Which component of an intercalated disc provides in attachment site for actin filaments in cardiac muscle (LQ)
1. A gap junction is a junction between certain cell-types that allows different molecules and ions to pass freely between cells (metabolic coupling).
2. The junction connects the cytoplasm of cells. One Gap junction is composed of two connexons (or hemi channels) which connect across the intercellular space.
3. Gap junctions are particularly important in the cardiac muscle: the signal to contract is passed efficiently through the gap junctions, allowing the heart muscle cells to contract in tandem.
4. However, gap junctions are now known to be expressed in virtually all tissues of the body, with the exception of motile cell types such as sperm or erythrocytes.