sarcolemmal membrane
The plasma membrane surrounding individual muscle fibers, critical for excitation-contraction coupling.
Full Definition
The sarcolemmal membrane is the specialized plasma membrane that encloses each skeletal muscle fiber, playing a crucial role in muscle excitation and contraction. This membrane contains voltage-gated sodium channels responsible for action potential propagation and specialized invaginations called T-tubules that facilitate rapid transmission of electrical signals deep into the muscle fiber. The sarcolemma also houses the dystrophin-glycoprotein complex, which provides structural stability and connects the internal cytoskeleton to the extracellular matrix. Disruption of sarcolemmal integrity or its associated protein complexes is implicated in various muscular dystrophies and other neuromuscular disorders.
Usage
Usage note: From Greek 'sarx' (flesh) and 'lemma' (husk); can be shortened to 'sarcolemma'.
In Context
- "Dystrophin deficiency leads to sarcolemmal membrane instability and muscle fiber degeneration." — Pathophysiology textbook
- "The sarcolemmal membrane showed increased permeability on membrane studies." — Research paper