There are 10 organ systems that work together in the human body: circulatory, respiratory, skeletal, muscular, digestive, excretory, reproductive, integumentary, nervous, and endocrine. These systems are composed of tissues and organs working interdependently. The circulatory system transports blood throughout the body while taking oxygen from the respiratory system. The skeletal system includes bones and provides structure, movement, and protection to the body. Muscles work with bones to enable movement and are either voluntary or involuntary.