Your Body's Living Defenses
Discover how your organs, tissues, and trillions of resident microbes work together to keep you alive. Learn the mechanics of physical barriers, internal immune responses, and the microscopic ecosystem running inside you.
Like Duolingo, but for Your Body's Living Defenses. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
A short one: 12 levels across 2 sections, about 24 minutes end to end, roughly 5 days at five minutes a day. It moves through The Frontiers of the Human Ecosystem and Internal Conflict and Recovery. It starts from scratch.
Free forever · No credit card · iPhone & Android
Key ideas in Your Body's Living Defenses
- The outermost skin cells are dead, relatively dry, and slightly acidic, creating a hostile surface for microbial growth
- Skin constantly sloughs off its outer cells, mechanically carrying microbes away before they can anchor and multiply
- Inhaled particles and microbes stick directly to the layer of moist mucus lining the respiratory tract
- Tiny microscopic cellular hairs called cilia beat upward in coordinated waves toward the pharynx
- Once swept to the throat, the mucus is swallowed into digestive acid or cleared by coughing
- Stomach acid has an extremely low pH that rapidly denatures (unfolds) vital microbial proteins
- Most bacteria swallowed with food or saliva are neutralized in the stomach before they can colonize the intestines
- Tears and saliva carry specialized protective enzymes (such as lysozyme) that chemically dismantle bacterial cell walls
- Mucus serves as a physical trap for particulates and microbes
- Stomach fluids use high acidity to denature microbial proteins
- Microbes routinely live on the surface without causing harm until a physical crack, puncture, or deep scrape breaches the epithelial layer
- Dry, cracked skin breaks the continuous physical seal, giving surface bacteria a route into deeper living tissue
- Intact reflexes like blinking or moist nasal airways actively preserve barrier function rather than breaking it
- Trillions of harmless resident bacteria coat the inner surface of the intestines
- Invading pathogens typically need to establish a foothold on tissue before they can cause illness
- By taking up physical space and consuming food sources, resident microbes leave invaders with nowhere to attach and nothing to eat
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 Your Body's Living Defenses 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.
How does constantly shedding dead skin cells help protect you from infection?
Get it right to open this lesson and 11 more in the app.
Where Your Body's Living Defenses takes you
- 1
The Frontiers of the Human Ecosystem
- Mapping the Body's Outer Barriers
- Partnering with the Gut Microbiome
- 2
Internal Conflict and Recovery
- Reading the Signs of Active Defense
- Managing Microbes in Everyday Life
2 sections · 4 units · 12 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
Your Body's Living Defenses 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
Mapping the Human Body
Learn to read human anatomy like a clinical map. Master universal body orientation, follow major blood and nerve pathways, and understand how internal structures interact in health and disease.
How Your Body Works
Decode the daily signals, glitches, and mechanics of the machine you live in. Learn what cramps, breath, and posture actually tell you so you can work with your biology instead of fighting it.
Thinking Like a Doctor
Step into the shoes of a medical student to learn how doctors gather clues, solve diagnostic puzzles, and treat the human body as a complex system.
Mapping the Human Body
Learn to read your own body like a clinical map. Discover how surface landmarks reveal internal organs, how your chest and abdomen are organized, and how spinal nerve highways route sensation.
How Your Body Uses Food
Understand what happens after you swallow. Learn how your cells transform everyday meals into steady energy, repair tissue, and signal genuine fullness.
The Language of Your Body
Learn to interpret the signals your body sends every day. This course covers vital signs, common symptoms, and the biological systems that keep you running.
Start Your Body's Living Defenses today.
Download Tomo, search Your Body's Living Defenses, and play your first lesson in under a minute.