Upper GI Tract Flashcards
(99 cards)
How does the upper oesophageal sphincter open vs the lower oesophageal sphincter?
UOS = reflexively
LOS = by vasovagal reflex (receptive relaxation reflex)
What are the anatomical contributors from the upper GI tract to the lower oesophageal sphincter?
Is the 3-4 cm distal oesophagus within abdomen
• diaphragm surrounds LOS (Lt & Rt crux)
• intact phrenoesophageal ligament
• angle of His
Intraabdominal pressure
what type of muscle makes up the lower thoracic oesophagus/ oesophageal junction?
Smooth muscle
At what vertebral level is the angle of His found?
T10
What are the four stages of swallowing?
Stage 0: oral phase
Stage 1: pharyngeal phase
Stage 2: upper oesophageal phase
Stage 3: lower oesophageal phase
What happens during stage 0 of swallowing?
How is the motility of the oesophagus determined?
determined by pressure measurements (manometry)
• peristaltic waves ~ 40 mmHg
• LOS resting pressure ~ 20 mmHg
> ↓<5 mmHg during receptive relaxation
How is motility of the oesophagus mediated?
mediated by inhibitory noncholinergic nonadrenergic (NCNA) neurones of myenteric plexus
What are the common functional disorders of the oesophagus?
Absence of a stricture
• Abnormal oesophageal contraction
> Hypermotility
> Hypomotility
> Disordered coordination
• Failure of protective mechanisms for reflux
> Gastro-oesophageal reflux disease (GORD)
What is dysphagia? Why are the 2 descriptive terms for localisation?
Difficulty swallowing
Localisation is important - cricopharyngeal sphincter or distal
What is odynophagia?
Pain on swallowing
Define regurgitation
Regurgitation = return of oesophageal contents from above an obstruction
> may be function or mechanical
Define reflux
Reflux = passive return of gastroduodenal contents to the mouth
What causes achalasia?
Loss of ganglion cells in Aurebachs myenteric plexus in LOS wall causing decreased activity of inhibitory NCNA neurones
What is the aetiology behind primary achalasia?
Unknown
What is the aetiology behind secondary achalasia?
Diseases causing oesophageal motor abnormalities similiar to primary achalasia
What effect does achalasia have on the resting pressure of the LOS?
Increased
What are 3 examples of secondary achalasia?
Chagas’ disease
Protozoa infection
Amyloid/sarcoma/eosinophilic oesophagitis
outline the 8 steps of the proposed model of achalasia pathophysiology
Proposed model of achalasia pathophysiology
1. environmental trigger - chronic infections
2. genetic predisposition
3. first stagenon-autoimmune inflammatory infiltrates
4. promotes would repair and fibrosis
5.loss of immunological toleranceleads to autoimmune inflammatory infiltrates
6. apoptosis of neurones
7. humoral response - autoimmune
8. all leads to myenteric neurone abnormalities
What are the symptoms of achalasia?
Retrosternal pain, weight loss, dilated oesophagus, aperistalsis, bird beak in barium swallow, increased LOS pressure
what is aperistalsis?
Absence of peristalsis- radially symmetrical contraction and relaxation of muscles
What are the two most common complications of achalasia?
Oesophagitis, aspiration pneumonia
Give an example of oesophageal hypermotility
Achalasia
Give an example of oesophageal hypomotility
Scleroderma