Articulations / Joints Supplementary Information

These flashcards cover key vocabulary terms and concepts related to muscle tissue structure, function, and disorders.

Skeletal Muscle Tissue

Striated and voluntary muscle tissue responsible for movement.

Cardiac Muscle Tissue

Striated and involuntary muscle tissue found in the heart.

Smooth Muscle Tissue

Visceral, nonstriated and involuntary muscle tissue found in hollow organs.

Excitability

The ability of a cell to receive and respond to a stimulus by changing its membrane potential.

Contractility

The ability of a muscle to shorten forcibly when adequately stimulated.

Extensibility

The ability of a muscle to extend or stretch.

Elasticity

The ability of a muscle cell to recoil and resume its resting length after stretching.

Epimysium

An overcoat of dense irregular connective tissue that surrounds the whole muscle.

Perimysium

Dense irregular connective tissue surrounding bundles of muscle fibers called fascicles.

Endomysium

A wispy sheath of fine areolar connective tissue that surrounds each individual muscle fiber.

Origin

The fixed or less movable attachment point of a muscle, usually closer to the body’s center.

Insertion

The movable attachment point of a muscle that moves toward the origin when the muscle contracts.

Z Disc

The structure where actin is bound within a sarcomere.

I Band

The region of a sarcomere that contains only thin filaments.

H Zone

The region of a sarcomere that contains only thick filaments.

M Line

The line in the middle of the sarcomere where thick filaments are linked by accessory proteins.

A Band

The region in a sarcomere that contains mostly thick filaments but also thin filaments at the edges.

Sliding Filament Theory

The theory that explains how muscles contract by the sliding of actin and myosin filaments past each other.

Neuromuscular Junction

The synapse or junction where the axon terminals of a motor neuron meet the muscle fiber.

Acetylcholine (ACh)

A neurotransmitter released at the neuromuscular junction that stimulates muscle contraction.

Action Potential

An electrical current generated in the sarcolemma that activates muscle contraction.

Excitation-Contraction Coupling

The process that links the action potential to muscle contraction.

Latent Period

The initial phase of muscle contraction where cross bridges begin to cycle but tension is not measurable.

Period of Contraction

The phase in muscle contraction where cross bridges are active and tension increases.

Period of Relaxation

The final phase of muscle contraction where muscle tension decreases to zero.

Isotonic Contraction

Muscle contraction that occurs when muscle tension overcomes the load, causing the muscle to shorten.

Isometric Contraction

Muscle contraction where muscle tension increases but the load is not moved.

Creatine Phosphate System

A mechanism for ATP regeneration in muscles using creatine phosphate to quickly produce ATP.

Anaerobic Glycolysis

The process of ATP production that occurs when glucose is broken down without oxygen.

Aerobic Cellular Respiration

The process of ATP production that occurs in the presence of oxygen, providing the majority of ATP for sustained activity.

Muscle Atrophy

Degeneration and loss of muscle mass due to disuse, disease, or aging.

Myasthenia Gravis

An autoimmune disease that causes generalized muscle weakness by destroying ACh receptors.

Rigor Mortis

The stiffening of muscles after death due to cross-bridge detachment requiring ATP.

Tetanus

A bacterial disease causing painful skeletal muscle spasms and potentially fatal respiratory failure.

Muscular Dystrophy

A group of inherited diseases causing muscle fiber degeneration.