Ch. 7.5 Muscular System key Terms
Abduction
Movement of a limb away from the midline of the body (e.g., lifting your arm out to the side).
Adduction
Movement of a limb toward the midline of the body (e.g., bringing your arm back to your side).
Cardiac Muscle
The specialized, involuntary muscle tissue found only in the heart. It is striated (striped) and contracts continuously to pump blood.
Circumduction:
A circular movement of a limb, creating a cone shape. It's a combination of flexion, extension, abduction, and adduction (e.g., circling your arm).
Contractibility
The ability of a muscle to shorten or thicken when it receives a stimulus.
Contracture
An abnormal, permanent shortening (contraction) of a muscle, tendon, or fascia, often leading to joint deformity and rigidity.
Dorsiflexion:
Bending the foot upward at the ankle, moving the toes toward the shin.
Elasticity:
The muscle's ability to return to its original length and shape after contracting or stretching.
excitability
The ability of a muscle to receive and respond to a stimulus, such as a nerve impulse.
Extensibility:
The ability of a muscle to be stretched or extended.
Extension:
Straightening a joint, which increases the angle between the bones (e.g., straightening your elbow).
Fascia
A band or sheet of connective tissue, primarily collagen, that attaches, stabilizes, encloses, and separates muscles and other internal organs.
Flexion
Bending a joint, which decreases the angle between the bones (e.g., bending your elbow).
Insertion
The point where a muscle attaches to the movable bone during a contraction.
Involuntary
Refers to muscle actions that are not under conscious control, such as the beating of the heart or digestion.
Muscle Tone
The state of partial, continuous contraction in a muscle, which is essential for posture and readiness to act.
Muscular System
The body system composed of skeletal, smooth, and cardiac muscles. It permits movement of the body, maintains posture, and circulates blood.
Origin
The point where a muscle attaches to the immovable or less movable bone.
Plantar Flexion
Bending the foot downward at the ankle, pointing the toes away from the shin (e.g., pressing a gas pedal).
Pronation
Turning the forearm so the palm faces downward (or turning the sole of the foot inward).
Rotation
Turning a bone around its own long axis (e.g., shaking your head "no").
Skeletal Muscle
Muscle tissue that is attached to bones by tendons. It is voluntary (consciously controlled) and striated, responsible for body movement.
Supination
Turning the forearm so the palm faces upward (or turning the sole of the foot outward).
Tendons
Tough, flexible bands of fibrous connective tissue that connect muscle to bone.
Visceral Muscle
Involuntary, non-striated muscle found in the walls of internal organs (viscera) like the stomach, intestines, and blood vessels.