Biology Forums - Study Force

Discuss the attachments between adjacent cardiac muscle cells. What features are important anatomically and physiologically? Is there a disadvantage to this arrangement?

Cardiac muscle cells are joined by structures called intercalated disks. Abutting cells both have desmosomes, to tightly hold the cells together to withstand the physical force of contraction, and gap junctions, which act as tiny tunnels for ions to cross between cells. In this way, action potentials flow across cardiac muscle cells without disruption, as if the cells were one. One disadvantage of gap junctions is that they can be shut down, promoting fibrillation, which occurs when the cardiac muscle cells contract independently. Rather than producing useful pumping, the heart is only quivering as the teamwork of these millions of cells ceases.