MUSCLE
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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excess ATP is stored in the tubules
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calcium ions are released into tubules’ extracellular fluid
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action potentials are conducted through the tubules to the inside of the cell
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ATP is produced in the mitochondria found in the tubules
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Detailed explanation-1: -Action potentials are conducted into the interior of muscle fibers via the T-tubules and there they activate voltage-gated channels known as dihydropyridine receptors (DHPR). Unlike in cardiac muscle, very little calcium enters the muscle fiber from the extracellular space (via the DHPR).
Detailed explanation-2: -In cardiac muscle cells, as the action potential passes down the T-tubules it activates L-type calcium channels in the T-tubular membrane. Activation of the L-type calcium channel allows calcium to pass into the cell.
Detailed explanation-3: -Answer and Explanation: Action potential in a muscle cell is initiated by sodium ions in the cell. The cell becomes positive, thus initiating the action potential; this follows muscle contraction where calcium ions are released in the muscle cell, which makes muscles strong.