Final answer:
Intercalated discs contain gap junctions and desmosomes, facilitating synchronized contractions of cardiac muscle by allowing the transmission of electrical impulses and anchoring muscle fibers to withstand contractions.
Step-by-step explanation:
Intercalated discs are essential to the function of cardiac muscle because they consist of gap junctions and desmosomes, which are important structures for cardiac muscle contraction. Gap junctions form channels that allow a depolarizing current to flow between adjacent cardiac muscle cells, enabling electric coupling. It is through these gap junctions that action potentials are quickly transmitted, allowing for the synchronized and coordinated contraction of the heart muscle.
As a result, the heart works as a functional unit called a syncytium. On the other hand, desmosomes anchor cardiac muscle fibers together, ensuring that they do not separate during the intense stress of contraction. This binding together by intercalated discs maintains the structural integrity of the heart during its powerful contractions.