The structural feature of cells that allows molecules to flow directly from the inside of one cell to the next is called a gap junction.

Here's a breakdown:

* Gap junctions are specialized channels that directly connect the cytoplasm of two adjacent cells.

* These channels are formed by connexons, which are protein complexes that span the plasma membranes of both cells.

* Gap junctions allow for the passage of small molecules, ions, and even some signaling molecules between cells.

* They are particularly important for communication and coordination between cells in tissues like heart muscle, smooth muscle, and epithelial tissues.

Other important features:

* Plasmodesmata are similar structures found in plant cells, connecting the cytoplasm of adjacent cells through the cell wall.

* Tight junctions are also important for cell-to-cell communication, but they prevent the free passage of molecules between cells. They act as a barrier to prevent leakage of fluids and solutes between cells.

Let me know if you'd like more details about any of these structures!