muscular
The muscular system consists of all the muscles of the body. Does the word muscle make you think of the bulging biceps of a weightlifter, like the man in Figure below ? Muscles such as biceps that move the body are easy to feel and see, but they arent the only muscles in the human body. Many muscles are deep within the body. They form the walls of internal organs such as the heart and stomach. You can flex your biceps like a body builder but you cannot control the muscles inside you. Its a good thing that they work on their own without any conscious effort your part, because movement of these muscles is essential for survival.