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 the bending of a joint.
Extension
Increasing the angle between two bones, or straightening a body part.
Muscle tone
A state of partial contraction in muscles at all times.
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 fibrous membrane that covers, supports, and protects the tissue.
Muscular system
The system made up of more than 600 muscles.
Skeletal muscle
Muscle tissue attached to bones that causes body movement. It is voluntary and striated.
Cardiac muscle
Muscle tissue found only in the walls of the heart. It is involuntary and striated with indistinct striations.
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
The end of the muscle that does not move when the muscle contracts; it is attached to the part that is less movable.
Supination
Turning a body part upward.
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.
Excitability
The ability to respond to a stimulus such as a nerve impulse.
Insertion
The end of the muscle that moves when the muscle contracts; it is attached to the part that moves.
Plantar flexion
Bending forward or bending the foot away from the knee.
Tendons
Tough, fibrous connective tissue cords that attach muscles to bones.
Contractibility
The ability of muscle fibers to be stimulated by nerves, contract, or become short and thick, which causes movement.
Extensibility
The ability to be stretched.
Involuntary
Muscle action that functions without conscious thought or control (e.g., cardiac and visceral muscle).
Pronation
Turning a body part downward.
Visceral muscle
Muscle tissue found in the internal organs of the body, such as the digestive and respiratory systems. It is involuntary.