Biological Systems MCAT Practice Exam 2026 – Complete Study Resource

Intercalated disks play a crucial role in connecting cardiac muscle cells, or cardiomyocytes, to one another. These specialized structures contain gap junctions and desmosomes, which facilitate both mechanical and electrical coupling between the cells. The presence of gap junctions allows for the rapid transmission of electrical impulses across a network of cardiac cells, enabling synchronized contractions necessary for effective heart function. This electrical connectivity ensures that when one cell depolarizes, the signal spreads efficiently throughout the cardiac muscle, resulting in a coordinated heartbeat.

The desmosomes within intercalated disks provide structural integrity by holding adjacent cells tightly together during the stress of contraction, preventing them from pulling apart. This combination of electrical and mechanical connection is unique to cardiac muscle and is essential for maintaining the heart's rhythmic pumping action.