Chap 12 Physiology

A collection of vocabulary flashcards covering key terms and concepts related to muscle physiology.

Skeletal Muscle

Type of muscle tissue that is striated and voluntary, responsible for body movement.

Cardiac Muscle

Striated muscle found only in the heart, involuntary in nature.

Smooth Muscle

Non-striated and involuntary muscle found in the walls of hollow organs and tubes.

Myofibrils

Contractile elements in muscle fibers composed of myofilaments.

Myosin

A thick filament protein essential for muscle contraction; forms cross-bridges with actin.

Actin

A thin filament protein that, along with myosin, facilitates muscle contraction.

Sarcomere

The functional unit of contraction in muscle fibers, located between two Z lines.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Tropomyosin

A regulatory protein that covers myosin binding sites on actin filaments.

Troponin

A regulatory protein that binds to tropomyosin and actin, involved in muscle contraction regulation.

Sliding Filament Theory

The theory that explains muscle contraction by the sliding of actin and myosin filaments over each other.

Calcium Ions (Ca2+)

Essential for muscle contraction; triggers the interaction between actin and myosin.

ATP (Adenosine Triphosphate)

Energy molecule required for muscle contraction and relaxation.

Tetanus

A sustained muscle contraction resulting from high-frequency stimulation.

Isotonic Contraction

A contraction in which muscle length changes while the load remains constant.

Isometric Contraction

A contraction in which muscle length does not change while exerting force against an immovable object.

Fatigue

A decline in muscle tension as a result of previous muscular activity.

Myocardium

Mass of cardiac muscle cells connected by gap junctions, functioning as a single unit.

Muscle Spindle

Stretch receptors located in muscle that sense muscle length and changes in length.

Golgi Tendon Organs

Sensory receptors located at the junctions between muscles and tendons that sense muscle tension.

Cross-Bridge Cycle

The process of cross-bridges forming, moving, and detaching that enables muscle contraction.

Excitation-Contraction Coupling

The physiological process by which an action potential leads to muscle contraction.