Skeletal Muscle Physiology

These flashcards cover key concepts related to the sarcoplasmic reticulum, muscle contraction, and components of skeletal muscle.

Sarcoplasmic Reticulum

The endoplasmic reticulum of muscle cells; surrounds each myofibril.

Terminal Cisternae

Thicker regions of the sarcoplasmic reticulum at the junction between the A band and I band.

T tubules

Transverse tubules that are part of the sarcoplasmic reticulum and conduct nerve impulses deep inside muscle cells.

Triad

The structure formed by a T tubule and the two terminal cisternae of the sarcoplasmic reticulum.

Sliding Filament Theory

Theory that describes the contraction of skeletal muscle as an increase in the overlap of actin and myosin filaments.

Myofibril

A basic rod-like unit of a muscle cell that is surrounded by the sarcoplasmic reticulum.

Sarcolemma

The cell membrane of a muscle fiber that forms a tube extending deep into the cell.

Actin/Myosin overlap

Increases during contraction and is minimal when the muscle is stretched.

H zone

The central part of the A band in a relaxed muscle where there is no overlap between thick and thin filaments.

Lumen

The cavity of the T tubules that is continuous with the extracellular space.