Homeostatis

 

Homeostasis is quite crucial for the survival of organisms. It is often seen as a resistance to changes in the external environment. Furthermore, homeostasis is a self-regulating process that regulates internal variables necessary to sustain life.

In other words, homeostasis is a mechanism that maintains a stable internal environment despite the changes present in the external environment.

The body maintains homeostasis by controlling a host of variables ranging from body temperature, blood pH, blood glucose levels to fluid balance, sodium, potassium and calcium ion concentrations.

An Example of Homeostasis in Action
Receptor	Cutaneous receptors of the skin.
Control centre	Brain.
Effector	Blood vessels and sweat glands in the skin.
The skin has receptors that detect changes in temperature. If the external temperature rises or drops below the equilibrium, the control centre sends signals to the blood vessels and sweat glands in our skin to react accordingly. If the temperature is too hot, the blood vessels dilate (vasodilation) and cause a drop in the body temperature. Moreover, sweat glands produce sweat to accompany vasodilation. If the external temperature is too cold, the blood vessels constrict (vasoconstriction) and enable the body to retain heat.