What is sarcolemma and Plasmalemma?
What is sarcolemma and Plasmalemma?
The sarcolemma is a specialized cell membrane which surrounds striated muscle fiber cells. Sometimes called the myolemma, the sarcolemma is similar to a typical plasma membrane but has specialized functions for the muscle cell.
Is sarcolemma same as Plasmalemma?
sarcolemma – plasmalemma of muscle cells. External to this cell membrane is a well developed basement membrane. perimysium – collagenous connective tissue that separates smaller bundles of muscle cells called fascicles.
How is excitation of the sarcolemma?
Excitation refers to the propagation of action potentials along the axon of a motor neuron. Excitation of the sarcolemma is coupled or linked to the contraction of a skeletal muscle fiber. Calcium release from the sarcoplasmic reticulum initiates the contraction.
What causes repolarization of the sarcolemma?
This is called repolarization, during which sodium channels close and potassium channels open. Because positive potassium ions (K+) move from the intracellular space to the extracellular space, this allows the inside of the cell to again become negatively charged relative to the outside.
What does Plasmalemma mean?
cell membrane
Plasmalemma is a less common term for the cell membrane—the thin layer that encloses a cell’s cytoplasm, which is the substance between the membrane and the nucleus. In the context of biology, plasma is used as another word for cytoplasm. The lemma in plasmalemma comes from a Greek word that means “husk.”
What is the Sarcomella?
The sarcolemma is the plasma membrane of the muscle cell and is surrounded by basement membrane and endomysial connective tissue. The sarcolemma is an excitable membrane and shares many properties with the neuronal cell membrane.
What are the steps of excitation?
The EC-coupling cycle involves the following sequence of events: (1) depolarization of the plasma membrane and its membrane invaginations (the t-tubular system) by an action potential; (2) transduction of the depolarization signal to the sarcoplasmic reticulum (SR) membrane; (3) activation of Ca2+ release from the SR …
What is the process of excitation?
Excitation–contraction coupling is the physiological process of converting an electrical stimulus to a mechanical response. It is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction.
What is depolarization of the sarcolemma?
The binding Ach causes depolarization of the sarcolemma by opening ion channels and allowing Na+ ions into the muscle cell. Na+ ions diffuse into the muscle fiber and depolarization occurs. Depolarization creates a wave of action potential (electrical current) across the sarcolemma.
What is the function of a sarcolemma?
The sarcolemma generally maintains the same function in muscle cells as the plasma membrane does in other eukaryote cells. It acts as a barrier between the extracellular and intracellular compartments, defining the individual muscle fiber from its surroundings.
What is plasmalemma in anatomy and physiology?
As the outer layer of your skin separates your body from its environment, the plasma membrane) separates the inner contents of a cell from its exterior environment. This membrane provides a protective barrier around the cell and regulates which materials can pass in or out.
What is the function of the plasmalemma?
the plasmalemma is the first part of the cell affected by changes in the extracellular fluid. It also contains a variety of receptors that allow the cell to recognize and respond to specific molecules in its environment, and to communicate with other cells.
What is a sarcolemma in anatomy?
Sarcolemma Definition The sarcolemma is a specialized cell membrane which surrounds striated muscle fiber cells. Sometimes called the myolemma, the sarcolemma is similar to a typical plasma membrane but has specialized functions for the muscle cell.
What is plasmalemma and how does it work?
Plasmalemma is a less common term for the cell membrane —the thin layer that encloses a cell’s cytoplasm, which is the substance between the membrane and the nucleus. It allows beneficial things to pass through while blocking harmful ones. It is also called the plasma membrane. The cell is the basic structural unit of all living organisms.
What is the medical term for the plasma membrane of muscle?
sar·co·lem·ma. The plasma membrane of a muscle fiber; formerly, the delicate connective tissue of the endomysium was included under this term by some.
What is the plasma membrane composed of?
plasma membrane the membrane that encloses a cell; it is composed of phospholipids, glycolipids, cholesterol, and proteins. The primary structure is a lipid bilayer.
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