AP BIOLOGY

Detailed explanation-1: -Cardiac muscle fibres cells also are extensively branched and are connected to one another at their ends by intercalated discs. An intercalated disc allows the cardiac muscle cells to contract in a wave-like pattern so that the heart can work as a pump.

Detailed explanation-2: -An example of juxtacrine signaling is the interaction between the notch receptor, and its ligand, ‘delta’. Cell-cell junctions that contain cadherin complexes also work in a similar manner.

Detailed explanation-3: -Intercalated discs are small connections that join cardiac muscle cells (cardiomyocytes) to each other.

Detailed explanation-4: -The electrical event, the wave of depolarization, is the trigger for muscular contraction. The wave of depolarization begins in the right atrium, and the impulse spreads across the superior portions of both atria and then down through the contractile cells.