Homeostasis

Homeostasis is the tendency of animals, including humans, to maintain relatively consistent internal environments by controlling temperature, metabolism, blood sugar, and other important states.

What is Homeostasis?

In a given day, people’s bodies change in myriad ways, and many people face vastly different environments. Your cold office and hot car both challenge your body, and the process of cooling down and slowing your heart rate after exercise is an important key to physical health. While it is impossible to maintain completely consistent internal conditions at all times, the human body is remarkably adept at keeping internal conditions relatively stable.

How Does Homeostasis Work?

Homeostasis works through two primary mechanisms:

• Positive feedback occurs when the body continually amplifies a bodily state, such as when oxytocin helps to amplify contractions during labor.
• Negative feedback works by keeping the body around a relatively steady “set point,” and is often compared to a thermostat. For example, when your body temperature increases, you’ll begin sweating to cool your body down, and as your body temperature cools, sweating will stop; if sweating were controlled by positive feedback, it would continue long after your body temperature returned to normal.

Examples of mechanisms that maintain homeostasis include sweating and increasing the heart rate to pump blood to the organs and muscles during exercise.

Problems With Homeostasis

Although the body is remarkably adept at maintaining homeostasis, some medical and environmental conditions can interfere with the process. For example, a person who is dehydrated will not be able to properly regulate her body temperature. Nutritional imbalances, hormonal disorders, infections, cancer, and a host of other ailments can also undermine homeostasis. When the body is unable to maintain consistent internal conditions, people can rapidly become weak or ill.

Reference:

1. Audesirk, T., Audesirk, G., & Byers, B. E. (2008). Biology: Life on earth with physiology. Upper Saddle River, NJ: Pearson Prentice Hall.

Last Updated: 08-7-2015