This video lecture from Support and Movement (F.Sc. second year Biology) covers: Ultrastructure of skeletal muscles i.e. muscle bundles, muscle fibers, myofibrils and myofilaments. It also covers sliding filament model that describes how the muscles work. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.