sarcolemma
Noun: * The plasma membrane of a muscle fiber: The sarcolemma is the specialized cell membrane that surrounds and encloses the cytoplasm (sarcoplasm) and the contractile elements (myofibrils) of an individual muscle cell (muscle fiber). It is an excitable membrane that plays a crucial role in conducting the electrical impulses that trigger muscle contraction.
The term "sarcolemma" is a highly specialized biological term used almost exclusively in the fields of anatomy, physiology, cell biology, and medicine. It refers specifically to the structure of muscle cells.
- The sarcolemma is essential for the transmission of action potentials along the muscle fiber.
- Damage to the sarcolemma can lead to muscle cell dysfunction or death.
- In the image, the sarcolemma is clearly visible as the outer boundary of the muscle fiber.
- Sarcolemmal (adjective): Pertaining to or of the nature of the sarcolemma.
- Example: The researcher studied the sarcolemmal proteins involved in ion transport.
- Sarcolemma is a compound word from Greek roots: (flesh, muscle) + (husk, sheath).
- Sarcoplasm (noun): The cytoplasm of a muscle fiber, enclosed by the sarcolemma.
- Myofibril (noun): The long, contractile threads within the sarcoplasm, composed of sarcomeres.
- Muscle fiber membrane
- Myolemma (a less common synonym)
The sarcolemma is distinct from other biological membranes due to its specific function and location. It is not simply a cell membrane but the specialized membrane of a muscle cell, with invaginations called transverse (T) tubules that help rapidly transmit signals to the interior of the cell.
- an extensible membrane enclosing the contractile substance of a muscle fiber