Gastrointestinal

Duodenum for iron and calcium, jejunum for most nutrients, ileum for B12 and bile salts

A memory aid for where each nutrient is absorbed.

Gut-derived ammonia is converted to urea by the liver; failure allows it to reach the brain

A memory aid for ammonia metabolism and hepatic encephalopathy.

Ghrelin stimulates hunger; leptin, PYY and GLP-1 promote satiety

A memory aid for the hormones controlling hunger and satiety.

Bile salts, phospholipids, cholesterol, bilirubin and bicarbonate

A memory aid for what bile contains and what it does.

High red cell turnover with immature conjugation and enterohepatic recycling

A memory aid for why newborns become jaundiced.

Unconjugated bilirubin is conjugated in the liver, excreted in bile, and converted to urobilinogen

A memory aid for the pathway of bilirubin from haem to stercobilin.

Amylase to oligosaccharides, brush border enzymes to monosaccharides, then transport

A memory aid for the steps of carbohydrate digestion and absorption.

Immune-mediated villous atrophy in the proximal small bowel

A memory aid for the mechanism of malabsorption in coeliac disease.

Absorbs water and electrolytes, ferments fibre, and stores faeces

A memory aid for what the colon does.

Slow transit, outlet obstruction or normal transit with hard stool

A memory aid for the mechanisms of constipation and laxative action.

Rectal distension triggers internal sphincter relaxation, with voluntary external sphincter control

A memory aid for the mechanism of defecation.

Intrinsic enteric plexuses modulated by parasympathetic and sympathetic input

A memory aid for the intrinsic and extrinsic control of the gut.

Emulsification, lipolysis, micelle formation, absorption and chylomicron export

A memory aid for the steps of fat handling in the gut.

Drug absorbed from the gut passes through the liver before reaching the systemic circulation

A memory aid for the first pass effect and how it is bypassed.

Un-ionised drug is absorbed, so weak acids favour the stomach and weak bases the intestine

A memory aid for how gut pH affects drug absorption.

Duodenal fat, acid, hypertonicity and protein all slow emptying

A memory aid for the factors controlling gastric emptying.

Mucus and bicarbonate layer, tight junctions, rapid turnover and good blood flow

A memory aid for how the stomach protects itself from its own acid.

Gastrocolic, enterogastric, gastroileal and intestino-intestinal reflexes

A memory aid for the named reflexes coordinating gut activity.

Acute mesenteric ischaemia affects the small bowel; ischaemic colitis affects watershed colon

A memory aid for the types of intestinal ischaemia.

Gastrin, secretin, cholecystokinin and GIP, each with a distinct trigger

A memory aid for the major gut hormones and their actions.

Fermentation, vitamin synthesis, colonisation resistance and immune education

A memory aid for what the intestinal microbiota does.

Peyer's patches, M cells, lamina propria lymphocytes and secretory IgA

A memory aid for the immune apparatus of the gut.

Sympathetic overactivity, inflammation and opioids inhibit coordinated motility

A memory aid for the mechanism of postoperative ileus.

GLP-1 and GIP are released by the gut and amplify insulin secretion

A memory aid for why oral glucose provokes more insulin than intravenous.

Crohn is transmural and patchy anywhere; colitis is mucosal and continuous from the rectum

A memory aid for the physiological differences between Crohn disease and ulcerative colitis.

About 9 litres enters the gut daily and only 100 ml is lost in stool

A memory aid for the daily fluid load handled by the gut.

Absorbed in the duodenum, controlled by hepcidin acting on ferroportin

A memory aid for the control of iron absorption.

Synthesis, storage, metabolism, detoxification, excretion and immune function

A mnemonic for the major functions of the liver.

Luminal, mucosal or postmucosal failure

A memory aid for localising the cause of malabsorption.

Osmotic, secretory, inflammatory and motility related

A mnemonic for the four mechanisms of diarrhoea.

Cyclical waves of contraction every 90 to 120 minutes between meals

A memory aid for the housekeeping motility of the fasting gut.

Progesterone relaxes smooth muscle, slowing emptying and reducing sphincter tone

A memory aid for the gastrointestinal changes of pregnancy.

Glucose-coupled sodium absorption remains intact even in secretory diarrhoea

A memory aid for why oral rehydration solution works.

Bicarbonate from duct cells under secretin, enzymes from acinar cells under cholecystokinin

A memory aid for the two components of pancreatic juice.

Acetylcholine, gastrin and histamine all converge on the proton pump

A memory aid for the three stimuli of acid secretion and the final common pathway.

Contraction above the bolus and relaxation below it

A memory aid for the reflex that propels intestinal contents.

Cephalic, gastric and intestinal phases

A mnemonic for the three phases of gastric acid secretion.

Low pressure system carrying 75 per cent of hepatic blood flow

A memory aid for the portal venous system and portal hypertension.

Pepsin in the stomach, pancreatic proteases in the duodenum, brush border peptidases last

A memory aid for the sequence of protein digestion.

Hypotonic fluid with amylase, mucins, lysozyme and bicarbonate

A memory aid for what saliva contains and does.

Reduced absorptive surface, rapid transit and loss of specialised ileal function

A memory aid for the consequences of extensive small bowel resection.

Cholecystokinin contracts the gallbladder and relaxes the sphincter

A memory aid for the control of bile delivery to the duodenum.

Splanchnic flow rises by up to 100 per cent for several hours after eating

A memory aid for the circulatory response to a meal.

Oral voluntary, pharyngeal reflex, oesophageal peristalsis

A memory aid for the three phases of swallowing.

Bound by R protein, transferred to intrinsic factor, absorbed in the terminal ileum

A memory aid for the steps of vitamin B12 absorption.

Four inputs converge on the vomiting centre in the medulla

A memory aid for the pathways triggering vomiting.