Stomach

Function

The stomach is a 1–1.5 L muscular blender. Its three muscle layers (longitudinal, circular and oblique — unique in the gut) churn food into chyme while 2–3 million gastric pits secrete hydrochloric acid at pH 1.5–3.5, pepsinogen, intrinsic factor and mucus.

The fundus' parietal cells acidify and the antrum's G cells orchestrate: gastrin cranks acid, histamine amplifies it, somatostatin brakes it. A meal leaves through the pylorus in 2–4 hours, liquids first, fats slowest. The stomach absorbs little but alcohol and aspirin — the rest passes on for the small bowel's 6 m of absorption.

Blood supply

Left and right gastric, gastro-omental and short gastric arteries (all from the coeliac trunk).

Nerve supply

Vagus (parasympathetic secretomotor and motility), coeliac plexus sympathetic.

Clinical relevance

Peptic ulcer

H. pylori or NSAIDs breach the mucosal armour — burning epigastric pain; posterior ulcers erode the gastroduodenal artery.

Gastric cancer

Early gastric cancer is silent; screening in high-incidence countries catches it when endoscopic resection cures.

Pyloric stenosis

Infantile hypertrophy of the pylorus projects non-bilious projectile vomiting at 6 weeks — the olive-shaped mass.

Related conditions

• Gastro-oesophageal reflux disease
• Peptic ulcer disease
• Gastritis
• Stomach cancer
• Gastroenteritis
• Vitamin B12 deficiency (pernicious anaemia)