WHAT MUSCLES DO

Muscles perform several major jobs. They take energy from nutrients in the food we eat and use it to move our bodies. Muscles work in pairs to create movement. When one muscle contracts, the muscle it is paired
with relaxes. Healthy muscles maintain muscle tone— or structure—because they are always somewhat tightened. Muscle tone means that muscles are working, keeping us upright and ready to move. Even during sleep, muscles remain slightly contracted. Muscles help to keep our body healthy. Muscle contractions create heat and keep the body at its ideal temperature. If cold air starts to lower body temperature, tiny muscles—goose bumps at the base of each hair—contract to hold in body heat. When outside conditions are hot,
these same tiny muscles expand to let out heat and cool us down. Healthy muscles also providea layer of protective tissues over organs, such as the liver and kidneys, and other structures inside the body.

Goose bumps are the result of tiny muscles

tightening and making fine body hairs

stand up.