The Human Microbiome Belongs in A&P

Why this essential story shouldn’t be left entirely to other biology courses.

In my previous post, The Human Microbiome Was There All Along, I briefly outlined the story of how we developed the new Chapter 49: Human Microbiome for the 12th Editon of Anatomy & Physiology. But the more important story, I think, is WHY we added this chapter. 

Is your microbiome missing?

Conversations with my colleagues tell me that a lot of A&P faculty haven't given much thought to teaching their students about the human microbiome. 

In the A&P textbooks and curriculum documents we examined, microbiome coverage was often limited, scattered, or absent. That absence can easily be interpreted as a signal that the topic belongs somewhere other than the undergraduate A&P course. That makes perfect sense, right?

Other courses?

Some of our students may encounter the human microbiome in introductory biology, microbiology, pathophysiology, nutrition, or another course. That’s great. Important concepts should not appear once and then disappear.

We already revisit basic concepts from chemistry, cell biology, genetics, homeostasis, and other foundational areas in several courses. Each encounter lets students add new connections and consider the concept in a different context. Over time, those connections can become stronger and more complex, making the knowledge easier to retrieve and apply.

The A&P course brings its own perspective to the microbiome. Our task is to help students connect microbial communities with body structures, physiological functions, homeostatic mechanisms, health, and disease. Another biology course may approach the same concept from a different direction—and that is exactly as it should be. The courses complement one another rather than compete for ownership of the concept.

Big-picture thinking

The microbiome is also a wonderfully integrative A&P concept. Its connections across body systems help students develop the big-picture, whole-body thinking we want them to build.

That fits naturally with a long-standing theme of our textbook. Every chapter ends with a Big Picture section that asks students to step back from the details and see how structures and functions connect across the whole body. The microbiome practically demands that kind of thinking.

The microbiome also has known—and still-emerging—clinical applications that many of our health professions students are likely to encounter. Giving students a basic framework now helps prepare them to understand and apply those connections when they encounter them later in their education and careers.

Adding the microbiome doesn't have to mean adding much

We know that A&P evolves, and when there's something new that has proven its importance to our understanding of A&P, somebody has to take a step in that direction. 

Adding the human microbiome to A&P does not mean carving out a week of lectures or piling another large block of content onto an already crowded course. Our textbook's coverage is more substantial than it was in earlier editions—and more substantial than what we found in the other A&P textbooks we examined—but it is still concise.

Brief mentions throughout the book help students connect the microbiome with the structures and functions they are already studying. For many courses, assigning the short Chapter 49 as reading, rather than devoting an entire lecture to it, may be entirely sufficient.

The goal is not to turn A&P into a microbiology course. It is to give students enough of a framework to understand that microbial communities are part of the human biological story. Later—or earlier—encounters in introductory biology, microbiology, pathophysiology, nutrition, and other courses can add new layers. And as the clinical importance of the microbiome continues to develop, that framework gives students something sturdy on which to build.

Our textbook has been nudging instructors toward the microbiome with small steps starting in the early 1990s, culminating in the big step I've been describing here—a whole new microbiome chapter. You can wait if you want to, but I think my students are better prepared knowing the basics of the microbiome than if I'd never mentioned it in my course. They'll be applying it in their later courses and clinical settings, and I want to get my students ready by giving them a small, easy-to-grasp introduction in their A&P course. Maybe you already do that, too.

We don’t have to teach students everything currently known about the human microbiome. We do need to give them enough of the story to recognize its connections with human structure and function—and enough of a framework to keep learning as they encounter the microbiome again.

That’s why we believe the human microbiome belongs in A&P.

Doesn't hurt to take a look!

I strongly suggest that you take a look at the new Chapter 49: Human Microbiome.

If you haven't already requested a free instructor review copy of the new edition, click here and do that now. Then you'll receive it as soon as it becomes available on September 1, 2026