Ch. 7.5 Muscular System Key terms
moving a body part away from the midline
Abduction
a severe tightening of a flexor muscle resulting in bending of a joint
Contracture
increasing the angle between two bones, or straightening a body part
extension
the state of partial contraction, described as a state of readiness to act
muscle tone
turning a body part around its own axis; for example, turning the head from side to side
Rotation
moving a body part toward the midline
Adduction
bending backward or bending the foot toward the knee
Dorsiflexion
decreasing the angle between two bones, or bending a body part
flexion
more than 600 muscles make up this system
muscular system
is attached to bones and causes body movement
skeletal muscle
forms the walls of the heart and contracts to circulate blood
cardiac muscle
allows the muscle to return to its original shape after it has contracted or stretched
elasticity
a tough, sheetlike membrane that covers and protects the tissue, including the deep muscles of the trunk and back
fascia
The end that does not move when a muscle attaches to a bone
Origin
turning a body part upward
Supination
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
Circumduction
irritability, the ability to respond to a stimulus such as nerve impulse
Excitability
the end that moves when the muscle contracts
insertion
bending forward or bending the foot away from the knee
plantar flexion
strong, tough, fibrous connective-tissue cords
Tendons
muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement
Contractibility
the ability to be stretched
Extensibility
meaning they function without conscious thought or control
Involuntary
turning a body part downward
Pronation
also called smooth muscle, is found in the internal organs of the body, contracts to cause movement in those organs
visceral muscle