Transverse Tubules

The transverse tubules (Figure 8.15) are invaginations of the plasma membrane that connect at periodic intervals with the sarcoplasmic reticulum of muscle. The transverse tubules help to carry the signal from the central nervous system to the entire sarcoplasmic reticulum. This assists the process whereby calcium is evenly released across the myofibrils, stimulating contraction in a coordinated fashion.

See also: Structure of Muscle, The Sliding Filament Model, Sarcoplasmic Reticulum