What do muscle cells do?

It depends upon the type of muscle cells, but their basic function is to contract and relax to aid locomotion (changing positions) or movement (random reaction to a stimulus) in higher animals. Smooth muscle cells control involuntary functions such as blinking. Striated muscle cells control voluntary such as flexing one's arms. read more

The cells do not need to be as elongated as skeletal muscle fibers, because the motion created by these muscles is more gradual and requires less energy. Cardiac muscle tissue has striations like that of skeletal muscles, but the cells are smaller, like those of smooth muscles. read more

the function of a muscle cell is, by definition, to move. this can be accomplished when the cell contracts. contracting makes it denser, which is why when you feel a relaxed muscle in your arm suddenly tense up, it hardens. A muscle cell expands and contracts in order to allow the human body to control the movement of it's limbs. read more