Primary structures of the body that include the bones, bone marrow, cartilage, joints, ligaments, synovial membrane, synovial fluid, and the bursa; all of which support and shape the body, protect the internal organs, and form some of the blood cells and store minerals.

The various parts of the skeletal system provide essential elements for the body to survive.

• Bones provide the structures for the body, protect the internal organs, and store mineral calcium.
• Bone marrow forms some blood cells while yellow bone morrow stores fat.
• Cartilage creates a smooth surface for motions within the joints and also provides protection for the ends of the bones that are parts of the joints.
• The joints, or points of connections between two bones, function with the muscles to make a variety of movements possible.
• Ligaments are tough tissues that connect and allow for a range of motions of the joints between bones.
• The synovial membrane forms the lining of synovial joints and secretes synovial fluid.
• Synovial fluid is used to lubricate the joints so they can move smoothly and easily.
• The bursa is the small fluid-filled sac located between movable parts of the body especially at the joints.