Ch. 7.5 Muscular System
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
Muscles are partially contracted at all times, even when not in use.
rotation
turning a body part around its own axis;
adduction
moving a body part toward the midline
dorsiflexion
bending backward or bending the foot toward the knee
fascia
a tough, sheetlike membrane that covers and protects the tissue.
muscular system
More than 600 muscles make up the system
skeletal muscle
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
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
excitability
irritability, the ability to respond to a stimulus such as a nerve impulse
insertion
The end that moves when the muscle contracts
plantar flexion
bending forward or bending the foot away from the knee
tendons
strong, tough, fibrous, connective-tissue cords
contractibility
muscle fibers that are stimulated by nerves contract, or become short and thick
extensibility
the ability to be stretched
involuntary
they function without conscious thought or control.
pronation
turning a body part downward Supination: turning a body part upward
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