Neighboring cardiac muscle cells in the walls of heart chambers have specialized cell-to-cell contacts that electrically and mechanically link the cells together, permitting the immediate passage of muscle impulses. these cell-to-cell contacts are called

Intercalated discs

Explanation:

The intercalated discs are unique structural formations which are found in the  cells of the heart.

They are equipped for special functions. Thay play a vital role in the bonding of the heart cells and muscles that helps in transmitting the signals between cells.

These cells are known as intercalated cells which helps in cell to cell interaction.

the function of the protein macromolecule is to move things in and out of the cell and transport other molecules in the body. there are many functions of proteins. they are the basic building blocks of living things and are responsible for the growth and repair of body cells and tissues.

explanation:

enzyme speed up the reactions