Gastrointestinal
Motility, secretions, gut hormones, digestion, absorption and the liver.
23 pages
Exam priority: high
- Bile and the enterohepatic circulationMechanism · The liver makes bile to emulsify fat; almost all bile salts are reabsorbed in the ileum and…
- Carbohydrate digestion and absorptionMechanism · Starch and sugars are cut down to glucose, galactose and fructose; only those monosaccharides…
- Fat digestion and absorptionMechanism · Bile disperses fat, lipase cuts it, micelles carry it to the wall, and it leaves the gut packed…
- Gastric acid secretionMechanism · Parietal cells pump acid into the stomach with the H⁺/K⁺ pump; the vagus, gastrin and histamine…
- Gastrointestinal hormonesTable to know · The gut makes its own hormones: they report what food arrived and tune acid, enzymes, bile…
- Mucus and mucosal protection in the gutMechanism · A slippery, alkaline gel and a fast-healing lining let the gut hold acid and enzymes without…
- Water and electrolyte absorption and how diarrhea happensMechanism · The gut handles about 9 L of fluid a day and returns nearly all of it to the blood by following…
Exam priority: medium
- Absorption of iron, calcium and vitamin B12Mechanism · Iron and calcium are absorbed mainly in the duodenum; vitamin B12 needs intrinsic factor from…
- Exocrine pancreatic secretionMechanism · The pancreas sends bicarbonate to the duodenum to neutralize acid, and enzymes that digest…
- Functions of the liverConcept · The liver processes what is absorbed, makes blood proteins, stores energy, clears toxins and…
- Gastric motility and emptyingMechanism · The stomach stores food, grinds it and hands it to the duodenum in small portions, at the pace…
- Hepatic lymph, the liver as a blood reservoir, and how ascites formsMechanism · The liver's leaky sinusoids make lots of protein-rich lymph; when their pressure rises and the…
- Protein digestion and absorptionMechanism · Proteins are cut in the stomach and duodenum down to amino acids and short peptides, which the…
- Small bowel and colon motilityMechanism · The gut mixes its contents with segmenting contractions and moves them on with peristalsis; the…
- Splanchnic and portal circulationRegulation · Blood from the gut, spleen and pancreas passes through the liver first via the portal vein; it…
- Swallowing and esophageal motilityMechanism · Swallowing starts voluntarily and continues as an automatic reflex that seals the airway and…
- The colon: salvage absorption, gut bacteria, gas and stoolConcept · The colon dries the stool, its bacteria ferment fibre into fuel and gas, and bile pigments…
- The enteric nervous system, slow waves and GI controlRegulation · The gut has its own network of neurons: it sets the rhythm, mixes and pushes contents; the vagus…
- Vomiting and its controlRegulation · Vomiting is a protective brainstem reflex that expels stomach contents; losing a lot of acid…
For completeness
- Defecation and continenceRegulation · When stool fills the rectum, a reflex opens the internal sphincter; the voluntary external…
- How digestive glands secrete and what switches them onConcept · Digestive glands package enzymes in granules and pump chloride to pull water out; touch, nerves…
- Patterns of malabsorptionMechanism · Malabsorption happens when luminal digestion, the absorbing mucosa or the lymphatic exit fails…
- Salivary secretionMechanism · The salivary glands make 1 to 1.5 L of saliva a day to moisten food, start starch digestion and…
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Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Representative model, for educational purposes only.