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Your Body, System by System
Learn how your body is built and kept alive: the skeleton and muscles that move you, the heart, lungs and gut that fuel you, and the brain and senses that run it all.
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- 1
Life & Biology
What Is Life? The Cell
Everything alive is made of cells, tiny bags of chemistry that eat, grow, copy themselves and die. You are a cooperative of about 37 trillion of them.
4 min read 4-question quiz
- 2
The Human Body
The Skeleton and Bones
Your 206 bones are living tissue: they grow, heal, make your blood and rebuild themselves completely every decade. Here is the frame you are built on.
5 min read 5-question quiz
- 3
The Human Body
Muscles
Six hundred muscles move you, pump your blood and push your food along. Every one of them works the same way: by pulling, never pushing.
4 min read 4-question quiz
- 4
The Human Body
The Heart and Blood
A fist-sized pump pushes five litres of blood around 100,000 kilometres of vessels every minute. Here is the river that keeps every cell alive.
4 min read 4-question quiz
- 5
The Human Body
Lungs and Breathing
Twenty thousand times a day you draw in air and your lungs, with a surface the size of a tennis court, pass oxygen into your blood. Here is how breathing works.
4 min read 4-question quiz
- 6
The Human Body
Digestion
A nine-metre tube turns a sandwich into the molecules that build and fuel you, with help from acids, enzymes and trillions of bacteria.
4 min read 4-question quiz
- 7
The Human Body
The Immune System
An army of trillions of cells defends you against invaders you never notice, learns from every battle and remembers for decades. Vaccines train it; sometimes it turns on you.
4 min read 4-question quiz
- 8
The Human Body
Skin, Hair and Nails
Your skin is your largest organ: a waterproof, self-repairing shield that senses touch, controls your temperature and makes vitamin D. Hair and nails grow from it.
3 min read 4-question quiz
- 9
The Human Body
The Brain
A kilo and a half of soft tissue containing 86 billion neurons and more connections than there are stars in the galaxy. It is reading this, and it is the most complex object known.
4 min read 4-question quiz
- 10
The Human Body
The Senses
Sight, hearing, smell, taste and touch are the body's instruments for turning light, vibration and chemistry into experience. There are more than five, and all of them are built in the brain.
4 min read 4-question quiz
- 11
The Human Body
Sleep and Dreams
We spend about a third of our lives asleep. Far from switching off, the brain uses that time to store memories, clean itself and reset the body.
3 min read 4-question quiz
