Most people would say you have five senses: touch, sight, hearing, smell and taste. Recently, scientists have expanded their view of what makes up a sense.

For example, some would argue that hunger is a sense and that the abilities to feel pain and pressure are senses.

Without your sense of balance, you couldn't stand or walk without falling on your face. Balance is the result of the brain processing information that comes from three systems: your eyes, your inner ear and something called proprioception.

You obviously need your eyes to see. For example, you couldn't read this article or build a Lego set without good vision. But your eyes also let you know where you are relative to your surroundings. Is the tree in front of you close up, or is it farther away? At any point in time, are you moving forward, moving sideways or standing still? Knowing where you are relative to your environment is essential for good balance.

Your inner ear contains the vestibular system, which has three semicircular canals. Those canals are filled with a liquid called endolymph. When you move your head up and down or rotate it side to side, the endolymph moves and triggers hair cells within the semicircular canals to send nerve signals to the brain. The brain interprets these signals to stabilize eye movement and your sense of where you are relative to your surroundings.

Proprioception refers to the ability to know where your body parts are in relation to one another. For example, you could bend over and scratch your foot without looking. You could also drink a glass of water with your eyes closed. Stretch receptors in your skin, muscles and joints relay positional information to your central nervous system. Many regions in the brain are involved with understanding these signals.

Every second that you stand or move around, thousands of nerve signals pass back and forth between your body parts and brain. This exchange of information allows your brain to know where you are in space and to coordinate the muscular contractions needed to carry out specific actions and to keep you from falling. Of course, we all stumble from time to time, which shows that the system isn't perfect.

If you experience dizziness or a head injury, your doctor can check your balance by asking you to do the following tasks:

- Hold your arms away from your body and alternate bringing each index finger to the tip of your nose while your eyes are closed.

- Stand with your feet together and your eyes closed.

- Walk heel to toe like a tightrope walker. Do it with your arms at your side and then with your arms across your chest.

If you want to check your balance, you can easily do these tests at home. Just make sure your mom or dad is watching so you don't hurt yourself. You can even attempt something a little harder. Try to stand on one foot without falling for 30 seconds. Now, try it again with your eyes closed. It's much harder without your eyes, isn't it?