| A | B |
|---|
| connective tissue | keeps organs from falling apart |
| muscle tissue | made of cells that contract and relax |
| nervous tissue | sends electrical signals through body |
| hinge joint | lets your elbow bend in only one direction |
| ball and socket joint | allows free movement in all directions |
| skeletal muscle | has both voluntary and involuntary action |
| resistance exercise | muscles work against weight |
| aerobic exercise | muscles work steadily for a long period of time |
| sweat glands | helps keep body temperature from getting to high |
| keratin | a protein that makes skin tough |
| melanin | protects skin from cancer |
| valves | keep blood from flowing in the wrong direction |
| systemic circulation | blood movement through body |
| pulmonary circulation | blood movement between heart and lungs |
| heart attack | causes cell death in heart |
| heart failure | causes organ malfunction |
| vein | carries blood to heart |
| integumentary system | organ system that protects outside of body |
| epidermis | a surface layer of cells |
| joint | a place where two or more bones meet |
