A gap junction is a specialized connection between two adjacent cells that allows for direct communication. These junctions are formed by proteins called connexins, which create channels that enable the transfer of ions and small molecules. This communication is crucial for various physiological processes, including the coordination of muscle contractions and the regulation of cell growth. Gap junctions are found in many tissues, including the heart, where they help synchronize heartbeats. They play a vital role in maintaining homeostasis by allowing cells to share signals and nutrients, ensuring that tissues function harmoniously.