Nightmare of Poodle Dog

Skeletal Muscle

Voluntary, striated muscle tissue attached to bones and responsible for body movement.

Cardiac Muscle

Involuntary, striated muscle tissue found only in the heart with intercalated discs.

Smooth Muscle

Involuntary, non-striated muscle tissue found in the walls of hollow organs.

Endomysium

Connective tissue that surrounds individual muscle fibers.

Perimysium

Connective tissue that surrounds bundles of muscle fibers called fascicles.

Epimysium

Connective tissue that surrounds the entire skeletal muscle.

Tendon

Dense regular connective tissue attaching muscle to bone.

Myofibril

Long cylindrical organelles composed of actin and myosin; responsible for muscle contraction.

Sarcomere

Functional contractile unit of a myofibril extending from one Z-disc to another.

A Band

Dark region of sarcomere where thick and thin filaments overlap.

I Band

Light region containing only thin filaments.

H Zone

Central region of the A band containing only thick filaments.

M Line

Center of the sarcomere where thick filaments are anchored.

Z Disc

Boundary structure that anchors thin filaments and defines sarcomere length.

T-Tubule

Invagination of the sarcolemma that conducts electrical impulses into the muscle fiber.

Sarcoplasmic Reticulum (SR)

Specialized endoplasmic reticulum that stores and releases calcium ions during contraction.

Triad

Structure formed by a T-tubule flanked by two terminal cisternae of the SR.