But it works involuntarily unlike the skeletal muscle. Cardiac and skeletal muscles are both striated and contain an orderly arrangement of myofibrils and can be found in the body of vertebrates. Skeletal Cardiac And Smooth Muscle Structure Human Anatomy And Physiology Muscle Anatomy Physiology Relatively there is a huge difference in the length of a cardiac muscle fibre and a skeletal muscle fibre. . Cardiac muscle like skeletal muscle is a type of striated muscle. Skeletal muscle is voluntary but cardiac muscle is involuntary. Skeletal muscles can contract rapidly but get tired easily. 1 Thick and thin filaments are organized into sarcomeres. The cross-bridge cycling that results in shortening of the muscle is the same as it is in skeletal muscle so we will not repeat. Whereas endothelial cells smooth muscle cells and fibroblasts showed strong immunoreactivity for NMHC II-A and NMHC II-B cardiac myocytes only showed reac