The Digestive System
A nine-metre journey turns food into fuel. Follow a meal from mouth to intestine and meet the organs that break it down…
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Anatomy Category
Digestion & Organs
From the first bite to energy for every cell — the digestive tract and the hard-working liver, stomach and kidneys.
Guides
Guides in Digestion & Organs
Start with any guide below — each one is written for beginners and builds on the last.
Stomach Function
A muscular acid bath that begins protein digestion. How the stomach protects itself, mixes food and signals fullness.
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Liver Function
Your body's 500-job chemical plant. How the liver filters blood, stores energy, makes bile and processes almost…
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Kidney Function
Two fist-sized filters clean your entire blood supply many times a day. How the kidneys balance water, salt and waste.
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Metabolism Explained
Metabolism is every chemical reaction that keeps you alive. What "fast" and "slow" really mean, and how the body turns…
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Practice
Related tools
Reinforce what you learn with these interactive tools.
Planner
Nutrition Planner
Build a simple, balanced day of meals and see an educational breakdown of macronutrients.
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Calculator
Daily Calorie Estimator
Estimate daily energy needs from BMR and activity level to understand how the body budgets energy.
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Reference
Anatomy Glossary
A searchable, plain-language glossary of the anatomy terms used across the site.
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Related articles
Deeper dives and fascinating facts from the blog.
Digestion Basics: From First Bite to Fuel
What happens to a sandwich after you swallow it? Follow food on its nine-metre journey through the digestive system.
Liver Facts: The Organ That Does 500 Jobs
The liver filters blood, stores energy and can even regrow. A closer look at the body's hardest-working chemical plant.
Kidney Facts: Your Body's Two Master Filters
Your kidneys filter your entire blood supply about 40 times a day. Here is how these fist-sized organs keep you balanced.
Explore another body system
Every part of the body connects to the rest. Browse all nine categories and keep exploring.