Key terms
abduction
Moving a body part away from the midline
contracture
A severe tightening of a flexor muscle resulting in bending of a joint.
extension
increasing the angle between two bones, or straightening a body part.
muscle tone
Sometimes described as a state of readiness to act
rotation
Turning a body part around its own axis, for example, turning the head from side to side.
adduction
moving a body part toward the midline
dorsiflexion
bending backward or bending the foot.
fascia
A tough, sheetlike membrane that covers and protects the tissue
muscular system
More than 600 muscles make up this system
skeletal muscle
Is attached to bones and causes body movement
cardiac muscle
Forms the walls of the heart and contracts to circulate blood
elasticity
allows the muscle to return to its original shape after it has contracted or stretched
flexion
decreasing the angle between two bones, or bending a body part
origin
When a muscle attaches to a bone, the end that does not move
supination
turning a body part upward
circumduction
Moving in a circle at a joint, or moving one end of a body part in a circle while the other end remains stationary, such as swinging an arm in a circle.
excitability
irritability, the ability to respond to a stimulus such as nerve impulse.
insertion
The end that moves when the muscle contracts
plantar flexion
bending forward or bending the foot toward the knee
tendons
Strong, tough, fibrous connective tissue cords
contractibility
muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement.
extensibility
the ability to be stretched
involuntary
Cardiac muscle and visceral muscle cannot function without conscious thought ot control.
pronation
turning a body part downward
visceral muscle
Found in the internal organs of the body, such as those of the digestive and respiratory systems, and the blood vessels and eyes