
The Body's Tiny Defense System
When a sniffle strikes, two curious kids shrink down to meet the body's tiny defenders—white blood cells, antibodies, and more—as they discover how the immune system spots germs and fights them off.
Sigue un aliento de aire en un viaje asombroso, desde la nariz hasta los pulmones y hacia la sangre.
Spanish version coming soon.
This story is not available in Spanish yet. You can keep reading in English, or check back soon for the Spanish PDF and quiz.
Spanish version coming soon.
This story is not available in Spanish yet. You can keep reading in English, or check back soon for the Spanish PDF and quiz.

When a sniffle strikes, two curious kids shrink down to meet the body's tiny defenders—white blood cells, antibodies, and more—as they discover how the immune system spots germs and fights them off.

A bite of lunch launches two curious kids on a wild ride through the body's food tunnel—from teeth to stomach to intestines—as they discover how digestion turns food into fuel.

Two curious kids shrink down to ride along a rushing river inside the body—following blood from the heart through arteries and veins as it delivers oxygen and carries away waste.
Cuando inhalas, el aire viaja por la nariz o la boca, baja por la tráquea y llega a los pulmones. El oxígeno pasa de diminutos sacos de aire llamados alvéolos a la sangre, mientras el dióxido de carbono sale para ser exhalado. Este intercambio de gases alimenta las células de todo el cuerpo.
No written reviews yet.