How do we regulate the body?

-Karthik Gurumurthy

An animal must keep the environment inside its body comfortable for its cells and organs, no matter how the environment outside its body changes. Cells can do their jobs only if their conditions stay fairly constant. If the inside environment gets too hot or too cold, or too wet or too dry, the cells can’t work properly. They also need a continuous supply of nutrients, water, and oxygen, the right amount of salt, and a way to get rid of wastes. The ability of animals to do these things – to do these things- to regulate the internal environment of their bodies- is called homeostasis.

The body has ways of telling an animal what it needs. For example, if the inside of an animal is dehydrated (too dry), the animal will become thirsty and drink. Likewise, if the body needs more nutrients, the animal will become hungry and look for something to eat.

Usually, your body maintains homeostasis without your having to think about it. Think about your body temperature.  If you are cold, you automatically start to shiver – a shaking muscle movement that speeds the flow of blood and warms you up. If you are hot, you naturally sweat. That is, your skin produces moisture that cools you down was it evaporates.

Sweating and shivering are called physiological actions- they occur inside the body. But if you can’t get warm enough by shivering, you might put on a sweater.

If you can’t cool down enough by sweating, you might turn on a fan or air conditioner. These are behavioral actions. They also help maintain homeostasis.