Final answer:
Intercalated discs in cardiac muscle contain gap junctions and desmosomes, which are crucial for the synchronized contraction and structural integrity of heart muscle cells during contractions.
Step-by-step explanation:
In cardiac muscle, intercalated discs are specialized structures that facilitate the synchronization of heart muscle contractions. They are integral to the function of the sarcolemma, the cell membrane of cardiac muscle cells. These intercalated discs contain gap junctions and desmosomes, both of which perform critical roles in cardiac function.
Gap junctions form channels that allow cations to pass between cardiac muscle cells, enabling the rapid transmission of action potentials necessary for coordinated contractions across the heart muscle, forming a functional unit known as a syncytium. Meanwhile, desmosomes function as structural supports that anchor muscle fibers together, preventing the cells from separating when contracting. Together, the presence of gap junctions and desmosomes in intercalated discs ensure efficient and synchronized contractions of the heart muscle required for effective pumping of blood.