SciTech

Homeostasis balances conditions

Credit: Kathy Lee/Staff Credit: Kathy Lee/Staff

The basis of any organism, from the small bacteria that live in volcanoes to the higher-functioning entities that we humans are, is the principle of homeostasis. The Discovery Health website defines homeostasis as “a state of balance within the body.” In other words, homeostasis is the act of maintaining the internal environment of an organism’s body to achieve optimal function. But why is this state important at all for the functioning of the organism, and how exactly does it work?

The answer to the first question is simple. We do so many things each day, and each function is carried out by a specific organ as it collaborates with the other parts of the body that need a very specific environment to function correctly. Homeostasis maintains these different environments so that each organ can function at maximum potential. For example, the human body maintains an average temperature of 98.6˚F; according to Gizmodo, this is warm enough to prevent fungal infection, but cold enough that our bodies don’t maintain a metabolism that requires constant consumption of food.

Even the slightest change in our internal environments can lead to significant impact on our bodies. Body temperature is tightly regulated and has good reason to be. According to the website Biology Reference, “If core body temperature goes below 33˚C (91˚F), a person is likely to die of hypothermia, and if it goes above 42˚C (108˚F), death from hyperthermia is likely.” With such consequences, it makes sense that homeostasis is an important tool in our bodies.

Homeostasis is a complex process, with every system working in sync to ensure that the environment is “just right” for their function. But mostly, homeostasis is controlled by negative and positive feedback loops.

Negative feedback loops generally involve receptors which detect deviations from normality; a control center, such as the brain, which integrates all of the information fed to it by the receptors; and effectors which receive messages from the control center and induce a change to correct the initial deviation. An example of this can be found in the body’s regulation of blood pressure. When receptors in blood vessels detect an abnormal amount of resistance of blood flow against the vessel walls, they send a message to the brain, which in turn commands the heart to lower its blood flow rate and the blood vessels to increase in diameter, lowering blood pressure.

The body also uses positive feedback loops to maintain homeostasis. In this method, an abnormality in the body that disturbs homeostasis triggers a cascade of events that then results in the abnormality disappearing and causing homeostasis to be returned. A good example of this can be seen in blood clotting. When one is wounded, the blood vessels in the area break, causing the blood in them to flow out rapidly. Thrombin, a protein that aids in blood clotting, rushes in and initiates the production of more thrombin to speed up the clotting process. While negative feedback loops slow down a process such as heart rate in response to high blood pressure, these positive feedback loops correct an abnormality by speeding up a process like the production of blood clotting proteins.

Positive and negative feedback are just two methods our bodies are known to use to keep the intricate balance of homeostasis. A stable internal environment is highly important for our bodies’ functions. As such, homeostasis is a key component of of life function and is what enables us to do the multitude of activities we participate in daily.