What are Biceps and triceps made of?

Biceps and triceps are both muscles. Muscles are made up of bundles of muscle fibres. Muscle fibres are made up of myofibrils. Myofibrils are made up of actin and myosin filaments. Actin and myosin filaments are made up of proteins. The proteins in actin and myosin filaments are called actin and myosin, respectively.