In
cell-cell contact , signals pass through a cell junction from one cell to adjacent cells.
Membrane-bound signals bind to receptors on adjacent cells in the process of
paracrine signalling.
An example of
autocrine signalling is when cells release signals that affect themselves and nearby target cells.
In
synaptic signalling cells release signals that affect nearby target cells. Cells release signals that travel long distances to affect target cells during
endocrine signalling.