Intercalated disc
Pronunciation: in-TER-kah-lay-ted disk
Specialized junctional complexes between cardiac myocytes that facilitate electrical and mechanical coupling for coordinated contraction.
Full Definition
Intercalated discs are unique structural features of cardiac muscle consisting of complex junctional areas between adjacent myocytes that enable the heart to function as a syncytium. These disc-shaped structures contain three types of cell junctions: fascia adherens (anchoring sites for actin filaments), desmosomes (providing mechanical strength), and gap junctions (allowing electrical coupling through connexin proteins). On histologic examination, intercalated discs appear as dark-staining, stepwise lines that run perpendicular to the myofiber direction. Pathological changes to intercalated discs, including disruption of gap junctions or desmosomal proteins, can lead to arrhythmias and cardiomyopathies. These structures are essential for maintaining the mechanical integrity and electrical synchronization of the myocardium.
Usage
Usage note: Use 'disc' rather than 'disk' in medical contexts. May be abbreviated as 'ID' after first use.
In Context
- "The intercalated discs showed normal morphology with intact gap junctions on electron microscopy." — Ultrastructural cardiac analysis
- "Disruption of intercalated disc integrity was noted in areas of acute myocardial injury." — Cardiac pathology report