関連ワード:
what kind of muscle is the heart composed of what type of muscle is the heart composed of what kind of muscle is the heart made of what type of muscle is the heart made of what kind of muscle is the heart made up of what kind of muscle is the heart made out of what type of muscle is the heart primarily composed of what kind of muscle tissue is the heart made of what type of muscle tissue is the heart composed of 25 what type of muscle is the heart composed of
