Sarkoplasmatisches

Sarkoplasmatisches is an adjective used in physiology and anatomy to refer to relationships with the sarcoplasm, the cytoplasm of muscle fibers, particularly of skeletal and cardiac muscle. In most contexts it appears in phrases such as sarkoplasmatisches Retikulum, which designates the sarcoplasmic reticulum, a specialized form of smooth endoplasmic reticulum within muscle cells.

The sarcoplasmic reticulum (SR) is a network of membranous tubules and sacs that envelops each myofibril. It functions as the main intracellular storage site for calcium ions (Ca2+), which are essential for muscle contraction. The SR releases Ca2+ into the cytosol in response to an action potential, and the resulting Ca2+ binds to proteins that regulate the interaction between actin and myosin, enabling contraction. After contraction, Ca2+ is pumped back into the SR by Ca2+-ATPases, allowing relaxation.

In skeletal muscle, the SR forms membrane structures called terminal cisternae that couple with transverse tubules (T-tubules) to create a triad at the region between the A and I bands. This arrangement facilitates rapid and coordinated Ca2+ release. In cardiac muscle, the relation typically forms a dyad, with the T-tubule closely associated to a single SR cisterna, supporting excitation-contraction coupling in the heart.

Disorders of calcium handling within the sarkoplasmatisches system can affect muscle function. Abnormal SR calcium release or reuptake is implicated in certain myopathies and cardiac arrhythmias, reflecting the critical role of the sarcoplasmic component in muscle physiology. See also sarcoplasm, sarcoplasmic reticulum, and excitation-contraction coupling.