Which structure do muscle fibers use to communicate electrical impulses?

Muscle fibers communicate electrical impulses primarily through the sarcolemma, which is the plasma membrane of the muscle cell. When a muscle fiber is stimulated, an action potential, or electrical impulse, travels along the sarcolemma. This process is essential for initiating muscle contraction.

The sarcolemma has specialized properties that allow it to propagate these electrical signals. When the neuromuscular junction is activated, neurotransmitters are released, leading to depolarization of the sarcolemma. This depolarization then spreads along the sarcolemma and down into the transverse tubules (T-tubules) of the muscle cell, allowing the impulse to reach the interior of the fiber and trigger muscle contraction.

Other options such as myofilaments, axon terminals, and the neuromuscular junction play different roles in muscle function. Myofilaments are the contractile proteins (actin and myosin) responsible for muscle contraction but do not communicate electrical signals. Axon terminals are part of the neuron that releases neurotransmitters but are not involved in the propagation of electrical impulses within the muscle fiber itself. The neuromuscular junction is a crucial site for communication between the nerve and muscle, but the actual transmission of the electrical impulse occurs across