During the propagation of the excitation wave along the sarcolemma, the action potentials travel down the , stimulating the intracellular release of calcium ions.

T-tubules (transverse tubules)

Explanation:

T-tubules, also known as transverse tubules, are narrow tubes that are continuous with the sarcolemma (i.e., the cell membrane of striated muscle cells). In skeletal/cardiac muscle cells, T-tubules form invaginations of the sarcolemma that contain many ion channels involved in excitation-contraction (e-c) coupling of muscle cells. Thus, transverse tubules function to conduct the action potential from the cell membrane (sarcolemma) to the interior of the muscle cell.

sea breeze

explanation:

cool air is going towards land allowing for the land to be cooler, the hotter air gets pushed away from the land.