Key Terms Ch. 7:5 Muscular System
voluntary
a person has control over its action
fascia
a tough, sheetlike membrane that covers and protects the tissue
elasticity
allows the muscle to return to its original shape after it has contracted or stretched
skeletal muscle
attached to bones and causes body movement
contract
become short and thick
flexion
decreasing the angle between two bones, or bending a body part
cardiac muscle
forms the walls of the heart and contracts to circulate blood
visceral (smooth) muscle
found in the internal organs of the body, such as those of the digestive and respiratory systems, and the blood vessels and eyes
involuntary
function without conscious thought or control
extension
increasing the angle between two bones, or straightening a body part
excitability
irritability, the ability to respond to a stimulus such as a nerve impulse
muscular system
made up of more than 600 muscles
abduction
moving a body part away from the midline
adduction
moving a body part toward the midline
circumduction
moving in a circle at a joint
contractibility
muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement
contracture
severe tightening of a flexor muscle resulting in bending of a joint
muscle tone
state of partial contraction
tendons
strong,tough, fibrous connective-tissue cords
extensibility
the ability to be stretched
insertion
the end that moves when a muscle contracts
rotation
turning a body part around its own axis; for example, turning the head from side to side
origin
when a muscle attaches to a bone, the end that does not move