Gastro - Upper GI tract

Question 1

What are the 4 stages of swallowing and describe what happens at each stage?

Answer 1

Stage 0 - oral phase:

- Chewing and saliva prepare bolus
- Both oesophageal sphincters are constricted

Stage 1 - Pharyngeal phase:

- Pharyngeal musculature guids food bolus towards oesophagus 
- Upper oesophageal sphincter opens
- LOS opened by vasovagal reflex

Stage 2 - Upper oesophageal phase:

- Upper sphincter closes
- Superior circular muscle rings contract & inferior rings dilate

Stage 3 - Lower oesophageal phase:
- Lower sphincter closes as bolus passes through

Question 2

What is the effect of a functional disorder of the oesophagus?

Answer 2

Absence of a stricture - dysphagia

Question 3

What are the causes of functional disorders of the oesophagus?

Answer 3

Abnormal oesophageal contraction:
- Hypermotility
- Hypomotility
- Disordered coordination
Failure of protective mechanisms for reflux:
- GastroOesophageal reflux disease (GORD)

Question 4

What is dysphagia?

Answer 4

Difficulty swallowing

Question 5

What is odynophagia?

Answer 5

Pain on swallowing

Question 6

What is regurgitation?

Answer 6

Return of oesophageal contents from above an obstruction

Question 7

What is reflux?

Answer 7

Passive return of gastroduodenal contents to mouth

Question 8

Describe the mechanism of achalasia?

Answer 8

• Loss of ganglion cells in Aurebach’s myenteric plexus in LOS wall
• This leads to reduced activity of inhibitory NCNA neurones
• This means the LOS cannot relax/dilate

Question 9

Describe pneumatic dilatation

Answer 9

• A pneumatic dilator is placed in the oesophagus
• A balloon is then placed in the LOS and is inflated
• Once complete inflation has occurred, everything is removed and flow is restored in the oesophagus

Question 10

What is a Heller’s myotomy?

Answer 10

A surgical procedure:
cut the muscle 6cm on the oesophagus and 3cm onto the stomach to remove the stricture then wrap the fundus of the stomach around the exposed mucosa

Question 11

What is a peroral endoscopic myotomy?

Answer 11

• A muscosal incision in made on the inisde of the oesophagus
• The creation of a submucosal tunnel occurrs
• Then a myotomy occurs, where as much muscle required, is removed
• Then the mucosal incision is closed up endoscopically

Question 12

How does hypomotility occurr?

Answer 12

Neuronal defects result in muscle atrophy of oesophagus, therefore no peristalsis in smooth muscle and hence hypomotility - sphincter pressure is too low

Question 13

Describe disordered coordination of the oesophagus

Answer 13

• Incooardinate contractions of the ring muscles in the oesophagus results in corkscrew oesophagus

Question 14

What vascular anomalies can cause dysphagia and why?

Answer 14

Dysphagia Lusoria:

• Abberant right subclavian artery wraps around behind the oesophagus
• This applies pressure on it and makes it hard to swallow

Double aortic arch:
- The presence of a left and right arch that form a loop around the oesophagus can result in pressure making it difficult to swallow

Question 15

What is the primary management for oesophageal perforations?

Answer 15

Initial:

• NBM
• IV fluids
• Broad sprectrum antibiotics and antifungals
• ITU/HDU level care
• Bloods

Surgical emergency

Question 16

What is an oesophagectomy ?

Answer 16

When the main oesophagus is removed and the stomach is stretched and attached to the first viable part of the oesophagus

Question 17

Describe a sliding hiatus hernia

Answer 17

Part of the stomach pushes through the diaphragm

Question 18

State and describe the different types of gastritis

Answer 18

• Erosive and haemorrhagic gastritits:
  
  • Acute ulcer - gastric bleeding and perforation
• Nonerosive, chronic active gastritis:
  
  • Antrum
  • Infection from helicobacter pylori
• Atrophic (fundal gland) gastritis:
  
  • Fundus
  • Autoantibodies destroy parts of pairetal cells and products of them, causing parietal cell atrophy
  • This results in lower acid levels which can result in G cell hyperplasia and potentially cancer
• Reactive gastritis

Question 19

How is gastric secretion regulated?

Answer 19

Stimulation:

- Neural:
    - ACh: postganglionic transmitter of vagal parasympathetic fibres
- Endocrine:
    - Gastrin (G cells of antrum)
- Paracrine:
    - Histamine (ECL cells and mast cells of gastric wall)

Inhibition:

- Endocrine:
    - Secretin (small intestine)
- Paracrine:
    - Somatostatin (SIH)
- Paracrine & autocrine:
    - PGs (E2 & I2), TGF-alpha & adenosine

Question 20

How is mucosal protection acheived?

Answer 20

1. Mucus film :
   
   • Produced by epithelium
   • Protective barier
2. Bicarbonate secretion:
   
   • Produced by prostaglandins
   • Maintain pH
3. Epithelial barrier:
   
   • Apical layer is strong
   • Can expel H+ ions
4. Mucosal blood perfusion:
   
   • Good blood supply
   • Can easily remove H+ ions

Question 21

What can occur during epithelial repair and wound healing?

Answer 21

Rapid restitution through migration:
- The endothelial cells can flatten and spread across the area of damage/exposure

Can cover defect through cell division

If basement membrane is destroyed:
- Acute wound healing required through normal healing cascade of white cells

Question 22

How does H. Pylori affect the stomach?

Answer 22

The bacteria produced urease which converts urea and H20 into CO2 and NH3 which neutralises gastric acid

Question 23

What are the treatments for ulcers?

Answer 23

PPI’s (Proton pump inhibitors)
H2 blockers

Surgery in extreme cases