The Nervous system's main parts are the brain and the spinal cord.

The brain sends a signal to parts of the body.

It tells the other systems what to do.

The most important part of the digestive system is the body.

The system separates the good food from the bad food.

The bottom of your tongue produces saliva that breaks down food so the food does not get in your digestive system.

The most important part of the Respiratory system is the lungs

The lungs help you breathe air, we breathe air through our lungs nose and mouth.

The Respiratory gives the rest of your body air.

The most important part of the Muscular System is your muscles.

The Muscular system gives you strength and agility

It helps your body even more stronger and makes you go faster.

The most important part of the skeletal system is the skeleton.

Our bones make a lot of things possible.

Our bones help our muscles because without our bones muscles would be pointless.

The most important part of the circulatory system is the heart

The heart pumps out blood and gives that blood to the rest of our body

The heart connects to a lot of parts of the body, without it we would be dead.