Final answer:
Transversely located adherens junctions in cardiac muscle, known as intercalated discs, are critical for the mechanical integrity and synchronized contractions of the heart. Intercalated discs consist of desmosomes and gap junctions, allowing the heart to contract as a coordinated unit.
Step-by-step explanation:
Transversely located adherens junctions in cardiac muscle refer to the specialized connections called intercalated discs, which are found at the junctions of adjacent cardiac muscle cells. Intercalated discs are crucial for maintaining the structural integrity of the heart muscle during the stress of contraction and facilitating synchronized contractions. They are part of the sarcolemma and consist of two main types of junctions:
- Desmosomes, which are responsible for mechanically anchoring cardiac muscle fibers together to prevent them from pulling apart during contraction.
- Gap junctions, which form channels allowing the passage of ions and the quick transmission of action potentials between cardiac cells. This results in a phenomenon known as electric coupling, essential for the coordinated contraction of the heart.
The synchronization and efficiency of heart muscle contractions are due to the formation of a functional syncytium - a network of electrically connected cardiac muscle cells.