Intercalated disc

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Area composita
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Intercalated disc
cardiomyocytes in magnified section
Intercalated discs, desmosomes and gap junctions in cardiac muscle fiber.
Details
Part ofCardiac muscle
Identifiers
Latindiscus intercalaris, discus intercalatus
THH2.00.05.2.02006
Anatomical terms of microanatomy]

Intercalated discs or lines of Eberth are microscopic identifying features of

cardiomyocytes) connected by intercalated discs to work as a single functional syncytium. By contrast, skeletal muscle consists of multinucleated muscle fibers and exhibits no intercalated discs. Intercalated discs support synchronized contraction of cardiac tissue in a wave-like pattern so that the heart can work like a pump.[1] They occur at the Z line of the sarcomere
and can be visualized easily when observing a longitudinal section of the tissue.

Structure

Intercalated discs are complex structures that connect adjacent

cardiac muscle cells. The three types of cell junction recognised as making up an intercalated disc are desmosomes, fascia adherens junctions, and gap junctions.[2]

All of these junctions work together as a single unit called the area composita.[2]

Clinical significance

Mutations in the intercalated disc gene are responsible for various

cardiomyopathies that can lead to heart failure.[2]

Ruptured intercalated discs, in this case regarded as a visual artifact.

Ruptured intercalated discs, when seen on histopathology, have two main causes:

Additional signs indicating forceful myocardial contraction are:[5][6]

  • Alternating bundles of hypercontracted myocytes with hyperdistended ones.
  • Square-shaped myocardiocyte nuclei.
  • Hyperdistended myocardiocytes with detached sarcomeres, and in proximity of hypercontracted myocardiocytes.
  • Square-shaped nuclei, indicating forceful myocardial contraction.
    Square-shaped nuclei, indicating forceful myocardial contraction.

References

External links

  • Histology image: 22502loa – Histology Learning System at Boston University — "Ultrastructure of the Cell: cardiac muscle, intercalated disk "