Homeostasis is the ability to maintain constant internal conditions when outside conditions change.
For example, when temperatures in the body fall below 37° C, the nervous system signals the muscular system to
cause the body to shiver. When you shiver, your muscles move. Tiny muscles attached to hairs on the skin contract and pull the hairs up straight, forming goose bumps. This movement generates thermal energy and helps raise body
temperature. Keeping the body’s temperature constant requires that the endocrine system, the nervous system, and the muscular system work together.
