Ch. 7.5 Muscular System Key terms
abduction
moving a body part away from the midline.
adduction
moving a body part toward the midline.
cardiac muscle
forms the walls of the heart and contracts to circulate blood.
circumduction
moving in a circle at a joint.
contradictability
muscle fibers... contract, or become short and thick, which causes movement.
contracture
a severe tightening of a flexor muscle resulting in bending of a joint.
dorsiflexion
bending backward or bending the foot toward the knee.
elasticity
allows the muscle to return to its original shape after it has contracted or stretched.
excitability
irritability, the ability to respond to a stimulus such as a nerve impulse
extensibility
the ability to be stretched.
extension
increasing the angle between two bones, or straightening a body part.
fascia
a tough, sheetlike membrane that covers and protects the tissue.
flexion
decreasing the angle between two bones, or bending a body part.
insertion
The end that moves when the muscle contracts.
involuntary
function without thought or control
muscle tone
partially contracted at all times, even when not in use.
muscular system
the system... [made up of] more than 600 muscles.
origin
the end that does not move
plantar flexion
bending forward or bending the foot away from the knee.
pronation
turning a body part downward.
rotation
turning a body part around its own axis.
skeletal muscle
attached to bones and causes body movement.
supination
turning a body part upward.
tendons
strong, tough, fibrous connective-tissue cords.
voluntary
when a person has control over the action of the muscle