25cm long
What is the diameter of the oesophagus?
2cm
What is the function of the oesophagus?
To convey food between the pharynx and the stomach
What happens when a food bolus enters the oesophagus?
When a food bolus descends the lumen expands and initiates reflex peristalsis in the inferior 2/3 of the oesophagus
When does the oesophagus lumen look like when its empty?
It has a slit like lumen
What are the 4 constrictions of the oesophagus?
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
What are constrictions of the oesophagus?
Where adjacent structures produce impressions
What are the 2 landmarks where the oesophagus begins? What else happens at this landmark
The inferior cricoid cartilage
C6
This is where the trachea changes to the larynx
Which constriction of the oesophagus is the narrowest? Where is it found?
What muscle causes it?
The Upper oesophageal sphincter
Found at the pharyngoesophageal junction
Caused by cricopharyngeus
What constriction does the oesophagus travel through to pass through the diaphragm?
The lower oesophageal sphincter
What is the cervical pathway of the oesophagus?
- 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
Why does the oesophagus pass through the diaphragm and why is this important?
As we breathe in there is increase intraabdominal pressure. The diaphragm constricts and closes off the oesophagus, preventing regurgitation
What is the thoracic pathway of the oesophagus?
- 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
What are the 2 parts of the mediastinum, what divides it and what happens there?
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
What parts is the inferior mediastinum broken into? Which part does the oesophagus travel through?
Anterior, middle, posterior
Oesophagus travels through the posterior part
What is the abdominal pathway of the oesophagus?
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
What is the arterial supply of the oesophagus?
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)
What is the venous drainage of the oesophagus?
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
What is the nerve supply for the oesophagus?
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
What is the structure of the oesophagus? (layers of muscle orientations)
What type of muscle is in the oesophagus?
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
What type of epithelium is the oesophagus lined with?
Stratified squamous epithelium
