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 a bending of a joint
contracture
increasing the angle between two bones, or straightening a body part
extension
This state of partial contraction [at all times, even when not in use]
muscle tone
turning a body part around its own axis
rotation
moving a body part toward the midline
adduction
bending backward or bending the foot toward the knee
dorsiflexion
a tough, sheetlike membrane that covers and protects the tissue
fascia
More than 600 muscles make up the system known as the muscular 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
decreasing the angle between two bones, or bending a body part
flexion
The end [of a muscle] that does not move
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
circumduction
irritability, the ability to respond to a stimulus such as a 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 [that attach skeletal muscles to bones]
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
is found in the internal organs of the body, such as those of the digestive and respiratory systems, and the blood vessels and eyes
visceral (smooth) muscle