Chains of neurons stretch throughout the body and carry signals from the body to the brain and back again. When you use your senses, a special sense organ detects a signal from the environment and then sends that signal to the brain to be interpreted. The chemicals hook up to special receptors on the sense organ, and trigger a signal to be sent back to the brain. Your senses of taste , smell , and even pain work that way. We'll talk about that next week.
Some sense organs respond to mechanical forces.
You also have a sense called proprioception that tells you where your body is and what it's doing. Close your eyes then raise your hand in the air. That's because your sense of proprioception sends you that information. Some sense organs respond to changes in temperature . Now count up how many senses we've talked about.