Muscle Anatomy and Physiology

Vocabulary flashcards covering key terms from the lecture on muscle anatomy and physiology.

Skeletal Muscle

Striated, voluntary muscle tissue attached to bones (or facial skin) that enables body movement.

Smooth Muscle

Non-striated, involuntary muscle located in the walls of hollow organs and blood vessels.

Cardiac Muscle

Involuntary, striated muscle found only in the heart; cells connect via intercalated discs.

Fascicle

A bundle of skeletal muscle fibers surrounded by connective tissue called the perimysium.

Perimysium

Connective tissue sheath that encloses each fascicle within a skeletal muscle.

Endomysium

Delicate connective tissue layer that wraps each individual skeletal muscle fiber.

Myofibril

Contractile organelle within muscle fibers composed of repeating units of actin and myosin.

Myofilament

Protein filament (thick myosin or thin actin) that forms part of a myofibril.

Actin

Thin filament protein that interacts with myosin during muscle contraction.

Myosin

Thick filament motor protein whose heads bind to actin to generate force.

Sarcomere

Smallest functional contractile unit of striated muscle, defined by Z-lines.

Sliding Filament Theory

Model stating that muscle contraction occurs as actin and myosin filaments slide past each other, shortening sarcomeres.

Neuromuscular Junction (NMJ)

Synapse where a motor neuron communicates with a muscle fiber to trigger contraction.

Action Potential

Rapid, transient change in membrane voltage that propagates along cells, initiating muscle contraction.

Intercalated Disc

Specialized junction connecting cardiac muscle cells, allowing synchronized contraction.

Pacemaker (Cardiac)

Intrinsic group of heart cells that spontaneously generate action potentials to set heart rhythm.