How does an arm work?

Movement in your arm is controlled by muscles. Muscles in the arm work in pairs where one will pull the arm up (Biceps) and one pull the arm down (Triceps). To pull the arm up the muscle tightens in a process known as contraction.
arm muscles
Muscle is made up of bundles of muscle cells. The cells in the muscle all contract together to enable movement, contraction is possible due to two factors in cells known as actin and myosin. Actin and myosin slide over each other in a controlled manner to induce contraction.
myosin actin
But how do all the muscle cells in the arm know to contract at the same time? This is controlled by nerves which enable signals to be passed from the brain to the muscles. The area in the brain that controls movement is known as the motor cortex. When the brain wants a muscle to move, it signals via nerves to the muscle to all contract (or relax) at the same time.

Understanding how our body controls movement can help in the development of new prosthetics.

Watch a video showing the anatomy scanner created for our exhibition: