Ch. 7.5 Muscular System Key terms
What is the muscular system?
The system composed of over 600 muscles that provides movement, posture, heat, and protection for the body.
What is excitability
The ability of a muscle to respond to a stimulus, such as a nerve impulse.
What is contractibility?
The ability of muscle fibers, when stimulated by nerves, to contract (become short and thick), which causes movement.
What is extensibility?
The ability of a muscle to be stretched.
What is elasticity?
The ability of a muscle to return to its original shape after it has contracted or stretched.
What is fascia?
A tough, sheetlike membrane that covers and protects muscle tissue.
What are tendons?
Strong, tough, fibrous connective-tissue cords that attach muscles to bones.
What is an origin?
The end of a muscle that attaches to a bone and does not move when the muscle contracts.
What is an insertion?
The end of a muscle that moves when the muscle contracts.
What is muscle tone?
The state of partial contraction in muscles, even when they are not in use.
What is a contracture?
A severe tightening of a flexor muscle, resulting in the bending of a joint.
What is cardiac muscle?
Muscle found in the walls of the heart; it contracts to circulate blood. It is an involuntary muscle.
What is visceral (or smooth) muscle?
Muscle found in the internal organs of the body, such as the digestive system, respiratory system, blood vessels, and eyes. It is an involuntary muscle.
What is skeletal muscle?
Muscle that is attached to bones and is responsible for body movement. It is a voluntary muscle.
What does involuntary mean?
Refers to muscles (like cardiac and visceral) that function without conscious thought or control.
What does voluntary mean?
Refers to muscles (like skeletal) that a person can control the action of.
What is abduction?
Moving a body part away from the midline of the body.
What is adduction?
Moving a body part toward the midline of the body.
What is flexion?
Decreasing the angle between two bones, or bending a body part.
What is extension?
Increasing the angle between two bones, or straightening a body part.
What is rotation?
Turning a body part around its own axis (e.g., turning the head from side to side).
What is circumduction?
Moving one end of a body part in a circle while the other end remains stationary (e.g., swinging an arm in a circle).
What is pronation?
Turning a body part downward (e.g., turning the palm of the hand down).
What is supination?
Turning a body part upward (e.g., turning the palm of the hand up).
What is dorsiflexion?
Bending the foot toward the knee.