Answer:
Intercalated discs
Step-by-step explanation:
Intercalated discs are thickening of the plasma membrane of cardiac muscle cells and are formed when these cells are attached end to end. Intercalated discs have desmosomes and gap junctions. Desmosomes serves to hold the cardiac muscle fiber together during contraction of cardiac muscles and impart strength. Function of gap junctions is to serve as path for immediate conduction of electric signal to ensure synchronized contraction of cardiac muscle cells.