How Your Body Fits Together
Discover the brilliant engineering beneath your skin. Learn how your bones, muscles, organs, and nerves connect and collaborate to keep you moving, breathing, and alive.
Like Duolingo, but for How Your Body Fits Together. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
24 levels across 3 sections, about 48 minutes end to end, roughly 10 days at five minutes a day. It moves through The Moving Frame, The Supply Engines, and Control and Protection. It starts from scratch.
Free forever · No credit card · iPhone & Android

Key ideas in How Your Body Fits Together
- Bone is living tissue that constantly breaks down and rebuilds itself
- Regular physical impact and weight-bearing stress prompt bone to rebuild itself denser and stronger
- Without regular physical stress or weight-bearing, bone density gradually thins
- The axial skeleton forms the central axis of the body, encasing vital organs like the brain, heart, and lungs
- The appendicular skeleton consists of the limbs and the girdles attaching them, acting as levers for movement
- The skull and ribs belong to the axial division, while arm and leg bones belong to the appendicular division
- A healthy adult human spine has natural alternating curves rather than forming a straight line
- The gentle S-curve acts like an elastic spring, flexing to dissipate compressive forces from movement
- A straight vertical rod would transmit ground shocks directly into the base of the skull
- The pelvis is shaped like a sturdy, bowl-like basin anchoring the base of the spine
- It collects the downward compressive load of the head, torso, and organs
- It splits and channels that central weight outward through the hip joints and down into each leg
- Spongy bone has a porous, lattice-like interior that shelters red bone marrow
- Red bone marrow is the body's primary factory for manufacturing new blood cells
- It produces oxygen-carrying red blood cells, infection-fighting white blood cells, and clotting platelets
- Muscle tissue can only generate pulling tension by contracting; it cannot push bones away
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 Your Body Fits Together 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.
What happens inside a runner's shin bones as they run regular miles?
Get it right to open this lesson and 23 more in the app.
Where How Your Body Fits Together takes you
- 1
The Moving Frame
- The Living Skeleton
- Muscles and Force
- Joints and Articulation
- 2
The Supply Engines
- The Circulatory Network
- Breathing and Gas Exchange
- Digestion and Filtration
- 3
Control and Protection
- The Nervous Wiring
- Homeostasis and Defense
3 sections · 8 units · 24 levels. Built to play, not to enroll.
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 Your Body Fits Together is taught in the Bestie style: your friend who just gets it. 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.
More Health on Tomo
Anatomy and Physiology for Patient Care
Understand how the human body functions as an interconnected system. Learn the core physiological concepts and organ systems that underpin vital signs, fluid balance, and clinical nursing assessments.
Science for TEAS and HESI
Build the exact scientific foundation needed to score high on pre-nursing entrance exams. Learn high-yield anatomy, cell biology, essential chemistry, and scientific reasoning from square one.
How Muscles Work and Mend
Explore the mechanics of muscular movement, joint stabilization, and tissue recovery. Learn how real-world strains, tears, and impacts occur—and how the body repairs itself back to full strength.
Human Movement and Vitality
Explore the intricate machinery of the human body, from the physics of a perfect squat to the cellular chemistry of the food you eat.
The Human Body: Systems and Survival
A comprehensive journey through human anatomy and physiology, designed for the aspiring medical professional. Learn how the body maintains balance, responds to stress, and functions as a complex biological machine.
How Your Lungs Work
Discover the hidden engine behind every breath. Learn how your body captures air, powers your blood, and how you can use breathing to control your energy and stress.
Start How Your Body Fits Together today.
Download Tomo, search How Your Body Fits Together, and play your first lesson in under a minute.