So we have the thin filament and the thick filament that are also found in the cardiac and skeletal muscle. And we have a new type of filament known as the intermediate filament that is not found in skeletal and cardiac muscle. Now, thin filament is composed of actin, the protein actin, while thick filament is composed of the protein myosin. Now, the intermediate filament is composed predominantly of two types of proteins. We have Desmond as well as a protein known as vimentin. Now, we also have these regions we call the dense bodies, which are shown with these brown dots.