Maintaining one’s health starts with preventive care. However, in order to know what’s best for your body, it helps to have a knowledge of its inner workings. One curiosity in humans—and most animals—is the tendency to have duplicate organs: two lungs and two kidneys, for example. The guide below explores the reason for doubling up in some cases and not in others.

Understanding Single & Paired Organ Types  

What Is Bilateral Symmetry?

Most organisms have bilateral symmetry, which means their two sides are equally mirrored if you were to draw a line down their center. Birds, fish, most primates, and mammals follow this arrangement, while many invertebrates, like sponges, don’t. Thus, one theory behind bilateral symmetry is that this balanced composition better supports movement for creatures with a spinal system.

Yet, the question remains: why are some organs grown in pairs, while we only have one heart and brain? Evolutionary anthropologists suspect we have dual parts because we have a basic need for them. For instance, while we could see with one eye, having two gives us improved depth perception. Likewise, we have two lungs because they contain more surface area than one would have alone. This allows for the presence of more alveoli, or air sacs, which expand when you breathe in. 

Conversely, the single organs we have, including the heart, brain, and pancreas, function at full capacity on their own. Since most of these organs are located in the center of the body, they still adhere to the principle of bilateral symmetry.

What Happens When Someone Loses an Organ?

This being said, the human body is amazing at working with what it has. Should you lose a lung or kidney due to birth defects, surgical removal, or donation, most often, your remaining one will grow and adapt to accommodate your needs. 

While people with a solitary kidney must take some additional preventive care steps such as controlling blood pressure and preventing injury, many lead healthy, full lives. People born with a single kidney may experience a slight loss of function, but this usually takes at least 25 years to occur. Those who have lost a lung can also recover, although they will run out of breath more easily and should avoid sports and other high-energy activities as a precaution.

In addition to understanding the roles of your different organs, one of the pillars of a long, healthy life is receiving excellent preventive care. At Santiam Hospital in the Mid-Willamette Valley area of Oregon, providing superior patient care is the primary focus. While the hospital employs a broad range of surgeons and specialists, its satellite locations also provide preventive care to help you stay healthy at every age. See their full list of services online or call (503) 749-4734 to schedule an appointment.