Anatomy of the Oesophagus

The Oesophagus

• The adult oesophagus is a flat, muscular tube that starts proximally at the pharynx (pharyngoesophageal junction) and ends at the stomach (gastroesophageal junction).
• At the level of the diaphragm, the oesophagus is surrounded by collagen and elastic fibres.
• The vagus nerve supplies only parasympathetic innervation to the oesophagus, but below the neck, it carries a mixture of both sympathetic and parasympathetic nerve fibres.

Gastroesophageal Reflux Disease (GORD)

• GORD results from an imbalance between defensive factors protecting the oesophagus and aggressive factors from the stomach content.
• Protective factors include antireflux barriers (LES, crural diaphragm, costal diaphragm, and the angle of His).
• Aggressive factors include gastric acidity, volume, and gastric/duodenal content.
• GORD can be heightened by the ingestion of spicy foods and drinks, pregnancy, smoking, late snacks, and sleeping immediately after eating heavy meals.
• GORD-related chest pain may mimic angina pectoris, but can be differentiated by the duration of pain and response to antacids.

Substances that Affect LES Pressure

• Substances that affect LES pressure include peppermint, chocolate, tomatoes, onions, and alcohol.

Treatment of GORD

• Alginic or sodium alginate suspension (Gaviscon) can be used to treat GORD.
• Non-drug management of GORD includes self-directed learning.

The Stomach

• Acid peptic disorders include peptic ulcer disease (PUD), which affects millions of people worldwide.
• Three major PUDs are Helicobacter pylori PUD, gastric duodenal mucosal ulceration, and nonsteroidal anti-inflammatory drugs-induced (NSAIDs) injury.

Possible Causes of PUD

• Possible causes of PUD include NSAIDs use, dyspepsia, GI bleeding, smoking, alcohol, stress, and psychological factors, and diet.

Manifestations

• Abdominal pain is a common manifestation of PUD, characterized by burning pain localized to the epigastrium, occurring 2-3 hours after meals or at night, and relieved by food or antacids.
• Ulcer complications include bleeding, perforation, and pyloric stenosis (gastric outlet stenosis).

Acid Peptic Disorders - Acid Secretion

• Basal acid (mainly HCl) secretion follows a circadian rhythm, with low secretion in the morning and high at night.
• Cholinergic and histaminergic stimulation are the main determinants of HCl secretion.
• Food ingestion is the principal physiological stimulant of HCl secretion.
• Somatostatin plays an inhibitory role in acid secretion.

Acid Peptic Disorders - Mucosal Defence

• Prostaglandins, nitric oxide, mucous, and bicarbonate (HCO3-) play a role in mucosal defence against hyperacidity.
• Other factors that contribute to mucosal defence include mucosal blood flow, stabilisation of mucosal mast cells and lysosomes, and the effects of gastric motility.