Oesophagus And Its Disorders Flashcards
What types of muscle is the oesophagus made up of?
Upper third - skeletal muscle
Smooth muscle - lower two third
What are the two oesophageal sphincters?
Upper and lower
What is the upper oesophageal sphincter made up of?
Striated muscle - musculo-cartilaginous structure
Why does the upper oesophageal sphincter constrict?
To avoid air entering the oesophagus
What is the lower oesophageal sphincter made of?
Smooth muscle
What does the lower oesophageal sphincter act as?
A flap valve
What are the two components of the lower oesophageal sphincter?
Intrinsic and extrinsic
What are the muscular formations in the intrinsic component of the lower oesophageal sphincter?
Clasp-like semicircular smooth muscle fibres and sling-like oblique gastric muscle fibres on the left side
What is the clasp like component of the lower oesophageal sphincter activated by?
Myogenic activity
What are the sling-like gastric muscle fibres responsive to in the lower oesophageal sphincter?
Cholinergic innervation
Why is reflux common in infants?
Angle of his is poorly developed
What encircles the lower oesophageal sphincter?
Crural diaphragm muscle- the extrinsic lower oesophageal sphincter component
What happens if the lower oesophageal sphincter components malfunction?
Gastro-oesophageal reflux disease (GORD)
How is the oesophagus innervated?
Cholinergic and non-cholinergic
What molecules cause the intrinsic sphincters to contract?
ACh and substance P
What causes relaxation of the intrinsic sphincters?
NO and VIP
What nerves supply the upper part of the oesophagus?
Somatic motor neurones of the vagus and splanchnic nerves
What is the lower part of the oesophagus innervated by?
Visceral motor neurones of vagus nerve with interruptions
What are the functions of the oesophagus?
Swallowing
Moving food and fluids from pharynx to stomach
What’s a swanky word for swallowing?
Deglutition
What is deglutition triggered by?
Afferent impulses in the trigeminal, glossopharyngeal and vagus nerves
Where do the efferent impulses pass?
To the pharyngeal musculature and the tongue
What are the nerves that supply the tongue?
Trigeminal, facial and hypoglossal
Where are the impulses from the oesophagus integrated into?
Nucleus tractus solitarius, nucleus ambiguous and the dorsal vagal nucleus
What initiates swallowing?
Voluntary action
What are the reflex responses of the oesophagus?
- Inhibition of breathing
- closure of glottis (or vocal cords) by the epiglottis
- ring of peristaltic waves behind the material
- A second peristaltic wave moving any food remnants along
What is oropharyngeal dysphagia caused by?
Upper oesophageal sphincter not being able to open or a disco-ordination of the timing between opening of the UOS and the pharyngeal push behind the ingested bolus
What happens to the upper oesophageal sphincter as soon as the food passes?
Closes
What leads to repeated waves of peristalsis?
The oesophageal receptors being stimulated because of continued dilation
What is the action of the Cardia?
Plug-like by the mucosal folds to block the lumen in the gastro-oesophageal junction
What is the pressure acting on the intra-abdominal parts of the oesophagus?
Abdominal pressure
What is the part of the lower oesophageal sphincter that only adults have?
Valve- like effect of oblique entry into stomach
What is achalasia?
Disorders of motility or peristalsis of the oesophagus
How do you asses achalasia?
Assess the motor function of the UOS, LOS and oesophageal body
What is an oesophageal spasm?
Abnormal oesophageal contractions and food not effectively reaching the stomach
What is a diffuse oesophageal spasm?
When there’s chest pain coming from the oesophagus
What is the prevalence of achalasia?
1 in 100,000
When can achalasia present?
Any age
What are the causes of achalasia?
- Peristaltic disorders of the oesophagus
- nerve damage on the oesophagus
- degenerative lesions on the vagus nerve
- loss of myenteric plexus ganglionic cells in the oesophagus
What is the underlying cause of achalasia?
We don’t know but possibly autoimmune or triggered by infection
What are the symptoms of achalasia?
Dysphagia
Vomiting
Heartburn
What is heartburn?
Retrosternal burning sensation due to oesophageal dismotility
What can heartburn be caused by?
Retention of small quantities of acid refluxed in the oesophagus due to poor emptying and incomplete relaxation of LOS
What tests can be done to diagnose achalasia?
Barium radiography
Oesophageal manometry
What will an achalasic oesophagus look like?
Dilated with a beak deformity at the end
Why do you do oesophageal manometry?
- Determine the cause of non-cardiac chest pain
- find the cause of GORD
- find cause of dysphagia
What does a low LOS pressure suggest?
GORD
Can GORD happen with a normal LOS pressure?
Yes
What does a high LOS pressure suggest?
Achalasia
What are abnormal oesophageal manometry results characterised by?
Muscle spasms in the oesophageal body or weak contractions along the oesophagus
Why is it helpful for reflux to stimulate salivation?
Saliva = natural antacid- dilute and neutralises refluxed stomach contents
What are the causes of GORD (3)?
Normally (98% of time) its transient spontaneous LOS relaxation
Or the resting LOS pressure is too weak to resist pressure within the stomach
Or sudden relaxation of LOS not induced by swallowing
What affects the severity of GORD?
- Weak or uncoordinated oesophageal contractions
- length of time oesophagus is exposed to gastric acid
- amount of pressure placed on the anti-reflux barrier
When does the pressure on the anti-reflux barrier change?
After eating, lying down and when there’s delayed gastric emptying
What are some risk factors associated with GORD?
- Pregnancy, obesity
- fat, chocolate, coffee or alcohol ingestion
- large meals- tomatoes, orange juice and onions
- cigarette smoking
- drugs (anti cholinergic agents, calcium channel blockers and nitrate drugs)
What are symptoms of GORD?
- Heartburn and acid regurgitation
- Disrupted sleep- when reflux irritates the larynx
- dysphagia
What are the four tests for GORD?
- low dose proton pump inhibitor
- upper GI endoscopy
- manometry
- 24hr ambulatory pH monitoring
How does pregnancy induce GORD?
Foetus pushing on abdominal contents-> end of the oesophagus pushed into the thoracic cavity -> forces gastric contents into the oesophagus
What are some long term effects of GORD?
Oesophageal strictures, squamous cell carcinoma, Barretts syndrome, oesophageal ulcers
What are the possible treatments for GORD?
- Lifestyle changes
- anti-reflux surgery
- antacids
- H2 receptor antagonists and proton pump inhibitors
- metaclopramide and domperidone
What lifestyle changes will help with GORD?
- raise the head of the bed at night
- weight loss
- modify food (dec fat intake)
- avoid lying down after meals
