Ever wondered how your heart is able to pump continuously, or how you are able to lift up heavy things, or even digest food?  The answer is found in your muscles!  This article gives a basic description of the different types of muscles (smooth, cardiac, and skeletal), and the roles each type plays throughout your body.  There is also a short video and several figures displaying the different muscle types, and the brain’s role in coordinating muscle contraction and extension.  This is a great starting point for learning about an essential part of the human body.