Gap junctions form pores that connect adjacent cells. In this way signaling molecules, ions and other substances can pass through the pore to the adjacent cell. This type of cell junctions are important in cardiac muscle responses, in brain signaling, during childbirth, etc.
Tight junctions hold the cells together as a rivet would in hardware so it can't be taken apart. This makes it so skin and intestines are very strong and don't break very often
