Structure Determines Function

Teaching Archive—Entry 003

Dr. Dean J. Scherer
Professor of Human Anatomy & Physiology

One of the most fundamental principles students encounter in the study of anatomy and physiology is the relationship between structure and function.

At first, anatomy and physiology may appear to be separate disciplines. Anatomy focuses on the physical structures of the body—bones, muscles, organs, and tissues—while physiology examines how those structures perform their roles within the living system. Yet in reality, these two perspectives are inseparable. The form of a biological structure is closely linked to what it does.

In other words, structure determines function.

Throughout my years of teaching anatomy and physiology, I have often summarized this idea for students in a simple phrase:

Form follows function.

The shape, organization, and physical characteristics of a biological structure reflect the job it must perform. When students begin to recognize this relationship, anatomy becomes far more than a list of names to memorize. Structures begin to reveal their purpose.

This principle can be seen throughout the human body. The shape of a bone reflects the forces it must support. The architecture of muscle fibers allows contraction and movement. The branching pattern of blood vessels enables efficient transport of oxygen and nutrients. Even at the microscopic level, the structure of cells and their internal components is closely aligned with the tasks they perform.

Consider the lungs. Their delicate, branching airways terminate in millions of tiny air sacs known as alveoli. Each alveolus possesses an extremely thin membrane and a large surface area, allowing oxygen and carbon dioxide to diffuse efficiently between air and blood. The structure of these tissues is not accidental; it is precisely suited to their function in gas exchange.

Similar relationships can be observed in nearly every system of the body. The long lever arms of bones enable movement through muscle contraction. The highly folded surface of the small intestine increases the area available for nutrient absorption. The specialized electrical properties of cardiac muscle allow the heart to beat in coordinated rhythms that sustain circulation.

When students begin to see anatomy through this lens, the subject changes in a profound way. Structures are no longer simply names attached to diagrams; they become solutions to functional challenges faced by the organism.

Understanding anatomy then becomes a process of discovery.

Instead of asking only “What is this structure called?” students begin asking a deeper question:

“Why is it built this way?”

That question often leads directly to the function the structure performs.

Over many years in the classroom, I have seen how this simple idea can reshape the way students approach the human body. When they recognize that form follows function, anatomy becomes more logical, more interconnected, and far easier to understand.

The principle that structure determines function therefore represents more than a statement about biology. It is a guide for how to study the body itself—by observing how form and purpose work together within the remarkable systems that sustain human life.