How the Human Body Works
Discover how your organs, tissues, and fluids coordinate every second of the day. Learn the elegant mechanics behind how you move, breathe, fight disease, and stay alive.
Like Duolingo, but for How the Human Body Works. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
26 levels across 3 sections, about 52 minutes end to end, roughly 10 days at five minutes a day. It moves through Movement and Vital Rhythms; Processing, Cleansing, and Defense; and Coordination and Internal Balance. It starts from scratch.
Free forever · No credit card · iPhone & Android
Key ideas in How the Human Body Works
- Bone is living tissue that constantly breaks down and rebuilds its mineral structure
- Physical resistance and bearing weight signal bone cells to lay down more mineral and increase density
- Without regular load or gravity, bone tissue is absorbed faster than it rebuilds, becoming thinner and weaker
- Muscle fibers can only exert mechanical force by contracting—they pull, they cannot push
- To return a bent limb to its original position, an opposing muscle on the opposite side of the joint must contract to pull it back
- Joints rely on paired antagonistic muscles, like the biceps and triceps, to create back-and-forth movement
- Tendons connect muscle to bone, translating muscle contractions into joint motion
- Ligaments connect bone to bone, acting as tough straps that limit unwanted movement and stabilize joints
- A tendon moves a joint when muscle pulls, while a ligament resists joint dislocation
- Cartilage forms a smooth, slippery buffer on the ends of bones to absorb impact and reduce friction
- Unlike bone, cartilage lacks its own network of blood vessels
- Nutrients must slowly diffuse into cartilage from surrounding joint fluid, making tissue repair and healing sluggish
- Standing upright is an active balancing act against gravity, not a passive mechanical lock
- Postural muscles in the calves, thighs, and back make continuous micro-contractions to steady your center of gravity
- If a person loses consciousness, the lack of muscle contraction causes them to collapse immediately because the skeleton cannot stand on its own
- The right side of the heart pumps oxygen-depleted blood a short distance to the delicate lungs
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives How the Human Body Works the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
Imagine an athlete lifting weights every day. How do their bones respond to that heavy work?
Get it right to open this lesson and 25 more in the app.
How to learn How the Human Body Works, step by step
Go in order. 26 short levels across 3 sections, about 52 minutes in all, five minutes a day.
- 1
Movement and Vital Rhythms
- The Living Framework: Bones and Muscles
- The Pressure Engine: Blood and Circulation
- Breath and Gas Exchange: The Respiratory System
- 2
Processing, Cleansing, and Defense
- Fuel Processing and Filtration: Digestion and Kidneys
- Barriers and Defense: Skin and the Immune System
- 3
Coordination and Internal Balance
- Instant Signals: The Nervous System and Senses
- Chemical Broadcasts: The Endocrine System
- The Master Balance: Homeostasis
3 sections · 8 units · 26 levels. Built to play, not to enroll.
Questions about How the Human Body Works
How do I learn How the Human Body Works?
Go in order: start with Movement and Vital Rhythms, then Processing, Cleansing, and Defense, then Coordination and Internal Balance. On Tomo that's 26 short levels, about 52 minutes in all, played five minutes a day. Start free and play the first level in under a minute.
Is there a Duolingo-style app for How the Human Body Works?
Yes. Tomo works like Duolingo: short daily lessons, streaks and quick quizzes. How the Human Body Works is one of its free courses, and you can type any other topic to get a course of your own.
Is the How the Human Body Works course free?
Yes. How the Human Body Works is playable on Tomo's free plan, which doesn't expire. No credit card, no waitlist. Download the app and start your first lesson.
How long does it take to learn How the Human Body Works?
26 levels across 3 sections, about 52 minutes of play in total. It's built for five minutes a day, so you finish it a little at a time instead of all at once.
Do I need any background to start How the Human Body Works?
No. It's pitched at a beginner level, so it starts where you are and builds up. If you can tap a phone, you can start.
Tomo is in ChatGPT
Tomo is also a ChatGPT plugin: the same playable courses, built and played inside your chat.
Add Tomo to ChatGPT- What to ask
- “Make me a Tomo course on black holes.” “Turn this chat into a Tomo course.”
- What you get
- Quick questions with instant feedback, hearts and stars, ready to play in about a minute.
- Where it goes
- No sign-up to start. Connect your Tomo account and your streak carries on in the app.
You pick the voice
How the Human Body Works is taught in the Storyteller style: every lesson is a story. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start How the Human Body Works today.
Download Tomo, search How the Human Body Works, and play your first lesson in under a minute.