In a skeletal muscle fiber, the sarcolemma forms tubules that penetrate into the cell and contact the sarcoplasmic reticulum.
Question
In a skeletal muscle fiber, the sarcolemma forms tubules that penetrate into the cell and contact the sarcoplasmic reticulum.
Solution
Yes, in a skeletal muscle fiber, the sarcolemma, which is the cell membrane, does form tubules known as transverse or T-tubules. These T-tubules penetrate into the cell and are in close contact with the sarcoplasmic reticulum, which is a specialized type of smooth endoplasmic reticulum that stores, releases, and retrieves calcium ions. The T-tubules and the sarcoplasmic reticulum work together to transmit signals from the outside of the muscle cell to the proteins inside the cell that control muscle contraction. When an electrical signal, or action potential, travels along the sarcolemma, it moves down into the T-tubules and stimulates the sarcoplasmic reticulum to release calcium ions into the sarcoplasm, the cytoplasm of the muscle fiber. This increase in calcium ion concentration triggers the muscle fiber to contract.
Similar Questions
What is a muscle fiber structure formed from the sarcolemma that penetrates into the cells?Multiple choice question.SarcolemmaMyofibrilsSacroplasmic reticulumT (transverse) tubules
Deep inward extensions of the sarcolemma form a tunnel-like network inside the muscle cell known as ___________.Group of answer choicestransverse tubulessarcoplasmic reticulummyofilamentsmyofibrils
What causes the striated appearance of skeletal muscle fibers?Multiple ChoiceLocation of the cisternaeOrganization of components of the sarcomeresArrangement of transverse tubulesPosition of the sarcoplasmic reticulum network
What is the sarcolemma?Multiple choice question.A skeletal muscle cellThe plasma membrane of a skeletal muscle cellSpecialized ER of a skeletal muscle cellThe cytoplasm of a skeletal muscle cell
What produces the striations of a skeletal muscle cell? the sarcoplasmic reticulum the arrangement of myofilaments a difference in the thickness of the sarcolemma Thick filaments the T tubules
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