Controls hormones and influences growth, sleep, and reproduction

Keeps you healthy by defending against illness and infections

Pumps blood and carries oxygen to different parts of the body

Breaks down food to allow the body to absorb the nutrients

Allows urine waste to exit the body

Defense from injury

Allows you to move your body when learning a new tik tok dance

Takes in oxygen and removes carbon dioxide with each breath you take (20,000 a day)

Protects vital organs and provides structures

Sends signals all over the body

The major veins surrounding the eye of the horned lizard are controlled by muscles. They shoot blood out of their eyes when predators approach.

Opossums play dead when they feel threatened. Their heart rate decreases, muscles stiffen, and urine is sometimes released.

Pistol shrimp have a front claw that acts like a water gun. Muscles contract and pull against the exoskeleton to close its claw. Water is displaced rapidly and shoots out at predators.