Homeostasis refers to the ability of an organism or environment to maintain a state of internal balance and physical wellbeing in spite of changes or outside factors. Successful homeostasis is vital to the survival of any living thing, and being able to maintain homeostasis even in adverse conditions is one of the most important evolutionary advantages.
Examples of Homeostasis in the Human Body
The human body is an amazingly complex machine, but many of its parts and processes exist simply to maintain homeostasis. That is, the machine exists so the machine can continue to exist.
Humans' internal body temperature is a great example of homeostasis. When someone is healthy, their body maintains a temperature close to 98.6 degrees Fahrenheit (37 degrees Celsius). Being warm-blooded creatures, humans can increase or decrease temperature internally to keep it at a desirable level. Whether you're lying in the summer sun or playing in the winter snow, your body temperature only changes by a degree or two. That's an example of homeostasis being maintained. When you get shivery in the cold, or sweat in the summer, that's your body trying to maintain homeostasis.
Glucose is the most basic form of sugar, and the only type the body can use directly. The body must maintain proper glucose levels to ensure a person remains healthy. When glucose levels get too high, the pancreas releases a hormone known as insulin. If blood glucose levels drop too low, the liver converts glycogen in the blood to glucose again, raising the levels.
When bacteria or viruses that can make you ill get into your body, your lymphatic system kicks in to help maintain homeostasis. It works to fight the infection before it has the opportunity to make you sick, ensuring that you remain healthy.
The maintenance of healthy blood pressure is an example of homeostasis. The heart can sense changes in blood pressure, sending signals to the brain, which then sends appropriate instructions back to the heart. If blood pressure is too high, the heart should slow down; if it is too low, the heart should speed up.
More than half of a human's body weight percentage is water, and maintaining the correct balance of water is an example of homeostasis. Cells that have too much water bloat and can even blow up. Cells with too little water can end up shrinking. Your body (and a healthy intake of fluids) maintains a proper water balance so that neither of these situations occurs.
Calcium levels in the blood must be maintained at proper levels. The body regulates those levels in an example of homeostasis. When levels decrease, the parathyroid releases hormones. If calcium levels become too high, the thyroid helps out by fixing calcium in the bones and lowering blood calcium levels.
The nervous system helps keep homeostasis in breathing patterns. Because breathing is mostly involuntary, the nervous system ensures that the body is getting much needed oxygen through breathing the appropriate amount of oxygen.
Eating, drinking, even simple breathing can introduce indigestible and even dangerous substances into the body. The body maintains homeostasis by eliminating these substances through the urinary and digestive systems. An individual simply urinates and defecates the toxins and other nasty things from the blood, restoring homeostasis to the human body.
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