Homeostasis is the tendency of the body to maintain a relatively constant internal environment. A specific example of this that everyone knows is the typical temperature range of the human body is between 36.5-37.5°C. If that temperature raises 0.5°C and reaches 38°C, that person has a serious fever. If it raises 2 more degrees (40°C) they run a serious risk of suffering from heat stroke. If you lower that typical range to 35°C, the person instead begins to suffer from hypothermia.
This example illustrates the very serious medical implications when the body falls outside of this normal homeostatic temperature range, but that is only one factor that the body constantly maintains. Nutritional solutes (ex. sugar levels), waste solutes, pH, hormone levels, and pressure are constantly being balanced in the blood. Viruses, bacteria and other microbes can infect our body and our lymphatic system is constantly to fight against infections. Water levels in our cells, extracellular fluid, and blood needs to be constantly maintained. Even simple daily matters such as eating, drinking, breathing and going to the washroom are examples of your body maintaining homeostasis.
To maintain homeostasis, the human body uses the Nervous System and the Endocrine System, but first we need to understand the overview of the two types of mechanisms through which homeostasis is achieved.
Negative Feedback Mechanism
Negative Feedback: When the response compensates for the initial stimulus (ex. too hot -->respond by cooling down)
- By far the most common
- Regulates temperature, pH, glucose, Ca2+ concentration
Analogy: Comparing your body to your house thermostat:
