What are muscles? Simply put, they are stretchy fibers. The human body has three types of muscles, cardiac muscles, smooth muscles, and skeletal muscles. Cardiac muscles line the heart and help it pump blood. Smooth muscles line the organs of the body, allowing the organs to perform their specific functions. Finally, there are skeletal muscles, the type of muscle that most people think of when they think about muscles. Skeletal muscles, also referred to as striated muscle, help up support our weight, walk, run, jump, lift objects, type on a keyboard, keep our joints stable and produce heat (thermogenesis). The body has over 600 skeletal muscles.
Unlike cardiac and smooth muscles, which perform their functions independently (involuntary), skeletal muscles are voluntary. That is, we control their actions. Some skeletal muscles contract quickly, using short bursts of energy. Some skeletal muscles move slowly, like the muscles that support our back, and posture.
In this course we will look at how skeletal muscle move through muscle contraction and their relationship to the bones, tendons, and ligaments. We will also review how muscles are named and become familiar vocabulary used to describe the location and actions of each muscle.