Ch. 7.5 Muscular System Key terms
Abduction
Moving a body part away from the midline.
Contracture
A severe tightening of a flexor muscle resulting in bending of a joint.
Fascia
A tough, sheetlike membrane that covers and protects the tissue (used as an attachment for some muscles).
Muscular system
More than 600 muscles make up this system.
Skeletal muscle
Is attached to bones and causes body movement.
Adduction
Moving a body part toward the midline.
Dorsiflexion
Bending backward or bending the foot toward the knee.
Flexion
Decreasing the angle between two bones, or bending a body part.
Origin
The end of a muscle attachment that does not move when the muscle contracts.
Supination
Turning a body part upward.
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.
Insertion
The end of a muscle 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 (used to attach some skeletal muscles to bones).
Circumduction
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.
Extensibility
The ability to be stretched.
Involuntary
Functions without conscious thought or control. (Applies to cardiac and visceral muscle).
Pronation
Turning a body part downward.
Visceral (smooth) muscle
Is found in the internal organs of the body, such as those of the digestive and respiratory systems, and the blood vessels and eyes.
Contractibility
Muscle fibers that are stimulated by nerves contract, or become short and thick, which causes movement.
Extension
Increasing the angle between two bones, or straightening a body part.
Muscle tone
The state of partial contraction muscles are in at all times, sometimes described as a state of readiness to act.
Rotation
Turning a body part around its own axis; for example, turning the head from side to side.
Voluntary
A person has control over its action. (Applies to skeletal muscle).