| A | B |
|---|
| skeletal system | the body's network of bones which form a rigid frame to support the body, protect internal organs, generate red blood cells, and store calcium and phosphorus |
| periosteum | a tough, tight-fitting membrane that covers the surface of bones |
| marrow | a red or yellow fatty tissue in certain bones that produces red and white blood cells |
| cartilage | a thick, tough, smooth, flexible tissue that is harder than flesh but softer than bone; it covers the ends of bones to allow movement and cushion shock |
| joint | any place where two or more bones meet; may be movable or immovable |
| ligament | a tough band of tissue that holds bones together at joints |
| immovable joint | a juncture of two or more bones, made so that little or no movement occurs |
| movable joinq | a place where two or more bones meet or are attached and allow a wide range of movement |
| fracture | a break in a bone |
| biomaterial | an artificial material that can be used to repair or replace body parts |
| osteoporosis | a disease that breaks down bone, making it brittle and weak |
| muscle | an organ that can relax and contract to allow movement |
| voluntary muscle | a muscle you can control, such as arm and leg muscles |
| involuntary muscle | a muscle that can't be consciously controlled, such as heart and digestive muscle |
| skeletal muscle | voluntary muscles that work in pairs to move bones |
| tendon | a thick band of tissue that attaches a muscle to a bone |
| smooth muscle | involuntary muscles that move many internal organs, such as the stomach, intestines, and blood vessels |
| cardiac muscles | involuntary muscle tissue found in the heart |
| epidermis | the surface or outer layer of skin |
| dermis | the inner layer of skin, it contains many blood vessels, nerves, and sweat glands |
| melanin | a pigment produced by the epidermis that gives skin its color |
