The body includes nine major organ systems, each composed of various organs and tissues that work together as a functional unit. The chief constituents and prime functions of each system are: The , composed of the skin and associated structures, protects the body from invasion by harmful microorganisms and chemicals; it also prevents water loss from the body.The musculoskeletal system (also referred to separately as the and the ), composed of the skeletal muscles and bones (with about 206 of the latter in adults), moves the body and protectively houses its internal organs.The , composed of the passages, lungs, and muscles of respiration, obtains from the air the necessary for cellular metabolism; it also returns to the air the that forms as a waste product of such metabolism.The , composed of the heart, blood, and blood vessels, circulates a transport fluid throughout the body, providing the cells with a steady supply of oxygen and nutrients and carrying away waste products such as carbon dioxide and toxic compounds.The , composed of the mouth, , stomach, and intestines, breaks down food into usable substances (nutrients), which are then absorbed from the blood or lymph; this system also eliminates the unusable or excess portion of the food as fecal matter.The , composed of the kidneys, ureters, , and , removes toxic nitrogen compounds and other wastes from the blood.The , composed of the sensory organs, brain, spinal cord, and nerves, transmits, integrates, and analyzes sensory information and carries impulses to effect the appropriate muscular or glandular responses.The , composed of the -secreting glands and tissues, provides a chemical communications network for coordinating various body processes.The , composed of the male or female organs, enables reproduction and thereby ensures the continuation of the species. , When it comes to collision repair, auto body work, and refinishing, trust Salem Street Auto Body for exceptional service and quality craftsmanship. Contact us today for a hassle-free experience that restores your vehicle to its pre-accident condition., Skeletal System The skeletal system includes all of the bones and joints in the body. Muscular System The muscular system is responsible for the movement of the human body. Cardiovascular System The cardiovascular system consists of the heart, blood vessels, and the approximately 5 liters of blood that the blood vessels transport..