Biceps: Main function is at the bottom where it flexes the forearm at the elbow, necessary for movement of the elbow and lifting objects.
Abdominals: The abdomen is where most of the absorption and digestion of food occurs. Vital organs inside the abdomen include the liver, the kidneys, the pancreas and the spleen.
Triceps: Enables extension and retraction of the forearm. Triceps also serve to stabilize the shoulder joint at the top of the humerus. The shoulder has the greatest range of motion of any joint in the body, possessing the ability to turn and rotate in many directions.
Deltoid: The deltoid muscle is responsible for arm rotation and stopping dislocation and injury to the humerus when carrying heavy loads.
Calves: Primarily involved in running, jumping and other "fast" movements of the legs, and to a lesser degree, in walking and standing.
Pectorals: Across the chest from the shoulder to the breastbone. Aside from helping to move the arms, it also helps with deep breathing, they contract to move the rib cage which lets the lungs expand.
Quadriceps: The quadriceps are actually a group of muscles, one of the largest. It is made up of four muscles: the rectus femoris, vastus lateralis, vastus intermedius and vastus medialis. The muscles join above the knee cap and work with the quadriceps tendon and patellar tendon -- at the kneecap -- to straighten the knee. Each of the muscles that make up the quadricep have their own responsibility as well.
Ulnars: Lets the wrist flex and bend, and also allows it to bend sideways towards the forearm.
External Obliques: The external obliques on either side not only help rotate the entire torso, but they also help pull the entire chest downwards to compress the abdominal cavity. The external oblique muscles also support the rotation of the spine.
Tibias: The tibia is the largest muscle at the front of the leg. It helps the foot extend upward, flex the toes, and holds up the arch of the foot.
Heart: The heart sends blood around your body, the blood provides your body with oxygen and nutrients that it needs to survive, and also carries away waste. Without the heart doing its job, our body's normal functions would fail. Without the heart beating and performing properly, the body simply wouldn't be able to survive.