| A | B |
|---|
| axial skeleton | the 80 bones of the skull, spine, ribs, vertebrae, and sternum, or breastbone |
| appendicular skeleton | the 126 bones of the upper and lower limbs, shoulders, and hips |
| cartilage | a strong, flexible connective tissue |
| ossification | the process by which bone is formed, renewed, and repaired |
| ligament | a band of fibrous, slightly elastic connective tissue that attaches bone to bone |
| tendon | a fibrous cord that attaches muscle to the bone |
| osteoporosis | a condition in which there is the progressive loss of bone tissue |
| scoliosis | a lateral, or side-to-side, curvature of the spine |
| repetitive motion injury | damage to tissues caused by prolonged, repeated movements |
| smooth muscles | muscles that act on the lining of passageways and internal organs |
| skeletal muscles | muscles that are attached to bone and cause body movements |
| flexor | the muscle that closes a joint |
| extensor | the muscle that opens a joint |
| cardiac muscle | a type of striated muscle that forms the wall of the heart |
| muscle tone | the natural tension in the fibers of a muscle |
| tendonitis | the inflammation of a tendon |
| hernia | when an organ or tissue protrudes through an area of weak muscle |
| neurons | nerve cells |
| cerebrum | the largest and most complex part of the brain |
| cerebellum | the second largest part of the brain |
| brain stem | a three-inch-long stalk of nerve cells and fibers that connects the spinal cord to the rest of the brain |
| reflex | a spontaneous response of the body to a stimulus |
| epilepsy | a disorder of the nervous system that is characterized by recurrent seizures—sudden episodes of uncontrolled electrical activity in the brain |
| cerebral palsy | a group of nonprogressive neurological disorders that are the result of damage to the brain before, during, or just after birth or in early childhood |
