Why are gap junctions especially important in cardiac muscle?

1. A gap junction is a protein-lined pore between two adjacent animal cells. 2. It allows ions, nutrients and other small substances to pass directly from cell to cell. 3. In cardiac muscle the electrical signal for contraction is passed efficiently through these junctions. 4. That direct passage allows the heart muscle cells to contract in tandem. 5. Preventing leakage is the job of tight junctions instead, so that answer names the wrong junction. 6. Calcium storage for contraction belongs to the sarcoplasmic reticulum inside each cell. 7. Gap junctions matter because they pass the contraction signal on. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 4 "Cell Structure", section 4.6 Connections between Cells and Cellular Activities_