CSI 8 - Acid Reflux (PRE-READING) Flashcards
What is the oesophagus?
Long fibromuscular tube running from pharynx to stomach
How long is the oesophagus, approximately?
25 cm
Where does the oesophagus start?
Inferior border of cricoid cartilage (C6)
Where does the oesophagus extend to?
The cardiac orifice of the stomach
After beginning in the neck, the oesophagus is continuous superiorly with what?
The laryngeal part of the pharynx (laryngopharynx)
Where does the oesophagus descend downwards into when entering the thorax?
Into the superior mediastinum, positioned between the trachea and the vertebral bodies of T1 to T4
How does the oesophagus enter the abdomen?
Via the oesophageal hiatus at T10
What is the oesophageal hiatus?
Opening in the right crus of the diaphragm
How long approx. is the abdominal portion of the stomach at level of T11?
1.25 cm long
What are the 4 layers of the oesophagus?
Adventitia, muscular layer, submucosa, mucosa
What is adventitia?
outer layer of connective tissue
What are the outer very distal and intraperitoneal portion of the oesophagus covered with instead of adventitia?
Serosa
What is the muscle layer of the oesophagus composed of?
External longitudinal muscle layer and inner layer of circular muscle
What type of external muscle is in the superior third of the oesophagus?
Voluntary striated muscle
What type of external muscle is in the middle third of the oesophagus?
Voluntary striated and smooth muscle
What type of external muscle is in the inferior third of the oesophagus?
Smooth muscle
What is the mucosa layer of the oesophagus?
Non-keratinised stratified squamous epithelium (contiguous with columnar epithelium of the stomach)
How is food transported through the oesophagus?
Peristalsis
What is peristalsis?
Rhythmic contractions of muscles propagating down oesophagus through GI tract
What can the hardening of the muscle layers of the oesophagus cause?
Can interfere with peristalsis and cause difficulty in swallowing (dysphagia)
What is dysphagia?
Difficulty in swallowing
What is the purpose of the 2 oesophageal sphincters?
To prevent entry of air and reflux of gastric contents into the oesophagus
What is the upper oesophageal sphincter?
Anatomical, striated muscle sphincter
Where is the upper oesophageal sphincter?
At junction between pharynx and oesophagus
What muscle produces the upper oesophageal sphincter?
Cricopharyngeus muscle
What is the normal function of the upper oesophageal sphincter?
Normally it is constricted to prevent the entrance of air into the oesophagus
What is the lower oesophageal sphincter?
Physiological/functional sphincter - doesn’t have any specific sphinteric muscle
Where is the lower oesophageal sphincter?
Located in the gastro-oesophageal junction
Where is the gastro-oesophageal junction?
Situated to the left of the T11 vertebra, marked by change from oesophageal to gastric mucosa
What 4 phenomena form the lower oesophageal sphincter?
1) Oesophagus enters stomach at an acute angle
2) Walls of intra-abdominal section of oesophagus are compressed when there’s a positive intra-abdominal pressure
3) Folds of mucosa aid in occluding lumen at junction
4) Right crus of diaphragm has pinch cock effect
What happens to the lower oesophageal sphincter during oesophageal peristalsis?
Sphincter is relaxed to allow food to enter into the stomach
What is the function of the lower oesophageal sphincter at rest?
To prevent reflux of acidic gastric contents into the oesophagus
Where are the 4 physiological constrictions in the lumen of the oesophagus?
A - arch of aorta
B - bronchus
C - cricoid cartilage
D - diaphragmatic hiatus
What is the significance of the 4 constrictions in the oesophagus?
These are the areas where food or foreign objects can get stuck
What are the anterior relations of the oesophagus in the cervical and thoracic region?
- trachea
- left recurrent laryngeal nerve
- pericardium
What are the posterior relations of the oesophagus in the cervical and thoracic region?
- thoracic vertebral bodies
- thoracic duct
- azygous veins
- descending aorta
What are the right side relations of the oesophagus in the cervical and thoracic region?
- pleura
- terminal part of the azygous vein
What are the left side relations of the oesophagus in the cervical and thoracic region?
- subclavian artery
- aortic arch
- thoracic duct
- pleura
What are the anterior relations of the oesophagus in the abdominal region?
- left vagus nerve
- posterior surface of heart
What are the posterior relations of the oesophagus in the abdominal region?
- right vagus nerve
- left crus of the diaphragm
What is Barrett’s oesophagus?
Metaplasia of lower oesophageal squamous epithelium to gastric columnar epithelium
What is Barrett’s oesophagus usually caused by?
Chronic acid exposure - as result of malfunctioning lower oesophageal sphincter
What is the most common symptom of Barrett’s oesophagus?
Long-term burning sensation of indigestion
How can Barrett’s oesophagus be detected?
Via endoscopy of the oesophagus
What percentage of malignancies in the UK care oesophageal carcinomas?
2%
What are the clinical features of oesophageal carcinoma?
- dysphagia
- weight loss
What are the 2 major types of oesophageal carcinoma?
- squamous cell carcinoma
- adenocarcinoma
Where does squamous cell carcinoma occur?
Any place in oesophagus - most common subtype of oesophagus cancer
Where does adenocarcinoma occur?
Lower third of oesophagus - associated with Barrett’s oesophagus (usually originates in metaplastic epithelium)
What 2 circulations does the abdominal oesophagus drain into, forming an anastomosis between the 2?
Systemic and portal circulation
What are oesophageal varices?
Abnormally dilated sub-mucosal veins (in the oesophagus wall)
Lie within anastomosis between systemic and portal circulation drainage from abdominal oesophagus
When are oesophageal varices normally produced?
When pressure in portal system increases beyond normal (portal hypertension)
When does portal hypertension most commonly occur?
Secondary to chronic liver disease, like cirrhosis or an obstruction in the portal vein
What do most patient with oesophageal varices present with?
Haematemesis (vomiting of blood) - varices are predisposed to bleeding
What group of people are at high risk of developing oesophageal varices?
Alcoholics