THE DIGESTIVE SYSTEM

An illustrated adventure through the human digestive system.

The subtitle says it all—no organ or, seemingly, molecule goes unexplored, from the oral cavity all the way to the rectum. The protagonist is a bacterium in the oral cavity named E who accidentally leaves the comfort of its natural habitat (where some 50 billion to 100 billion other bacteria reside) when it’s swallowed along with a bolus (or blob of chewed food—one of many vocabulary words defined in context and in a closing glossary). E meets new bacteria, enzymes, and sentient organs along the way who explain their roles in the digestive tract. “My dominion,” explains H. pylori, “is the thick gastric mucosa, or mucous membrane.” As E moves through the digestive system, a diagram that appears periodically continues to grow. Viola’s text clarifies the concepts with the help of Ristaino’s illustrations, which also provide humor, and much of what is introduced is reiterated at other points in the graphic novel, aiding retention. While Viola works hard to break down information, he still packs a lot in: “Saliva contains an enzyme called amylase. Amylase breaks down starch, a complex carbohydrate, into simple sugars….And some saliva carries an enzyme called lipase that starts breaking down triglycerides.” Magic School Bus graduates ready for a busy, heavy informational load will find this just the ticket. The backmatter also includes brief introductions to the digestive systems of cats, dogs, whales, cows, birds, and cockroaches.

A fun and challenging introduction.